[time-nuts] 10 MHz -> 16 MHz clock multiplier

[Tom Van Baak]

What's the simplest way to generate 16 MHz from 10 MHz? This will be for 
clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and 
low parts count is a goal; jitter is not a concern but absolute long-term phase 
coherence is a must.

The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if 
there's something cheaper, less functional, and maybe not SSOP. Any suggestions?

Thanks,
/tvb


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[time-nuts] 10 MHz -> 16 MHz clock multiplier

[Bill Fuqua]

One way is to divide by  10 and then multiply by 16.
Divide by 10 and then follow by 4 tuned frequency doublers.
This should introduce little phase noise.
Another way to do it is to divide by 10, then pass the output thru a
narrow 16 MHz filter and amplify. Sounds difficult but the filter can be one
or two 16 MHz crystals followed by a simple amplifier. Look at the
reference input circuit for a PTS-160.  The output of the divide by 10 needs to
be asymmetrical so it produces even harmonics. If you are using a
divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
 Ideally the pulse width should be a half period of 16 MHz for the maximum 
harmonic content at 16 MHz.
You can take the output of the frequency divider and send it to a NAND 
gate.

One input of the gate is directly connected and the other is delayed. You can
use an RC with a variable capacitor to ground to get it just right.
Just adjust the capacitor to get the maximum output from your
filter amplifier.
73
Bill wa4lav



At 07:41 PM 1/2/2013 +, you wrote:
What's the simplest way to generate 16 MHz from 10 MHz? This will be for 
clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price 
and low parts count is a goal; jitter is not a concern but absolute 
long-term phase coherence is a must.


The ICS525 (as in TAPR Clock-Block) is a good candidate but I was 
wondering if there's something cheaper, less functional, and maybe not 
SSOP. Any suggestions?


Thanks,
/tvb



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[time-nuts] 10 MHz -> 16 MHz clock multiplier

[Bill Fuqua]

At 12:58 AM 1/4/2013 +, time-nuts-requ...@febo.com wrote:

Where can one get some of these mythical  74HC90 's and 74AC90 's that
have been mentioned.
  None of the usual places have them, ie ebay, digi-key, farnell, or
even the Chinese.
  Also data-sheets are not to be found.
Thanks


This is what happens when one stays up too late
74HC390.

However, any discussion on the technical merits?


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[time-nuts] 10 MHz -> 16 MHz clock multiplier

[Bill Fuqua]

   If you divide by 5 the phase noise sideband amplitude (voltage) will be 
divided by 5.
That is a reduction of 14db for all phase noise sideband frequencies . Then 
when you multiply that by 8 you will add the phase noise
sidebands will be multiplied by 8 or 3x6db or 18 db. So the end result will 
be a
factor (if I did my math right in my head, which is getting more difficult 
these days) 4db increase.
  The crystal filter will reduce the phase noise sidebands to some degree. 
That is to say
if you had a perfect filter you could pass only the carrier with out the 
sidebands and thus
no phase noise. However, if your filter has 1kHz bandwidth you would only 
eliminate the
sidebands beyond 500 Hz on either side of the carrier. So the answer is 
sort of yes.
  When I read the email about multiply by 16 and divide  by 10 it occurred 
to me that
it would be easier to divide and then multiply and then I began to brain 
storm, which

is hard to do when you stay up too late.
  If you chose to use a crystal ladder you need to use 16 MHz parallel 
resonant

crystals since the series resonance will be slightly less than 16 MHz. These
crystals are rather cheap. If you want to use a simple high Q (narrow 
bandwidth)

phasing type filter you need to use a crystal with a 16MHz series resonance and
use a termination resistance greater than the crystals series resistance. 
You can
adjust the crystal filters bandwidth by changing the termination 
resistance. This type of
filter was mostly  used in early vacuum tube receivers. They usually shot 
for a minimum
bandwidth of 500 Hz or so. you need to adjust the "phasing capacitor" so it 
equals the

crystals parallel capacitance to minimize feed thru.
  Experimenting with these filters is a lot of fun. I have made lots of 
crystal filters.

I even have a digital crystal impedance meter so I can compare crystals. If
reducing phase sidebands in not a goal all you need is a filter that will 
eliminate

all the other 2 MHz harmonics.

73
Bill wa4lav


At 05:37 PM 1/4/2013 +, time-nuts-requ...@febo.com wrote:

THis is exactly what they are talking about the 74HC390 can do over
50MHz and costs abut 30 cents.  You don't need ECL or anything so
exotic the 30 cent part will work.   Set it for divide by 5.  I guess
this is imperfect enough that there is some fourth harmonic content in
the 2MHz square wave, then you select that with a narrow band filter
and amplify it to whatever you need.   A smart design might try and
add fourth harmonics be using a slightly not-symetric 2MHz square wave

My question is about the phase noise of the final 16MHz signal.  Do
crystal filters "clean up" the signal.  It seems that after several
16MHz crystals in series the output should look a lot like an XO.



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[time-nuts] 10 MHz -> 16 MHz clock multiplier

[Bill Fuqua]

At 07:51 PM 1/4/2013 +, you wrote:

My question is about the phase noise of the final 16MHz signal.  Do
> crystal filters "clean up" the signal.  It seems that after several
> 16MHz crystals in series the output should look a lot like an XO.
>

For offsets out to 100 Hz or so, using a crystal filter will cause
the signal to have the same flicker noise that an oscillator built
with that crystal would have.  Thus don't try to use some junky
clock crystals to make a crystal filter as described in numerous
ham radio articles about receiver IF filters.  If you have a
residual phase noise measurement system like the Agilent E5505A
and a very low flicker noise source, you can actually measure your
filter crystals.  Of course, the crystal time base in the source
has to be better than the crystals you are measuring.  You also
have to avoid overdriving the crystal.  This will require a low
noise buffer amplifier to bring the signal back up to a high
level.

Now after considering all that, crystal clean up filters don't
sound like such a great idea unless you have no alternative.

Rick Karlquist N6RK

   Flicker noise (1/f ) noise would be introduced by an amplifier and not
by the filter.  I am only suggesting ways to multiply the frequency.
You could use LC filters or a crystal filter. Using 3 doublers would
do the job just as well. Naturally if you are concerned about flicker noise
you could simply make the 2 MHz signal higher in amplitude before selecting
the 8th harmonic.
  I was not saying your going to clean up a good crystal oscillator with a
crystal filter. I though you were talking about generating 16MHz from 10MHz
in a clean way. Using a microcontroller or even most synthesizers 
techniques would make

it even worse.
  The PTS synthesizers have fairly good phase noise when they use 
frequency multiplication,
division, mixing, comb generation and filtering on the most part to achieve 
low phase noise.
The later models use a DDS at the lower frequency levels but do have 
greater phase noise
close to the carrier.  In fact in the SGA unit the reference input goes 
thru a transistor ( to distort it)
and then into a series 10MHz crystal filter so that it can accept either a 
5 or 10 MHz input.
   The crystal also helps filter out any birdies that may be on the 
reference signal.
The filter should be fairly high Q since it has 47 Ohm drive impedance and 
100 Ohm load impedance.

73
Bill wa4lav



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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[paul swed]

Tom.
OK the challenge simple. CD4046 16 MHz vco and div by 8 using a 2 Mhz ref.
Thats pretty easy as they say.
As an alternative and very easy 10 MHz div 2 2MHz X 4 X 2. This requires
BPF but pretty easy also.
Lastly an injection osc. 10 Mhz div to 2 Mhz differentiate and feed to a 16
Mhz osc.
Thats actually the easiest of the approaches.
Regards
Paul


On Wed, Jan 2, 2013 at 1:54 PM, Tom Van Baak  wrote:

> What's the simplest way to generate 16 MHz from 10 MHz? This will be for
> clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price
> and low parts count is a goal; jitter is not a concern but absolute
> long-term phase coherence is a must.
>
> The ICS525 (as in TAPR Clock-Block) is a good candidate but I was
> wondering if there's something cheaper, less functional, and maybe not
> SSOP. Any suggestions?
>
> Thanks,
> /tvb
>
>
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Bruce Griffiths]

Since injection locking is possible when the ratio of the 2 frequencies 
involved is a rational number, a 16 MHz oscillator can be directly 
injection locked to a 10MHz signal without the need for dividers etc.


Bruce

paul swed wrote:

Tom.
OK the challenge simple. CD4046 16 MHz vco and div by 8 using a 2 Mhz ref.
Thats pretty easy as they say.
As an alternative and very easy 10 MHz div 2 2MHz X 4 X 2. This requires
BPF but pretty easy also.
Lastly an injection osc. 10 Mhz div to 2 Mhz differentiate and feed to a 16
Mhz osc.
Thats actually the easiest of the approaches.
Regards
Paul


On Wed, Jan 2, 2013 at 1:54 PM, Tom Van Baak  wrote:

   

What's the simplest way to generate 16 MHz from 10 MHz? This will be for
clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price
and low parts count is a goal; jitter is not a concern but absolute
long-term phase coherence is a must.

The ICS525 (as in TAPR Clock-Block) is a good candidate but I was
wondering if there's something cheaper, less functional, and maybe not
SSOP. Any suggestions?

Thanks,
/tvb


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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[paul swed]

Bruce is right about that fact. Thanks.
Square up the 10 Mhz. Diff the leading edge (It actually doesn't matter)
maybe 2-5pf cap and 300 ohm R to ground. Feed this into a transistor that
is in the bottom end of a one transistor oscillator. There are actually
several ways to inject. Think of a totem pole of 2 transistors.
Use google and do a search and you will see what I am  talking about. There
were some articles that the spread spectrum hams used that describe it.

On Wed, Jan 2, 2013 at 2:48 PM, Bruce Griffiths
wrote:

> Since injection locking is possible when the ratio of the 2 frequencies
> involved is a rational number, a 16 MHz oscillator can be directly
> injection locked to a 10MHz signal without the need for dividers etc.
>
> Bruce
>
>
> paul swed wrote:
>
>> Tom.
>> OK the challenge simple. CD4046 16 MHz vco and div by 8 using a 2 Mhz ref.
>> Thats pretty easy as they say.
>> As an alternative and very easy 10 MHz div 2 2MHz X 4 X 2. This requires
>> BPF but pretty easy also.
>> Lastly an injection osc. 10 Mhz div to 2 Mhz differentiate and feed to a
>> 16
>> Mhz osc.
>> Thats actually the easiest of the approaches.
>> Regards
>> Paul
>>
>>
>> On Wed, Jan 2, 2013 at 1:54 PM, Tom Van Baak  wrote:
>>
>>
>>
>>> What's the simplest way to generate 16 MHz from 10 MHz? This will be for
>>> clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low
>>> price
>>> and low parts count is a goal; jitter is not a concern but absolute
>>> long-term phase coherence is a must.
>>>
>>> The ICS525 (as in TAPR Clock-Block) is a good candidate but I was
>>> wondering if there's something cheaper, less functional, and maybe not
>>> SSOP. Any suggestions?
>>>
>>> Thanks,
>>> /tvb
>>>
>>>
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>>>
>>>
>>>
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>>
>
>
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Bob Camp]

Hi

I think I'd second the thought of join with an ARM or something like it that 
will be happy with 10 MHz in. Next choice would be a PIC24 / dsPIC33 that's 
also happy with 10 MHz in.  The money you will pay for the clock conversion 
chip(s) will go a long way spent on a CPU.

Bob

On Jan 2, 2013, at 1:54 PM, Tom Van Baak  wrote:

> What's the simplest way to generate 16 MHz from 10 MHz? This will be for 
> clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price 
> and low parts count is a goal; jitter is not a concern but absolute long-term 
> phase coherence is a must.
> 
> The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering 
> if there's something cheaper, less functional, and maybe not SSOP. Any 
> suggestions?
> 
> Thanks,
> /tvb
> 
> 
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[kevin-usenet]

> What's the simplest way to generate 16 MHz from 10 MHz?

Well, it's a few dollars and *is* a TSSOP, but I've been playing with
TI's CDCE913/925/937/949 series.  They're nice little I2C-programmable
fractional-N PLL chips.

You can either program them in software, or save the config to on-board
flash and pin-select various configs.

They also have onboard varactors and EFC inputs for making a VCXO.

The on-board VCXO range is 80 to 230 MHz, so I'd multiply the 10 MHz
up to 160 MHz and then divide by 10.

I like to throw one in a circuit and know that I can generate whatever
clocks I need in software.  They're also pin-compatible, so if you lay
down a pad for a part larger than needed, you have spare outputs in case
you need them for something.  (The second digit in the P/N is the number
of PLLs; the third is the number of outputs.)

The main limitation is that there's no way to produce a desired phase
relationship between different divisors for e.g. a half-speed clock.


Looking for something cheaper, I can see SiLabs' Si51210 factory-
programmable part, which is cheaper in quantity, but I don't know
the minimum order quantities.


It depends what you mean by "simplest"; the injection-locking idea is
definitely the simplest circuit, but it does require some up-front work
to find coupling capacitor values that work reliably over tolerance.

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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Gerhard Hoffmann]

Am 02.01.2013 19:54, schrieb Tom Van Baak:

What's the simplest way to generate 16 MHz from 10 MHz? This will be for 
clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and 
low parts count is a goal; jitter is not a concern but absolute long-term phase 
coherence is a must.



Probably not the simplest way, but straightforward & maybe you can 
recycle parts of it:



http://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1.pdf

http://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1_layout.png


That's how I did (optional) 10 MHz  ---> 32 MHz for my DG8SAQ VNWA.
parts are cheap & available  @ digikey.


regards, Gerhard

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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[paul swed]

I looked at the TI chip that really seems simple.

On Wed, Jan 2, 2013 at 3:58 PM, Gerhard Hoffmann  wrote:

> Am 02.01.2013 19:54, schrieb Tom Van Baak:
>
>> What's the simplest way to generate 16 MHz from 10 MHz? This will be for
>> clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price
>> and low parts count is a goal; jitter is not a concern but absolute
>> long-term phase coherence is a must.
>>
>>
> Probably not the simplest way, but straightforward & maybe you can recycle
> parts of it:
>
>
> http://www.hoffmann-**hochfrequenz.de/downloads/**vnwa_sync_1.1.pdf
>
> http://www.hoffmann-**hochfrequenz.de/downloads/**vnwa_sync_1.1_layout.png
>
>
> That's how I did (optional) 10 MHz  ---> 32 MHz for my DG8SAQ VNWA.
> parts are cheap & available  @ digikey.
>
>
> regards, Gerhard
>
>
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[kevin-usenet]

I wrote:
> The on-board VCXO range is 80 to 230 MHz, so I'd multiply the 10 MHz
> up to 160 MHz and then divide by 10.

In case it's not obvious, I meant to write "the on-chip VCO".
Obviously it's *not* a crystal oscillator; I just failed to
supervise my typing fingers carefully enough.

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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Bruce Griffiths]

The optimum width of the injection pulse is equal to 1/2 the period of 
the output frequency of the injection locked oscillator.

In this case a pulse width of around 31.25ns

Bruce

paul swed wrote:

Bruce is right about that fact. Thanks.
Square up the 10 Mhz. Diff the leading edge (It actually doesn't matter)
maybe 2-5pf cap and 300 ohm R to ground. Feed this into a transistor that
is in the bottom end of a one transistor oscillator. There are actually
several ways to inject. Think of a totem pole of 2 transistors.
Use google and do a search and you will see what I am  talking about. There
were some articles that the spread spectrum hams used that describe it.

On Wed, Jan 2, 2013 at 2:48 PM, Bruce Griffiths
wrote:

   

Since injection locking is possible when the ratio of the 2 frequencies
involved is a rational number, a 16 MHz oscillator can be directly
injection locked to a 10MHz signal without the need for dividers etc.

Bruce


paul swed wrote:

 

Tom.
OK the challenge simple. CD4046 16 MHz vco and div by 8 using a 2 Mhz ref.
Thats pretty easy as they say.
As an alternative and very easy 10 MHz div 2 2MHz X 4 X 2. This requires
BPF but pretty easy also.
Lastly an injection osc. 10 Mhz div to 2 Mhz differentiate and feed to a
16
Mhz osc.
Thats actually the easiest of the approaches.
Regards
Paul


On Wed, Jan 2, 2013 at 1:54 PM, Tom Van Baak   wrote:



   

What's the simplest way to generate 16 MHz from 10 MHz? This will be for
clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low
price
and low parts count is a goal; jitter is not a concern but absolute
long-term phase coherence is a must.

The ICS525 (as in TAPR Clock-Block) is a good candidate but I was
wondering if there's something cheaper, less functional, and maybe not
SSOP. Any suggestions?

Thanks,
/tvb


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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Didier Juges]

Tom,

This may not be the answer you are looking for, but the simplest way may be
to use a uC that has a PLL for clock generation.

Didier


On Wed, Jan 2, 2013 at 12:54 PM, Tom Van Baak  wrote:

> What's the simplest way to generate 16 MHz from 10 MHz? This will be for
> clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price
> and low parts count is a goal; jitter is not a concern but absolute
> long-term phase coherence is a must.
>
> The ICS525 (as in TAPR Clock-Block) is a good candidate but I was
> wondering if there's something cheaper, less functional, and maybe not
> SSOP. Any suggestions?
>
> Thanks,
> /tvb
>
>
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[johncroos]

 Interesting problem


Re: 10 MHz -> 16 MHz clock multiplier

 What is low cost?? Serious question.
john k6iql

 

 

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From: time-nuts-request 
To: time-nuts 
Sent: Wed, Jan 2, 2013 9:19 pm
Subject: time-nuts Digest, Vol 102, Issue 10


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Today's Topics:

   1. Re: 10 MHz -> 16 MHz clock multiplier (Didier Juges)
   2. Re: An embedded NTP server (Tom Harris)
   3. Re: An embedded NTP server (Jim Lux)
   4. Re: An embedded NTP server (Michael Tharp)
   5. Re: clock-block any need ? (Magnus Danielson)


--

Message: 1
Date: Wed, 2 Jan 2013 19:31:52 -0600
From: Didier Juges 
To: Tom Van Baak , Discussion of precise time and
frequency measurement 
Subject: Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier
Message-ID:

Content-Type: text/plain; charset=ISO-8859-1

Tom,

This may not be the answer you are looking for, but the simplest way may be
to use a uC that has a PLL for clock generation.

Didier


On Wed, Jan 2, 2013 at 12:54 PM, Tom Van Baak  wrote:

> What's the simplest way to generate 16 MHz from 10 MHz? This will be for
> clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price
> and low parts count is a goal; jitter is not a concern but absolute
> long-term phase coherence is a must.
>
> The ICS525 (as in TAPR Clock-Block) is a good candidate but I was
> wondering if there's something cheaper, less functional, and maybe not
> SSOP. Any suggestions?
>
> Thanks,
> /tvb
>
>
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to
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>


--

Message: 2
Date: Thu, 3 Jan 2013 12:34:15 +1100
From: Tom Harris 
To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] An embedded NTP server
Message-ID:

Content-Type: text/plain; charset=ISO-8859-1

+1 for Forth!

+1 for your opinions on PICs & AVRs. We can buy low end NXP ARM Cortex M0
chips (e.g. LPC1113) for less than the PIC18 we were using before, and it
has a real compiler and (unlike the real world) evidence of intelligent
design!

Do you really need an OS? Surely for a box that is only ever going to be an
NTP server you just need a network interface and good maths? I've just seen
a later comment where you mention floating point support, but would 64 bit
integer maths work just as well?

On 3 January 2013 06:25, Chris Albertson  wrote:

> On Wed, Jan 2, 2013 at 11:16 AM, Poul-Henning Kamp 
> wrote:
>
> > I've given up on PIC and Atmel microcontrollers and their antiquated
> > CPU designs.
> >
> > My life is too short to fight odd-ball compilers, when I can get a
> > real 32 bit CPU and a good compiler instead.
>
> That is a valid point if you are building a one-off project.  Your
> time is worth something.  But if you plan to sell a million AA cell
> battery chargers using a 32-bit controller is uneconomical.   These
> will always be a bigger market for 8-bit chips then for 32-bit chips.
>
> For an NTP server I'd go with something that can run an OS and the NTP
> reverence implementation.  ARM (and others) can do that.
>
> --
>
> Chris Albertson
> Redondo Beach, California
>
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-- 

Tom Harris 


--

Message: 3
Date: Wed, 02 Jan 2013 18:26:24 -0800
From: Jim Lux 
To: time-nuts@febo.com
Subject: Re: [time-nuts] An embedded NTP server
Message-ID: <50e4ec50.1030...@earthlink.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

On 1/2/13 5:34 PM, Tom Harris wrote:
> +1 for Forth!
>
> +1 for your opinions on PICs & AVRs. We can buy low end NXP ARM Cortex M0
> chips (e.g. LPC1113) for less than the PIC18 we were using before, and it
> has a real compiler and (unlike the real world) evidence of intelligent
> design!
>
> Do you really need an OS? Surely for a box that is only ever going to be an
> NTP server you just need 

Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Said Jackson]

How about simply using a 16MHz GPSDO?

We have shipped FireFly-1A units with 16MHz Ocxo..

Those can also generate 16MHz out of a 1PPS reference.

Bye,
Said

Sent From iPhone

On Jan 2, 2013, at 12:58, Gerhard Hoffmann  wrote:

> Am 02.01.2013 19:54, schrieb Tom Van Baak:
>> What's the simplest way to generate 16 MHz from 10 MHz? This will be for 
>> clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price 
>> and low parts count is a goal; jitter is not a concern but absolute 
>> long-term phase coherence is a must.
>> 
> 
> Probably not the simplest way, but straightforward & maybe you can recycle 
> parts of it:
> 
> 
> http://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1.pdf
> 
> http://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1_layout.png
> 
> 
> That's how I did (optional) 10 MHz  ---> 32 MHz for my DG8SAQ VNWA.
> parts are cheap & available  @ digikey.
> 
> 
> regards, Gerhard
> 
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[WarrenS]

Tom

For simple, cheap, low performance and fast to build with junk box parts, 
hard to beat:

What I made long ago for myself (before time-nut days).
I still use it today for low end stuff, and it is all done with standard 
74HC DIP parts.

The main IC is a 74HCT4046 Phase lock loop with internal Osc.
The internal osc output is divided by 16  using a 74HC93. The 10MHz ref is 
divide by 10 using a 74HC90
The two 1 MHz signals are feed into it's phase comparator. A couple of 
resistors and caps and I have a low tech 16 / 8 / 4 / 2 / 1  MHz tracking 
ref.
With a couple of tweaks, I got the noise jitter down to a couple of ns as 
measured with a scope.
16 MHz is pushing the limits of the internal Osc, but I did not have any 
trouble getting there using less than the recommended osc cap.


ws



"What's the simplest way to generate 16 MHz from 10 MHz? This will be for 
clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO).
Low price and low parts count is a goal; jitter is not a concern but 
absolute long-term phase coherence is a must.


The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering 
if there's something cheaper, less functional, and maybe not SSOP. Any 
suggestions?


Thanks,
/tvb 



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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Magnus Danielson]

On 02/01/13 19:54, Tom Van Baak wrote:

What's the simplest way to generate 16 MHz from 10 MHz? This will be for 
clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and 
low parts count is a goal; jitter is not a concern but absolute long-term phase 
coherence is a must.

The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if 
there's something cheaper, less functional, and maybe not SSOP. Any suggestions?


One approach is to divide by 5 to get 2 MHz, but recalling that the 20% 
PWM factor (top bit of divide by 5 counter) has a strong 8th overtone 
compared to the 40% PWM factor, an LC-tank at 16 MHz and a simple 
gain-stage (such as the Wenzel sine input) should be able to pull it 
off. The divide by 5 is standard TTL/CMOS of your choosing.


Cheers,
Magnus

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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Ulrich Bangert]

Tom,

my 50 cents are: Use a 1 Euro expensive ICS503 in a SOIC package to generate
a 160 MHz signal from the 10 MHz without further components needed (except
one c on the VCC and one on the input) and then divide by 10. Expect a 50 ps
one sigma jitter on the output. You MUST use capacitive coupling with an
external oscillator. Easily breadboarded! Have used such a configuration to
generate phase locked clock signals for older FPGAs without internal clock
generation.

Best regards
Ulrich 

> -Ursprungliche Nachricht-
> Von: time-nuts-boun...@febo.com 
> [mailto:time-nuts-boun...@febo.com] Im Auftrag von Tom Van Baak
> Gesendet: Mittwoch, 2. Januar 2013 19:55
> An: Discussion of precise time and frequency measurement
> Betreff: [time-nuts] 10 MHz -> 16 MHz clock multiplier
> 
> 
> What's the simplest way to generate 16 MHz from 10 MHz? This 
> will be for clocking a microcontroller at 16 MHz given 10 MHz 
> (Cs/Rb/GPSDO). Low price and low parts count is a goal; 
> jitter is not a concern but absolute long-term phase 
> coherence is a must.
> 
> The ICS525 (as in TAPR Clock-Block) is a good candidate but I 
> was wondering if there's something cheaper, less functional, 
> and maybe not SSOP. Any suggestions?
> 
> Thanks,
> /tvb
> 
> 
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Hal Murray]

> What is low cost?? Serious question.

The OP (tvb) said "maybe not SSOP" so he's not interested in typical high 
volume production techniques.  I assume he's interested home brew stuff using 
low cost parts and free labor.

I'd put the knee of the curve at $10.  $1 would be great.  $100 is too much.

You can get different answers if you pick $3 or $30 rather than my $10, but I 
think that's the right ballpark.




-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[M. Simon]

I would not use the 4046 these days. It has a dead band around zero phase 
error. 


I would use the 9046 which has no dead band. In addition the integrator supply 
is a cleaner design. It is a current source. 


The data sheet explains it.

http://www.nxp.com/documents/data_sheet/74HCT9046A.pdf

In addition the internal VCO is rated at 17 MHz (typ - 5.5V supply). Depending 
on how much jitter you can handle a low cost VCXO will give better performance 
than the on chip osc. Hz/Volt of the VCO is important in keeping jitter down. 
Smaller is better. 

Use the type 2 phase detector. (PC2) If you don't mind the extra chips run the 
phase detector at between 100KHz and 400KHz. It is a matter of the speed of the 
technology. 1 MHz is pushing it. It might also be a good idea to bias the 
internal VCO with a trimpot and let the phase detector just supply the 
correction. Well it is starting to get complicated. 


Simon


Message: 2
Date: Wed, 2 Jan 2013 21:19:16 -0800
From: "WarrenS" 
To: "Discussion of precise time and frequency measurement"
    
Subject: Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier
Message-ID: <87417D31224740BFB6BBB320B762E80D@Warcon28Gz>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
    reply-type=original

Tom

For simple, cheap, low performance and fast to build with junk box parts, 
hard to beat:
What I made long ago for myself (before time-nut days).
I still use it today for low end stuff, and it is all done with standard 
74HC DIP parts.
The main IC is a 74HCT4046 Phase lock loop with internal Osc.
The internal osc output is divided by 16  using a 74HC93. The 10MHz ref is 
divide by 10 using a 74HC90
The two 1 MHz signals are feed into it's phase comparator. A couple of 
resistors and caps and I have a low tech 16 / 8 / 4 / 2 / 1  MHz tracking 
ref.
With a couple of tweaks, I got the noise jitter down to a couple of ns as 
measured with a scope.
16 MHz is pushing the limits of the internal Osc, but I did not have any 
trouble getting there using less than the recommended osc cap.

ws



"What's the simplest way to generate 16 MHz from 10 MHz? This will be for 
clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO).
Low price and low parts count is a goal; jitter is not a concern but 
absolute long-term phase coherence is a must.

The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering 
if there's something cheaper, less functional, and maybe not SSOP. Any 
suggestions?

Thanks,
/tvb 


 



Engineering is the art of making what you want from what you can get at a 
profit.
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[EWKehren]

Ulrich
you beat me to it, we have been using lately the ICS 512 and 570 for some  
of our projects. If symmetry is not required 80 MHz and a 74 AC 90 will do, 
if  symmetry is a must  the only low cost way I know is 160  MHz and a $ 2  
MAX3000A gate array. We actually did a symmetrical divide by 3 and 5.
Bert Kehren
 
 
 
In a message dated 1/3/2013 4:11:45 A.M. Eastern Standard Time,  
df...@ulrich-bangert.de writes:

Tom,

my 50 cents are: Use a 1 Euro expensive ICS503 in a  SOIC package to 
generate
a 160 MHz signal from the 10 MHz without further  components needed (except
one c on the VCC and one on the input) and then  divide by 10. Expect a 50 
ps
one sigma jitter on the output. You MUST use  capacitive coupling with an
external oscillator. Easily breadboarded! Have  used such a configuration to
generate phase locked clock signals for older  FPGAs without internal clock
generation.

Best regards
Ulrich  

> -Ursprungliche Nachricht-
> Von:  time-nuts-boun...@febo.com 
> [mailto:time-nuts-boun...@febo.com] Im  Auftrag von Tom Van Baak
> Gesendet: Mittwoch, 2. Januar 2013  19:55
> An: Discussion of precise time and frequency measurement
>  Betreff: [time-nuts] 10 MHz -> 16 MHz clock multiplier
> 
>  
> What's the simplest way to generate 16 MHz from 10 MHz? This 
>  will be for clocking a microcontroller at 16 MHz given 10 MHz 
>  (Cs/Rb/GPSDO). Low price and low parts count is a goal; 
> jitter is not  a concern but absolute long-term phase 
> coherence is a must.
>  
> The ICS525 (as in TAPR Clock-Block) is a good candidate but I  
> was wondering if there's something cheaper, less functional, 
>  and maybe not SSOP. Any suggestions?
> 
> Thanks,
>  /tvb
> 
> 
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Max]

Where can one get some of these mythical  74HC90 's and 74AC90 's that 
have been mentioned.
 None of the usual places have them, ie ebay, digi-key, farnell, or 
even the Chinese.

 Also data-sheets are not to be found.
Thanks



On 4/01/2013 5:13 AM, Bill Fuqua wrote:

One way is to divide by  10 and then multiply by 16.
Divide by 10 and then follow by 4 tuned frequency doublers.
This should introduce little phase noise.
Another way to do it is to divide by 10, then pass the output thru a
narrow 16 MHz filter and amplify. Sounds difficult but the filter can 
be one

or two 16 MHz crystals followed by a simple amplifier. Look at the
reference input circuit for a PTS-160.  The output of the divide by 10 
needs to

be asymmetrical so it produces even harmonics. If you are using a
divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
 Ideally the pulse width should be a half period of 16 MHz for the 
maximum harmonic content at 16 MHz.
You can take the output of the frequency divider and send it to a 
NAND gate.
One input of the gate is directly connected and the other is delayed. 
You can

use an RC with a variable capacitor to ground to get it just right.
Just adjust the capacitor to get the maximum output from your
filter amplifier.
73
Bill wa4lav



At 07:41 PM 1/2/2013 +, you wrote:
What's the simplest way to generate 16 MHz from 10 MHz? This will be 
for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). 
Low price and low parts count is a goal; jitter is not a concern but 
absolute long-term phase coherence is a must.


The ICS525 (as in TAPR Clock-Block) is a good candidate but I was 
wondering if there's something cheaper, less functional, and maybe 
not SSOP. Any suggestions?


Thanks,
/tvb



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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Gerhard Hoffmann]

Am 04.01.2013 01:59, schrieb Max:
Where can one get some of these mythical  74HC90 's and 74AC90 's that 
have been mentioned.
 None of the usual places have them, ie ebay, digi-key, farnell, or 
even the Chinese.

 Also data-sheets are not to be found.

you can't find 'em because they're not there(Lou Reed,  "Busload Of 
Faith")


regards, Gerhard



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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[David]

They do not exist as I found out (again) not long ago.  The last 7490
made was LS (low power schottky) and I use quite a few of them.
Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they
apparently either never went into production or very few were
produced.

The closest non-TTL alternative that I found was the 74HC390 or
74HCT390 which is basically two 7490 counters in one package.

On Fri, 04 Jan 2013 11:59:01 +1100, Max  wrote:

>Where can one get some of these mythical  74HC90 's and 74AC90 's that 
>have been mentioned.
>  None of the usual places have them, ie ebay, digi-key, farnell, or 
>even the Chinese.
>  Also data-sheets are not to be found.
>Thanks
>
>
>
>On 4/01/2013 5:13 AM, Bill Fuqua wrote:
>> One way is to divide by  10 and then multiply by 16.
>> Divide by 10 and then follow by 4 tuned frequency doublers.
>> This should introduce little phase noise.
>> Another way to do it is to divide by 10, then pass the output thru a
>> narrow 16 MHz filter and amplify. Sounds difficult but the filter can 
>> be one
>> or two 16 MHz crystals followed by a simple amplifier. Look at the
>> reference input circuit for a PTS-160.  The output of the divide by 10 
>> needs to
>> be asymmetrical so it produces even harmonics. If you are using a
>> divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
>>  Ideally the pulse width should be a half period of 16 MHz for the 
>> maximum harmonic content at 16 MHz.
>> You can take the output of the frequency divider and send it to a 
>> NAND gate.
>> One input of the gate is directly connected and the other is delayed. 
>> You can
>> use an RC with a variable capacitor to ground to get it just right.
>> Just adjust the capacitor to get the maximum output from your
>> filter amplifier.
>> 73
>> Bill wa4lav
>>
>>
>>
>> At 07:41 PM 1/2/2013 +, you wrote:
>>> What's the simplest way to generate 16 MHz from 10 MHz? This will be 
>>> for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). 
>>> Low price and low parts count is a goal; jitter is not a concern but 
>>> absolute long-term phase coherence is a must.
>>>
>>> The ICS525 (as in TAPR Clock-Block) is a good candidate but I was 
>>> wondering if there's something cheaper, less functional, and maybe 
>>> not SSOP. Any suggestions?
>>>
>>> Thanks,
>>> /tvb
>>
>>
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>> and follow the instructions there.
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Tom Miller]

Isn't there a fast divide by N counter that you could set to 10? Maybe even 
in ECL?



- Original Message - 
From: "David" 
To: "Discussion of precise time and frequency measurement" 


Sent: Thursday, January 03, 2013 8:49 PM
Subject: Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier


They do not exist as I found out (again) not long ago.  The last 7490
made was LS (low power schottky) and I use quite a few of them.
Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they
apparently either never went into production or very few were
produced.

The closest non-TTL alternative that I found was the 74HC390 or
74HCT390 which is basically two 7490 counters in one package.

On Fri, 04 Jan 2013 11:59:01 +1100, Max  wrote:


Where can one get some of these mythical  74HC90 's and 74AC90 's that
have been mentioned.
 None of the usual places have them, ie ebay, digi-key, farnell, or
even the Chinese.
 Also data-sheets are not to be found.
Thanks



On 4/01/2013 5:13 AM, Bill Fuqua wrote:

One way is to divide by  10 and then multiply by 16.
Divide by 10 and then follow by 4 tuned frequency doublers.
This should introduce little phase noise.
Another way to do it is to divide by 10, then pass the output thru a
narrow 16 MHz filter and amplify. Sounds difficult but the filter can
be one
or two 16 MHz crystals followed by a simple amplifier. Look at the
reference input circuit for a PTS-160.  The output of the divide by 10
needs to
be asymmetrical so it produces even harmonics. If you are using a
divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
 Ideally the pulse width should be a half period of 16 MHz for the
maximum harmonic content at 16 MHz.
You can take the output of the frequency divider and send it to a
NAND gate.
One input of the gate is directly connected and the other is delayed.
You can
use an RC with a variable capacitor to ground to get it just right.
Just adjust the capacitor to get the maximum output from your
filter amplifier.
73
Bill wa4lav



At 07:41 PM 1/2/2013 +, you wrote:

What's the simplest way to generate 16 MHz from 10 MHz? This will be
for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO).
Low price and low parts count is a goal; jitter is not a concern but
absolute long-term phase coherence is a must.

The ICS525 (as in TAPR Clock-Block) is a good candidate but I was
wondering if there's something cheaper, less functional, and maybe
not SSOP. Any suggestions?

Thanks,
/tvb



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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Max]

Ahhh,  the beauty of the 74xx90 is that you can have a symetrical output 
by using the divide by two after the divide by five.


Max


On 4/01/2013 1:02 PM, Tom Miller wrote:
Isn't there a fast divide by N counter that you could set to 10? Maybe 
even in ECL?



- Original Message - From: "David" 
To: "Discussion of precise time and frequency measurement" 


Sent: Thursday, January 03, 2013 8:49 PM
Subject: Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier


They do not exist as I found out (again) not long ago.  The last 7490
made was LS (low power schottky) and I use quite a few of them.
Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they
apparently either never went into production or very few were
produced.

The closest non-TTL alternative that I found was the 74HC390 or
74HCT390 which is basically two 7490 counters in one package.

On Fri, 04 Jan 2013 11:59:01 +1100, Max  wrote:


Where can one get some of these mythical 74HC90 's and 74AC90 's that
have been mentioned.
 None of the usual places have them, ie ebay, digi-key, farnell, or
even the Chinese.
 Also data-sheets are not to be found.
Thanks



On 4/01/2013 5:13 AM, Bill Fuqua wrote:

One way is to divide by  10 and then multiply by 16.
Divide by 10 and then follow by 4 tuned frequency doublers.
This should introduce little phase noise.
Another way to do it is to divide by 10, then pass the output 
thru a

narrow 16 MHz filter and amplify. Sounds difficult but the filter can
be one
or two 16 MHz crystals followed by a simple amplifier. Look at the
reference input circuit for a PTS-160.  The output of the divide by 10
needs to
be asymmetrical so it produces even harmonics. If you are using a
divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
 Ideally the pulse width should be a half period of 16 MHz for the
maximum harmonic content at 16 MHz.
You can take the output of the frequency divider and send it to a
NAND gate.
One input of the gate is directly connected and the other is delayed.
You can
use an RC with a variable capacitor to ground to get it just right.
Just adjust the capacitor to get the maximum output from your
filter amplifier.
73
Bill wa4lav



At 07:41 PM 1/2/2013 +, you wrote:

What's the simplest way to generate 16 MHz from 10 MHz? This will be
for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO).
Low price and low parts count is a goal; jitter is not a concern but
absolute long-term phase coherence is a must.

The ICS525 (as in TAPR Clock-Block) is a good candidate but I was
wondering if there's something cheaper, less functional, and maybe
not SSOP. Any suggestions?

Thanks,
/tvb



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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[David]

Oh, there are lots, well, at least some presetable synchronous
counters in fast logic families that could be used but that would
require extra glue logic.  Alternatively if you just want to divide by
5 or some other small fixed number, you can use a couple of flip-flips
and gates.

On Thu, 03 Jan 2013 21:02:32 -0500, "Tom Miller"
 wrote:

>Isn't there a fast divide by N counter that you could set to 10? Maybe even 
>in ECL?
>
>
>- Original Message - 
>From: "David" 
>To: "Discussion of precise time and frequency measurement" 
>
>Sent: Thursday, January 03, 2013 8:49 PM
>Subject: Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier
>
>
>They do not exist as I found out (again) not long ago.  The last 7490
>made was LS (low power schottky) and I use quite a few of them.
>Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they
>apparently either never went into production or very few were
>produced.
>
>The closest non-TTL alternative that I found was the 74HC390 or
>74HCT390 which is basically two 7490 counters in one package.
>
>On Fri, 04 Jan 2013 11:59:01 +1100, Max  wrote:
>
>>Where can one get some of these mythical  74HC90 's and 74AC90 's that
>>have been mentioned.
>>  None of the usual places have them, ie ebay, digi-key, farnell, or
>>even the Chinese.
>>  Also data-sheets are not to be found.
>>Thanks
>>
>>
>>
>>On 4/01/2013 5:13 AM, Bill Fuqua wrote:
>>> One way is to divide by  10 and then multiply by 16.
>>> Divide by 10 and then follow by 4 tuned frequency doublers.
>>> This should introduce little phase noise.
>>> Another way to do it is to divide by 10, then pass the output thru a
>>> narrow 16 MHz filter and amplify. Sounds difficult but the filter can
>>> be one
>>> or two 16 MHz crystals followed by a simple amplifier. Look at the
>>> reference input circuit for a PTS-160.  The output of the divide by 10
>>> needs to
>>> be asymmetrical so it produces even harmonics. If you are using a
>>> divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
>>>  Ideally the pulse width should be a half period of 16 MHz for the
>>> maximum harmonic content at 16 MHz.
>>> You can take the output of the frequency divider and send it to a
>>> NAND gate.
>>> One input of the gate is directly connected and the other is delayed.
>>> You can
>>> use an RC with a variable capacitor to ground to get it just right.
>>> Just adjust the capacitor to get the maximum output from your
>>> filter amplifier.
>>> 73
>>> Bill wa4lav
>>>
>>>
>>>
>>> At 07:41 PM 1/2/2013 +, you wrote:
>>>> What's the simplest way to generate 16 MHz from 10 MHz? This will be
>>>> for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO).
>>>> Low price and low parts count is a goal; jitter is not a concern but
>>>> absolute long-term phase coherence is a must.
>>>>
>>>> The ICS525 (as in TAPR Clock-Block) is a good candidate but I was
>>>> wondering if there's something cheaper, less functional, and maybe
>>>> not SSOP. Any suggestions?
>>>>
>>>> Thanks,
>>>> /tvb

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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Rex]

On 1/3/2013 6:22 PM, David wrote:

Alternatively if you just want to divide by
5 or some other small fixed number, you can use a couple of flip-flips
and gates.

Flip-flips are good for digitally implementing tick-tick clocks, right? 
:-) (Use flop-flops for tock-tock.)



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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Hal Murray]

tmil...@skylinenet.net said:
> Isn't there a fast divide by N counter that you could set to 10? Maybe even
> in ECL? 

The 74xx16y are 4 bit loadable counters.  2 are binary, 2 are decimal.
I think 1 of each pair has a synchronous reset/clear, the other is async.

Mouser has the 74AC161 and 74AC163 in stock.  They are binary.
I think you need an inverter to hook up the ripple carry out to load them to 
6 to make a divide by 10.



-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Chris Albertson]

THis is exactly what they are talking about the 74HC390 can do over
50MHz and costs abut 30 cents.  You don't need ECL or anything so
exotic the 30 cent part will work.   Set it for divide by 5.  I guess
this is imperfect enough that there is some fourth harmonic content in
the 2MHz square wave, then you select that with a narrow band filter
and amplify it to whatever you need.   A smart design might try and
add fourth harmonics be using a slightly not-symetric 2MHz square wave

My question is about the phase noise of the final 16MHz signal.  Do
crystal filters "clean up" the signal.  It seems that after several
16MHz crystals in series the output should look a lot like an XO.

On Thu, Jan 3, 2013 at 6:02 PM, Tom Miller  wrote:
> Isn't there a fast divide by N counter that you could set to 10? Maybe even
> in ECL?
>
>
> - Original Message - From: "David" 
> To: "Discussion of precise time and frequency measurement"
> 
> Sent: Thursday, January 03, 2013 8:49 PM
> Subject: Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier
>
>
>
> They do not exist as I found out (again) not long ago.  The last 7490
> made was LS (low power schottky) and I use quite a few of them.
> Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they
> apparently either never went into production or very few were
> produced.
>
> The closest non-TTL alternative that I found was the 74HC390 or
> 74HCT390 which is basically two 7490 counters in one package.
>
> On Fri, 04 Jan 2013 11:59:01 +1100, Max  wrote:
>
>> Where can one get some of these mythical  74HC90 's and 74AC90 's that
>> have been mentioned.
>>  None of the usual places have them, ie ebay, digi-key, farnell, or
>> even the Chinese.
>>  Also data-sheets are not to be found.
>> Thanks
>>
>>
>>
>> On 4/01/2013 5:13 AM, Bill Fuqua wrote:
>>>
>>> One way is to divide by  10 and then multiply by 16.
>>> Divide by 10 and then follow by 4 tuned frequency doublers.
>>> This should introduce little phase noise.
>>> Another way to do it is to divide by 10, then pass the output thru a
>>> narrow 16 MHz filter and amplify. Sounds difficult but the filter can
>>> be one
>>> or two 16 MHz crystals followed by a simple amplifier. Look at the
>>> reference input circuit for a PTS-160.  The output of the divide by 10
>>> needs to
>>> be asymmetrical so it produces even harmonics. If you are using a
>>> divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
>>>  Ideally the pulse width should be a half period of 16 MHz for the
>>> maximum harmonic content at 16 MHz.
>>> You can take the output of the frequency divider and send it to a
>>> NAND gate.
>>> One input of the gate is directly connected and the other is delayed.
>>> You can
>>> use an RC with a variable capacitor to ground to get it just right.
>>> Just adjust the capacitor to get the maximum output from your
>>> filter amplifier.
>>> 73
>>> Bill wa4lav
>>>
>>>
>>>
>>> At 07:41 PM 1/2/2013 +, you wrote:
>>>>
>>>> What's the simplest way to generate 16 MHz from 10 MHz? This will be
>>>> for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO).
>>>> Low price and low parts count is a goal; jitter is not a concern but
>>>> absolute long-term phase coherence is a must.
>>>>
>>>> The ICS525 (as in TAPR Clock-Block) is a good candidate but I was
>>>> wondering if there's something cheaper, less functional, and maybe
>>>> not SSOP. Any suggestions?
>>>>
>>>> Thanks,
>>>> /tvb
>>>
>>>
>>>
>>> ___
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>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>
>>
>>
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>
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-- 

Chris Albertson
Redondo Beach, California

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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Bob Bownes]

Paul Wade built a board recently to do just this. www.w1ghz.org.

Bob


On Fri, Jan 4, 2013 at 12:16 PM, Chris Albertson
wrote:

> THis is exactly what they are talking about the 74HC390 can do over
> 50MHz and costs abut 30 cents.  You don't need ECL or anything so
> exotic the 30 cent part will work.   Set it for divide by 5.  I guess
> this is imperfect enough that there is some fourth harmonic content in
> the 2MHz square wave, then you select that with a narrow band filter
> and amplify it to whatever you need.   A smart design might try and
> add fourth harmonics be using a slightly not-symetric 2MHz square wave
>
> My question is about the phase noise of the final 16MHz signal.  Do
> crystal filters "clean up" the signal.  It seems that after several
> 16MHz crystals in series the output should look a lot like an XO.
>
> On Thu, Jan 3, 2013 at 6:02 PM, Tom Miller  wrote:
> > Isn't there a fast divide by N counter that you could set to 10? Maybe
> even
> > in ECL?
> >
> >
> > - Original Message - From: "David" 
> > To: "Discussion of precise time and frequency measurement"
> > 
> > Sent: Thursday, January 03, 2013 8:49 PM
> > Subject: Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier
> >
> >
> >
> > They do not exist as I found out (again) not long ago.  The last 7490
> > made was LS (low power schottky) and I use quite a few of them.
> > Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they
> > apparently either never went into production or very few were
> > produced.
> >
> > The closest non-TTL alternative that I found was the 74HC390 or
> > 74HCT390 which is basically two 7490 counters in one package.
> >
> > On Fri, 04 Jan 2013 11:59:01 +1100, Max  wrote:
> >
> >> Where can one get some of these mythical  74HC90 's and 74AC90 's that
> >> have been mentioned.
> >>  None of the usual places have them, ie ebay, digi-key, farnell, or
> >> even the Chinese.
> >>  Also data-sheets are not to be found.
> >> Thanks
> >>
> >>
> >>
> >> On 4/01/2013 5:13 AM, Bill Fuqua wrote:
> >>>
> >>> One way is to divide by  10 and then multiply by 16.
> >>> Divide by 10 and then follow by 4 tuned frequency doublers.
> >>> This should introduce little phase noise.
> >>> Another way to do it is to divide by 10, then pass the output thru
> a
> >>> narrow 16 MHz filter and amplify. Sounds difficult but the filter can
> >>> be one
> >>> or two 16 MHz crystals followed by a simple amplifier. Look at the
> >>> reference input circuit for a PTS-160.  The output of the divide by 10
> >>> needs to
> >>> be asymmetrical so it produces even harmonics. If you are using a
> >>> divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
> >>>  Ideally the pulse width should be a half period of 16 MHz for the
> >>> maximum harmonic content at 16 MHz.
> >>> You can take the output of the frequency divider and send it to a
> >>> NAND gate.
> >>> One input of the gate is directly connected and the other is delayed.
> >>> You can
> >>> use an RC with a variable capacitor to ground to get it just right.
> >>> Just adjust the capacitor to get the maximum output from your
> >>> filter amplifier.
> >>> 73
> >>> Bill wa4lav
> >>>
> >>>
> >>>
> >>> At 07:41 PM 1/2/2013 +, you wrote:
> >>>>
> >>>> What's the simplest way to generate 16 MHz from 10 MHz? This will be
> >>>> for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO).
> >>>> Low price and low parts count is a goal; jitter is not a concern but
> >>>> absolute long-term phase coherence is a must.
> >>>>
> >>>> The ICS525 (as in TAPR Clock-Block) is a good candidate but I was
> >>>> wondering if there's something cheaper, less functional, and maybe
> >>>> not SSOP. Any suggestions?
> >>>>
> >>>> Thanks,
> >>>> /tvb
> >>>
> >>>
> >>>
> >>> ___
> >>> time-nuts mailing list -- time-nuts@febo.com
> >>> To unsubscribe, go to
> >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >>> and follow the instructions there.
> >>
> >>
&g

Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Rick Karlquist]

Chris Albertson wrote:

> My question is about the phase noise of the final 16MHz signal.  Do
> crystal filters "clean up" the signal.  It seems that after several
> 16MHz crystals in series the output should look a lot like an XO.
>

For offsets out to 100 Hz or so, using a crystal filter will cause
the signal to have the same flicker noise that an oscillator built
with that crystal would have.  Thus don't try to use some junky
clock crystals to make a crystal filter as described in numerous
ham radio articles about receiver IF filters.  If you have a
residual phase noise measurement system like the Agilent E5505A
and a very low flicker noise source, you can actually measure your
filter crystals.  Of course, the crystal time base in the source
has to be better than the crystals you are measuring.  You also
have to avoid overdriving the crystal.  This will require a low
noise buffer amplifier to bring the signal back up to a high
level.

Now after considering all that, crystal clean up filters don't
sound like such a great idea unless you have no alternative.

Rick Karlquist N6RK


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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Jim Lux]

On 1/4/13 10:25 AM, Rick Karlquist wrote:

Chris Albertson wrote:


My question is about the phase noise of the final 16MHz signal.  Do
crystal filters "clean up" the signal.  It seems that after several
16MHz crystals in series the output should look a lot like an XO.



For offsets out to 100 Hz or so, using a crystal filter will cause
the signal to have the same flicker noise that an oscillator built
with that crystal would have.  Thus don't try to use some junky
clock crystals to make a crystal filter as described in numerous
ham radio articles about receiver IF filters.


An excellent point.. After all, what is a crystal oscillator but 
essentially a noise source followed by a crystal filter.




Now after considering all that, crystal clean up filters don't
sound like such a great idea unless you have no alternative.


I can't think of a good practical example, but say you had a kind of 
noisy source, and a box full of crystals that happened to be at the same 
frequency, and for some odd reason, you didn't just build an oscillator 
with the crystal.  (perhaps some sort of distribution amp system where 
you want all the outputs to be coherent to some reference, and the 
reference is noisy?)







Rick Karlquist N6RK


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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[EWKehren]

How about getting back to basics.
Is it a one off, if production how many and what are the specification  
requirements? Otherwise on this list it can go on for a year.
Bert Kehren
 
 
In a message dated 1/4/2013 6:11:14 P.M. Eastern Standard Time,  
wlfuq...@uky.edu writes:

At 07:51  PM 1/4/2013 +, you wrote:
>My question is about the phase noise of  the final 16MHz signal.  Do
> > crystal filters "clean up" the  signal.  It seems that after several
> > 16MHz crystals in  series the output should look a lot like an XO.
>  >
>
>For offsets out to 100 Hz or so, using a crystal filter  will cause
>the signal to have the same flicker noise that an oscillator  built
>with that crystal would have.  Thus don't try to use some  junky
>clock crystals to make a crystal filter as described in  numerous
>ham radio articles about receiver IF filters.  If you  have a
>residual phase noise measurement system like the Agilent  E5505A
>and a very low flicker noise source, you can actually measure  your
>filter crystals.  Of course, the crystal time base in the  source
>has to be better than the crystals you are measuring.  You  also
>have to avoid overdriving the crystal.  This will require a  low
>noise buffer amplifier to bring the signal back up to a  high
>level.
>
>Now after considering all that, crystal  clean up filters don't
>sound like such a great idea unless you have no  alternative.
>
>Rick Karlquist N6RK
Flicker noise  (1/f ) noise would be introduced by an amplifier and not
by the  filter.  I am only suggesting ways to multiply the frequency.
You  could use LC filters or a crystal filter. Using 3 doublers would
do the job  just as well. Naturally if you are concerned about flicker noise
you could  simply make the 2 MHz signal higher in amplitude before selecting
the 8th  harmonic.
I was not saying your going to clean up a good  crystal oscillator with a
crystal filter. I though you were talking about  generating 16MHz from 10MHz
in a clean way. Using a microcontroller or even  most synthesizers 
techniques would make
it even worse.
The PTS synthesizers have fairly good phase noise when they use 
frequency  multiplication,
division, mixing, comb generation and filtering on the most  part to 
achieve 
low phase noise.
The later models use a DDS at the  lower frequency levels but do have 
greater phase noise
close to the  carrier.  In fact in the SGA unit the reference input goes 
thru a  transistor ( to distort it)
and then into a series 10MHz crystal filter so  that it can accept either a 
5 or 10 MHz input.
The  crystal also helps filter out any birdies that may be on the 
reference  signal.
The filter should be fairly high Q since it has 47 Ohm drive  impedance and 
100 Ohm load impedance.
73
Bill  wa4lav



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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Bob Camp]

Hi

As I recall the spec was:

1) Cheap
2) no phase slips on the 16 MHz relative to 10 MHz
3) Cheap

Bob

On Jan 4, 2013, at 7:18 PM, ewkeh...@aol.com wrote:

> How about getting back to basics.
> Is it a one off, if production how many and what are the specification  
> requirements? Otherwise on this list it can go on for a year.
> Bert Kehren
> 
> 
> In a message dated 1/4/2013 6:11:14 P.M. Eastern Standard Time,  
> wlfuq...@uky.edu writes:
> 
> At 07:51  PM 1/4/2013 +, you wrote:
>> My question is about the phase noise of  the final 16MHz signal.  Do
>>> crystal filters "clean up" the  signal.  It seems that after several
>>> 16MHz crystals in  series the output should look a lot like an XO.
>>> 
>> 
>> For offsets out to 100 Hz or so, using a crystal filter  will cause
>> the signal to have the same flicker noise that an oscillator  built
>> with that crystal would have.  Thus don't try to use some  junky
>> clock crystals to make a crystal filter as described in  numerous
>> ham radio articles about receiver IF filters.  If you  have a
>> residual phase noise measurement system like the Agilent  E5505A
>> and a very low flicker noise source, you can actually measure  your
>> filter crystals.  Of course, the crystal time base in the  source
>> has to be better than the crystals you are measuring.  You  also
>> have to avoid overdriving the crystal.  This will require a  low
>> noise buffer amplifier to bring the signal back up to a  high
>> level.
>> 
>> Now after considering all that, crystal  clean up filters don't
>> sound like such a great idea unless you have no  alternative.
>> 
>> Rick Karlquist N6RK
> Flicker noise  (1/f ) noise would be introduced by an amplifier and not
> by the  filter.  I am only suggesting ways to multiply the frequency.
> You  could use LC filters or a crystal filter. Using 3 doublers would
> do the job  just as well. Naturally if you are concerned about flicker noise
> you could  simply make the 2 MHz signal higher in amplitude before selecting
> the 8th  harmonic.
> I was not saying your going to clean up a good  crystal oscillator with a
> crystal filter. I though you were talking about  generating 16MHz from 10MHz
> in a clean way. Using a microcontroller or even  most synthesizers 
> techniques would make
> it even worse.
> The PTS synthesizers have fairly good phase noise when they use 
> frequency  multiplication,
> division, mixing, comb generation and filtering on the most  part to 
> achieve 
> low phase noise.
> The later models use a DDS at the  lower frequency levels but do have 
> greater phase noise
> close to the  carrier.  In fact in the SGA unit the reference input goes 
> thru a  transistor ( to distort it)
> and then into a series 10MHz crystal filter so  that it can accept either a 
> 5 or 10 MHz input.
> The  crystal also helps filter out any birdies that may be on the 
> reference  signal.
> The filter should be fairly high Q since it has 47 Ohm drive  impedance and 
> 100 Ohm load impedance.
> 73
> Bill  wa4lav
> 
> 
> 
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[paul swed]

I think the thread branched and as I recall started something like this.
Someone needed a "Simple" 16 Mhz for a uproc made from a 10 Mhz source.
Two reasonable answers were given.
Injection locked oscillator
Typical div and mult/filter.
A third and kind of interesting for me a Ti chip soic digital pll.
Then the thread went a whole bunch of directions.
Wonder if who ever needed an answer got the answer?
Regards
Paul
WB8TSL

On Fri, Jan 4, 2013 at 7:18 PM,  wrote:

> How about getting back to basics.
> Is it a one off, if production how many and what are the specification
> requirements? Otherwise on this list it can go on for a year.
> Bert Kehren
>
>
> In a message dated 1/4/2013 6:11:14 P.M. Eastern Standard Time,
> wlfuq...@uky.edu writes:
>
> At 07:51  PM 1/4/2013 +, you wrote:
> >My question is about the phase noise of  the final 16MHz signal.  Do
> > > crystal filters "clean up" the  signal.  It seems that after several
> > > 16MHz crystals in  series the output should look a lot like an XO.
> >  >
> >
> >For offsets out to 100 Hz or so, using a crystal filter  will cause
> >the signal to have the same flicker noise that an oscillator  built
> >with that crystal would have.  Thus don't try to use some  junky
> >clock crystals to make a crystal filter as described in  numerous
> >ham radio articles about receiver IF filters.  If you  have a
> >residual phase noise measurement system like the Agilent  E5505A
> >and a very low flicker noise source, you can actually measure  your
> >filter crystals.  Of course, the crystal time base in the  source
> >has to be better than the crystals you are measuring.  You  also
> >have to avoid overdriving the crystal.  This will require a  low
> >noise buffer amplifier to bring the signal back up to a  high
> >level.
> >
> >Now after considering all that, crystal  clean up filters don't
> >sound like such a great idea unless you have no  alternative.
> >
> >Rick Karlquist N6RK
> Flicker noise  (1/f ) noise would be introduced by an amplifier and not
> by the  filter.  I am only suggesting ways to multiply the frequency.
> You  could use LC filters or a crystal filter. Using 3 doublers would
> do the job  just as well. Naturally if you are concerned about flicker
> noise
> you could  simply make the 2 MHz signal higher in amplitude before
> selecting
> the 8th  harmonic.
> I was not saying your going to clean up a good  crystal oscillator with a
> crystal filter. I though you were talking about  generating 16MHz from
> 10MHz
> in a clean way. Using a microcontroller or even  most synthesizers
> techniques would make
> it even worse.
> The PTS synthesizers have fairly good phase noise when they use
> frequency  multiplication,
> division, mixing, comb generation and filtering on the most  part to
> achieve
> low phase noise.
> The later models use a DDS at the  lower frequency levels but do have
> greater phase noise
> close to the  carrier.  In fact in the SGA unit the reference input goes
> thru a  transistor ( to distort it)
> and then into a series 10MHz crystal filter so  that it can accept either a
> 5 or 10 MHz input.
> The  crystal also helps filter out any birdies that may be on the
> reference  signal.
> The filter should be fairly high Q since it has 47 Ohm drive  impedance and
> 100 Ohm load impedance.
> 73
> Bill  wa4lav
>
>
>
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> To unsubscribe, go to
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>
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Bob Camp]

HI

Ok, it's TimeNuts, we need numbers…

Say no phase slips is 0.1 UI on the 16 MHz. That would be a jitter number of 
6.25 ns RMS.

Bob

On Jan 4, 2013, at 7:18 PM, ewkeh...@aol.com wrote:

> How about getting back to basics.
> Is it a one off, if production how many and what are the specification  
> requirements? Otherwise on this list it can go on for a year.
> Bert Kehren
> 
> 
> In a message dated 1/4/2013 6:11:14 P.M. Eastern Standard Time,  
> wlfuq...@uky.edu writes:
> 
> At 07:51  PM 1/4/2013 +, you wrote:
>> My question is about the phase noise of  the final 16MHz signal.  Do
>>> crystal filters "clean up" the  signal.  It seems that after several
>>> 16MHz crystals in  series the output should look a lot like an XO.
>>> 
>> 
>> For offsets out to 100 Hz or so, using a crystal filter  will cause
>> the signal to have the same flicker noise that an oscillator  built
>> with that crystal would have.  Thus don't try to use some  junky
>> clock crystals to make a crystal filter as described in  numerous
>> ham radio articles about receiver IF filters.  If you  have a
>> residual phase noise measurement system like the Agilent  E5505A
>> and a very low flicker noise source, you can actually measure  your
>> filter crystals.  Of course, the crystal time base in the  source
>> has to be better than the crystals you are measuring.  You  also
>> have to avoid overdriving the crystal.  This will require a  low
>> noise buffer amplifier to bring the signal back up to a  high
>> level.
>> 
>> Now after considering all that, crystal  clean up filters don't
>> sound like such a great idea unless you have no  alternative.
>> 
>> Rick Karlquist N6RK
> Flicker noise  (1/f ) noise would be introduced by an amplifier and not
> by the  filter.  I am only suggesting ways to multiply the frequency.
> You  could use LC filters or a crystal filter. Using 3 doublers would
> do the job  just as well. Naturally if you are concerned about flicker noise
> you could  simply make the 2 MHz signal higher in amplitude before selecting
> the 8th  harmonic.
> I was not saying your going to clean up a good  crystal oscillator with a
> crystal filter. I though you were talking about  generating 16MHz from 10MHz
> in a clean way. Using a microcontroller or even  most synthesizers 
> techniques would make
> it even worse.
> The PTS synthesizers have fairly good phase noise when they use 
> frequency  multiplication,
> division, mixing, comb generation and filtering on the most  part to 
> achieve 
> low phase noise.
> The later models use a DDS at the  lower frequency levels but do have 
> greater phase noise
> close to the  carrier.  In fact in the SGA unit the reference input goes 
> thru a  transistor ( to distort it)
> and then into a series 10MHz crystal filter so  that it can accept either a 
> 5 or 10 MHz input.
> The  crystal also helps filter out any birdies that may be on the 
> reference  signal.
> The filter should be fairly high Q since it has 47 Ohm drive  impedance and 
> 100 Ohm load impedance.
> 73
> Bill  wa4lav
> 
> 
> 
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Rex]

On 1/4/2013 4:48 PM, Bob Camp wrote:

Hi

As I recall the spec was:

1) Cheap
2) no phase slips on the 16 MHz relative to 10 MHz
3) Cheap

Bob



GAK!

Here is the original from TVB

What's the simplest way to generate 16 MHz from 10 MHz? This will be for 
clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and 
low parts count is a goal; jitter is not a concern but absolute long-term phase 
coherence is a must.

The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if 
there's something cheaper, less functional, and maybe not SSOP. Any suggestions?

Thanks,
/tvb

This cluster f**k of responses losing track of the original but blathering on 
for days is so typical of the group lately.






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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Ed Breya]

I'm kind of late to the party on this one, and don't want to reopen and 
send it off on a tangent. I agree with the injection-lock method, but 
just want to suggest that since most uPs and uCs have their own CMOS 
oscillator built in, the simplest solution would be to just use that as 
intended, with a cheap 16 MHz crystal or ceramic resonator, and 
injection lock it to a low impedance version of the 10 MHz clock, via an 
RCD network. It may need a variable cap to tweak the resonator to the 
lock frequency.


Ed

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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[paul swed]

Ed you are late to the dance. But do offer an additional piece of the
puzzle.
RCD I will guess is a RC differentiator. And your suggestion does get rid
of a separate oscillator. It wasn't my post. But would guess you just jam
the diff pulse into the osc amp in that the xtal feeds?
Regards
Paul
WB8TSL

On Mon, Jan 7, 2013 at 5:30 PM, Ed Breya  wrote:

> I'm kind of late to the party on this one, and don't want to reopen and
> send it off on a tangent. I agree with the injection-lock method, but just
> want to suggest that since most uPs and uCs have their own CMOS oscillator
> built in, the simplest solution would be to just use that as intended, with
> a cheap 16 MHz crystal or ceramic resonator, and injection lock it to a low
> impedance version of the 10 MHz clock, via an RCD network. It may need a
> variable cap to tweak the resonator to the lock frequency.
>
> Ed
>
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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Ed Breya]

Actually, I was referring to an RC and Diode network in anticipation of 
the possible need for more signal shaping flexibility, depending on the 
signals and circuitry. The built-in oscillators are usually self-biased 
CMOS inverters intended to go with crystals, and usually a couple of 
small phase shift caps to ground. If you inject the right amount of 
reference frequency at the input, the oscillator should sync up. Since 
it's for a fixed frequency, the required lock range can be quite small - 
it needs to be enough to compensate for drift in the resonator and 
circuits - so the injection level probably can be small. Since the 
oscillator input has plenty of gain, and the reference is likely a very 
low impedance, I think a fairly high impedance passive coupling network 
to link the two should suffice, without any extra active circuitry.


Ed

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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Tom Van Baak]

A week ago I asked about a 10 MHz to 16 MHz multiplier. Thanks very much for 
the suggestions and interesting discussion.

> What's the simplest way to generate 16 MHz from 10 MHz? This
> will be for clocking a microcontroller at 16 MHz given 10 MHz
> (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter
> is not a concern but absolute long-term phase coherence is a must.
> 
> The ICS525 (as in TAPR Clock-Block) is a good candidate but I
> was wondering if there's something cheaper, less functional, and
> maybe not SSOP. Any suggestions?
> 
> Thanks,
> /tvb

A few of you wanted to know more background. Some portable 
microcontroller-based timer/counters use a 16 MHz xtal timebase. To 
transparently give them "atomic" accuracy I thought it would be a cute hack to 
simply feed them 16 MHz as derived from a good 10 MHz (which we all have). For 
a quick test I used a house 10 MHz referenced DS345 to produce the 16 MHz 
square wave. I know some DDS have round-off error but the DS345, at least at 
this frequency, maintained phase to the nanosecond.

Not wanting to tie up my DS345 indefinitely, I wondered for this fixed 10:16 
(5:8) frequency ratio if there was cheap, simple, or clever solution. The TAPR 
Clock-Block came to mind. The ICS525 chip it uses is cheap (under $5) and 
trivial to configure so that was clearly one solution. But I was curious what 
the group would propose.

Anyway, thanks to all who contributed. If there are any stones left unturned, 
send me email off-line.

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Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier

[Joseph Gray]

Don't leave us in suspense :-) What method did you decide to use?

Joe Gray
W5JG

On Mon, Jan 7, 2013 at 8:54 PM, Tom Van Baak  wrote:
> A week ago I asked about a 10 MHz to 16 MHz multiplier. Thanks very much for 
> the suggestions and interesting discussion.
>
>> What's the simplest way to generate 16 MHz from 10 MHz? This
>> will be for clocking a microcontroller at 16 MHz given 10 MHz
>> (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter
>> is not a concern but absolute long-term phase coherence is a must.
>>
>> The ICS525 (as in TAPR Clock-Block) is a good candidate but I
>> was wondering if there's something cheaper, less functional, and
>> maybe not SSOP. Any suggestions?
>>
>> Thanks,
>> /tvb
>
> A few of you wanted to know more background. Some portable 
> microcontroller-based timer/counters use a 16 MHz xtal timebase. To 
> transparently give them "atomic" accuracy I thought it would be a cute hack 
> to simply feed them 16 MHz as derived from a good 10 MHz (which we all have). 
> For a quick test I used a house 10 MHz referenced DS345 to produce the 16 MHz 
> square wave. I know some DDS have round-off error but the DS345, at least at 
> this frequency, maintained phase to the nanosecond.
>
> Not wanting to tie up my DS345 indefinitely, I wondered for this fixed 10:16 
> (5:8) frequency ratio if there was cheap, simple, or clever solution. The 
> TAPR Clock-Block came to mind. The ICS525 chip it uses is cheap (under $5) 
> and trivial to configure so that was clearly one solution. But I was curious 
> what the group would propose.
>
> Anyway, thanks to all who contributed. If there are any stones left unturned, 
> send me email off-line.
>
> /tvb
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