Re: [time-nuts] nuts about position (cheap receiver)

[Gabs Ricalde]

On Sat, May 5, 2018 at 12:08 AM, Mark Sims  wrote:
> You could add doppler to the RINEX file.   All the receivers with raw 
> messages seem to output that.

I think the Doppler measurements can be omitted for static
positioning. CSRS-PPP results for a submission with/without Doppler
are identical.

> I am playing with the Furuno GT87 output.  It does not output carrier phase 
> data (only pseudorange / doppler / SNR).   CSRS-PPP can still process that.

It seems the carrier phase is not used for single frequency
submissions. The summary file says
Observation processed:   CODE

For dual frequency,
Observation processed:   CODE
and there are carrier phase residuals in the PDF report.
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Re: [time-nuts] Ashtech Z12 question.

[Peter Monta]

>
> Does the Z12 have an internal memory backup battery?


Yes, there are two lithium thionyl chloride cells, Tadiran TL-5104.  They
are 3.6 V primary cells, cylinders roughly AA in size, with spot-welded
axial leads.  That part is obsolete, but Digikey has an equivalent,
TL-5903/P, which worked fine for me.  They're easy enough to replace, but
the inside of the box is a little awkward, with multiple board levels,
screws, and hinges.  Clip the spent cells free of their leads to make the
desoldering a little easier and to reduce the risk of heating the cells
(the chemistry is hazardous).  There is also some foam double-sided tape
helping to hold the cells in place; will need to replace that as well.

The two cells are wired in a diode-OR, so a single cell will also work (for
half as long).  While I was waiting for the shipment, I used a single
lithium coin cell, 3.0 V, to tide the box over, which also worked fine.

Cheers,
Peter
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Re: [time-nuts] Ashtech Z12 question.

[Bob kb8tq]

Hi

What you describe sure sounds like a ram battery died sort of thing. I’ve never 
noticed one in the boards I’ve
torn apart. I’d also admit that was a few years back ….

Bob

> On May 6, 2018, at 6:12 PM, Mark Sims  wrote:
> 
> I just added support for the Z12 to Lady Heather and fired up my Z12 for the 
> first time in a few years.   It powers up in some kind of a weird loopback 
> mode and you have to reset the receiver memory to get it working.   
> 
> Does the Z12 have an internal memory backup battery?   Mine is currently 
> doing a long L1/L2 RINEX capture and I can't open it and check right now.
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[time-nuts] Ashtech Z12 question.

[Mark Sims]

I just added support for the Z12 to Lady Heather and fired up my Z12 for the 
first time in a few years.   It powers up in some kind of a weird loopback mode 
and you have to reset the receiver memory to get it working.   

Does the Z12 have an internal memory backup battery?   Mine is currently doing 
a long L1/L2 RINEX capture and I can't open it and check right now.
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[time-nuts] WWVB: measuring local 60 KHz noise

[Alberto di Bene]

On 5/6/2018 6:39 AM, Charles Steinmetz wrote:

So, yes, a sound card designed for signals up to ~22kHz should handle
SAQ at ~17kHz, but sound cards that can digitize signals above 22kHz are
rare.  Some "professional" sound cards handle signal frequencies up to
~40kHz, but very, very few handle signal frequencies higher than that.
There are also digitizers designed more for instrumentation and data
acquisition than audio that may meet your requirements.

Bob and Charles,

  you are of course both quite right.
The card used for SAQ was the Delta 44 which is a semi-professional card.

For higher frequencies I have had quite good results with the E-MU 1212M, which
is a professional, mastering grade, sound card, used also in recording studios.

http://www.creative.com/emu/products/product.aspx?pid=19169

Not exactly inexpensive, but its 120dB signal-to-noise ratio cannot be 
overlooked.

73  Alberto  I2PHD




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Re: [time-nuts] WWVB: measuring local 60 KHz noise

[John Ackermann N8UR]

Long ago I did some WWVB signal-to-noise measurements with an HP 3586C 
selective voltmeter (commonly used by the FMT-nuts).  I measured the signal 
power at 60.0 kHz with 20 Hz bandwidth.  Then I measured the power a small 
offset plus and minus  (100 Hz?  I don't recall), and took the mean of the two 
to get the noise power.  I used a voltage-probe antenna.  

Since all readings were taken with the same bandwidth I didn't bother 
normalizing to 1 Hz, and just used the dBm difference between the signal and 
mean noise as the result.  I took measurements every 5 minutes or so to capture 
the 24 hour cycle of SNR.

John

On May 6, 2018, 1:09 PM, at 1:09 PM, Charles Steinmetz  
wrote:
>Hal wrote:
>
>> I assume the problem is noise.  Is there any simple way to measure
>the noise
>> around 60 KHz?  How about not so simple?
>>
>> Extra credit for a way that others nuts can reproduce so we can
>compare the
>> noise at my location with other locations.
>
>For any location near a city, the noise level (QRM and QRN -- mostly
>the 
>former unless there is storm activity within a few hundred km) is 
>shockingly high.  High enough to be clearly seen and measured with a 
>good spectrum analyzer.  So the *simplest* way (but not necessarily the
>
>cheapest, depending on what is in your lab already) is to use a good 
>spec an with noise integration over the band of interest (e.g., HP
>3585A 
>or B).  You get noise density readings in volts per root Hz.  Divide by
>
>the antenna length and you have volts per root Hz per meter.
>
>Lacking a suitable spec an, any receiver with a reasonably narrow rx
>B/W 
>and a calibrated, input-referred detector can be used.  Wave analyzers 
>(frequency-selectable voltmeters, e.g., HP 3586) are good candidates,
>as 
>are some commercial receivers with calibrated "S" meters (e.g., Ten-Tec
>
>RX340).  It would also be pretty easy to design a simple "sniffer"-type
>
>receiver (input op-amp, active filter, logarithmic detector feeding a 
>standard 1mA meter movement) that could be calibrated by design from 
>first principles and that everyone interested could build for, perhaps,
>
>$25-30.
>
>In the suburbs of a fairly large US city with aerial electric service,
>I 
>generally see noise densities measured in tens to hundreds of uV per 
>root Hz per meter below 100kHz.  In other, similar locations I have
>seen 
>as much as hundreds of mV or more per root Hz per meter.  It depends on
>
>local factors (whether the electric service is buried or aerial, how 
>well the power utility maintains its equipment, how far away the
>nearest 
>industrial neighborhood is, how far between dwellings, how much noisy 
>technology the neighbors use, etc, etc.).
>
>In order to compare with others, everyone needs to use the same
>antenna. 
>  There are lots of possibilities, but for the sake of universality I 
>recommend a 1m vertical whip.  Everyone can make one of those.
>
>Note that this sort of antenna is NOT the best type to minimize
>received 
>noise and maximize received S/N ratio.  For that, you generally want a 
>balanced, shielded loop.
>
>Best regards,
>
>Charles
>
>
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Re: [time-nuts] WWVB: measuring local 60 KHz noise

[Bob kb8tq]

Hi

First off, I don’t think there *is* an ideal antenna that “just works”. Maybe a 
proper set of EMAG 
probes that come with calibration sheets come close. For a home built this or 
that …. there are
a lot of variables. 

First up is very much part of receiving WWVB in the first place. Coax to an 
antenna can have currents
on the outer shield. If they meet up with everything else at the antenna, you 
are not just measuring 
the antenna output. Equally, if reception is the goal, you may have a ton of 
noise that you didn’t really
want to have. Of course, the coax might act as a really good antenna …. who 
knows. 

Something like a 6” diameter single turn  loop with a good choke at the antenna 
end of the coax would
be my first choice. Not super sensitive. It’s not the ideal reception antenna. 
For chasing down noise, smaller
is often better. As mentioned earlier we are after stuff that may be in the 
millivolts per meter range. 

Classic data:

ftp://ftp.ngdc.noaa.gov/ionosonde/documentation/CCIR%20-%20Characteristics%20and%20Applications%20of%20Atmospheric%20Radio%20Noise%20Data.PDF
 


puts the atmospheric noise at 120 db above KTB in the vicinity of 60 KHz. That 
would put it in the roughly
-54 dbm / Hz range. If your spectrum analyzer has a 1KHz bandwidth, that’s 30 
db relative to 1 Hz. Your
SA should read about -24 dbm ( with an efficient antenna).  Coming up with a 
1/4 wave vertical at 60 KHz
may make getting those numbers a bit difficult :). Bottom line is still — 
there’s a lot of noise at 60 KHz. Also
note that the report came out *long* before the modern era of 60 KHz switchers 
…..

Bob 

> On May 6, 2018, at 1:08 PM, Charles Steinmetz  wrote:
> 
> Hal wrote:
> 
>> I assume the problem is noise.  Is there any simple way to measure the noise
>> around 60 KHz?  How about not so simple?
>> 
>> Extra credit for a way that others nuts can reproduce so we can compare the
>> noise at my location with other locations.
> 
> For any location near a city, the noise level (QRM and QRN -- mostly the 
> former unless there is storm activity within a few hundred km) is shockingly 
> high.  High enough to be clearly seen and measured with a good spectrum 
> analyzer.  So the *simplest* way (but not necessarily the cheapest, depending 
> on what is in your lab already) is to use a good spec an with noise 
> integration over the band of interest (e.g., HP 3585A or B).  You get noise 
> density readings in volts per root Hz.  Divide by the antenna length and you 
> have volts per root Hz per meter.
> 
> Lacking a suitable spec an, any receiver with a reasonably narrow rx B/W and 
> a calibrated, input-referred detector can be used.  Wave analyzers 
> (frequency-selectable voltmeters, e.g., HP 3586) are good candidates, as are 
> some commercial receivers with calibrated "S" meters (e.g., Ten-Tec RX340).  
> It would also be pretty easy to design a simple "sniffer"-type receiver 
> (input op-amp, active filter, logarithmic detector feeding a standard 1mA 
> meter movement) that could be calibrated by design from first principles and 
> that everyone interested could build for, perhaps, $25-30.
> 
> In the suburbs of a fairly large US city with aerial electric service, I 
> generally see noise densities measured in tens to hundreds of uV per root Hz 
> per meter below 100kHz.  In other, similar locations I have seen as much as 
> hundreds of mV or more per root Hz per meter.  It depends on local factors 
> (whether the electric service is buried or aerial, how well the power utility 
> maintains its equipment, how far away the nearest industrial neighborhood is, 
> how far between dwellings, how much noisy technology the neighbors use, etc, 
> etc.).
> 
> In order to compare with others, everyone needs to use the same antenna.  
> There are lots of possibilities, but for the sake of universality I recommend 
> a 1m vertical whip.  Everyone can make one of those.
> 
> Note that this sort of antenna is NOT the best type to minimize received 
> noise and maximize received S/N ratio.  For that, you generally want a 
> balanced, shielded loop.
> 
> Best regards,
> 
> Charles
> 
> 
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Re: [time-nuts] WWVB: measuring local 60 KHz noise

[Brooke Clarke]

Hi Hal:

You might want to check the orientation and location of the antenna before 
digging into more technical areas.
It's been my experience there's a lot of AC mains conducted noise at 60 kHz.
http://www.prc68.com/I/LF-Ant.shtml#Noise
http://www.prc68.com/I/Spec_0002.shtml - 0 to 200 kHz spectrum plot (PS when 
LORAN-C was on the air)
Another source of noise is an LCD screen.
Note Wellenbrook Communications suggests placing their loop antenna 100 feet 
from your house.

The loopstick antenna in the UltraLink is a single ferrite rod with nulls off the ends, so orientation is important, not 
so much that you have to point the maximum at WWVB, but that you don't want to point the null at WWVB.  I'm in 
California and have had to relocate WWVB clocks on walls 90 degrees to where I'd rather have them because of this.

http://www.prc68.com/I/Loop.shtml
http://www.prc68.com/I/Shadow-Clock.shtml#WT5360U

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

 Original Message 

Review/background:  I have an UltraLink 333 WWVB receiver.  It didn't work.
Several weeks ago. a discussion here mentioned that the phone cable between
the main box and antenna needs to be straight through rather than the typical
reversed.  That was my problem.  With the correct cable, the meter shows
signal and bounces around such that with practice, I could probably read the
bit pattern.  But it didn't lock up.

That was several weeks ago.  I left it running.  When I looked last night, it
had figured out that it is 2018.  I wasn't watching or monitoring, so I don't
know how long it took.

I assume the problem is noise.  Is there any simple way to measure the noise
around 60 KHz?  How about not so simple?

Extra credit for a way that others nuts can reproduce so we can compare the
noise at my location with other locations.

Can any audio cards be pushed that high?  I see sample rates of 192K, but I
don't know if that is useful.

I'd also like to measure the propagation delays on WWV so a setup for HF that
also works down to 60 KHz would be interesting.

--

The UltraLink documentation says the display has a slot for a C or H.  The C is 
for Colorado and the H is for Hawaii.  Did WWVH have a low frequency 
transmitter many years ago?  The NIST history of WWVH doesn't mention it.

My guess is a cut+paste from a version that listened to WWV/WWVH.





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Re: [time-nuts] 4046 replacement

[Magnus Danielson]

Hi Charles,

On 05/06/2018 06:08 PM, Charles Steinmetz wrote:
> Magnus wrote:
> 
>> If you use it without care and knowledge, beware. That goes for any
>> tool we apply
> 
> Indeed!  The Cardinal Rule of design!  (So often unfollowed)
> 
> "An engineer is someone who can figure out what questions need to be
> asked, figure out how to answer them, and tell when they are correctly
> answered."

Indeed. I don't claim to be expert on the 4046 family of PLL chips, but
at least I can share my experience and let you know about the things I
learned from being bitten.

Then, reading Gardners book, and advancing to full PI loop, I feel more
comfortable about mixer or S/R-gate loops. The "magic" of some detectors
have become less of a benefit for many designs. In general, most of my
designs have become much simpler and robust. However, it's always good
to have alternatives.

Cheers,
Magnus
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Re: [time-nuts] WWVB: measuring local 60 KHz noise

[Charles Steinmetz]

Hal wrote:


I assume the problem is noise.  Is there any simple way to measure the noise
around 60 KHz?  How about not so simple?

Extra credit for a way that others nuts can reproduce so we can compare the
noise at my location with other locations.


For any location near a city, the noise level (QRM and QRN -- mostly the 
former unless there is storm activity within a few hundred km) is 
shockingly high.  High enough to be clearly seen and measured with a 
good spectrum analyzer.  So the *simplest* way (but not necessarily the 
cheapest, depending on what is in your lab already) is to use a good 
spec an with noise integration over the band of interest (e.g., HP 3585A 
or B).  You get noise density readings in volts per root Hz.  Divide by 
the antenna length and you have volts per root Hz per meter.


Lacking a suitable spec an, any receiver with a reasonably narrow rx B/W 
and a calibrated, input-referred detector can be used.  Wave analyzers 
(frequency-selectable voltmeters, e.g., HP 3586) are good candidates, as 
are some commercial receivers with calibrated "S" meters (e.g., Ten-Tec 
RX340).  It would also be pretty easy to design a simple "sniffer"-type 
receiver (input op-amp, active filter, logarithmic detector feeding a 
standard 1mA meter movement) that could be calibrated by design from 
first principles and that everyone interested could build for, perhaps, 
$25-30.


In the suburbs of a fairly large US city with aerial electric service, I 
generally see noise densities measured in tens to hundreds of uV per 
root Hz per meter below 100kHz.  In other, similar locations I have seen 
as much as hundreds of mV or more per root Hz per meter.  It depends on 
local factors (whether the electric service is buried or aerial, how 
well the power utility maintains its equipment, how far away the nearest 
industrial neighborhood is, how far between dwellings, how much noisy 
technology the neighbors use, etc, etc.).


In order to compare with others, everyone needs to use the same antenna. 
 There are lots of possibilities, but for the sake of universality I 
recommend a 1m vertical whip.  Everyone can make one of those.


Note that this sort of antenna is NOT the best type to minimize received 
noise and maximize received S/N ratio.  For that, you generally want a 
balanced, shielded loop.


Best regards,

Charles


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Re: [time-nuts] 4046 replacement

[Charles Steinmetz]

Magnus wrote:


If you use it without care and knowledge, beware. That goes for any tool we 
apply


Indeed!  The Cardinal Rule of design!  (So often unfollowed)

"An engineer is someone who can figure out what questions need to be 
asked, figure out how to answer them, and tell when they are correctly 
answered."


Best regards,

Charles


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Re: [time-nuts] WWVB: measuring local 60 KHz noise

[Alberto di Bene]

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Re: [time-nuts] 4046 replacement

[Magnus Danielson]

Hi,

On 05/06/2018 01:02 PM, Charles Steinmetz wrote:
> Alexander wrote:
> 
>> but as I wrote a while ego ADI has a bit different chip which is free of
>> dead zone and much faster
> 
> Hell, there are literally hundreds of PLL chips, lots of them better at
> various things than the 4046.  I did not suggest that the 4046/7046/9046
> is the best PLL for any particular purpose (and I did say I rarely use
> them).  My points were just (i) that the 4046 doesn't perform as
> terribly as a lot of people seem to think if you know a few easy tricks,
> and (ii) that the 9046 is better on all counts without the need for such
> tricks.
> 
> It seems that lots of people like the 4046 series chips (including the
> 7046 and 9046), partly due to familiarity, partly because there are
> thousands of published circuits that use them and not everybody wants to
> completely redesign circuits that are already known to work, and
> certainly because they are dirt cheap (unlike the fancier Analog Devices
> parts, some of which are quite pricey).  I thought these folks might
> like to know how to optimize performance with the 4046/7046/9046 series,
> and to be reminded about the design tools available for them.

Well, my point was that I have seen it bite, but there is other
occasions where it doesn't bite. Still, better options can many times be
used, and many designs it can be good enough. If you use it without care
and knowledge, beware. That goes for any tool we apply, so bringing up
attention is already there a step on the way.

Cheers,
Magnus
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Re: [time-nuts] 4046 replacement

[Charles Steinmetz]

Alexander wrote:


but as I wrote a while ego ADI has a bit different chip which is free of
dead zone and much faster


Hell, there are literally hundreds of PLL chips, lots of them better at 
various things than the 4046.  I did not suggest that the 4046/7046/9046 
is the best PLL for any particular purpose (and I did say I rarely use 
them).  My points were just (i) that the 4046 doesn't perform as 
terribly as a lot of people seem to think if you know a few easy tricks, 
and (ii) that the 9046 is better on all counts without the need for such 
tricks.


It seems that lots of people like the 4046 series chips (including the 
7046 and 9046), partly due to familiarity, partly because there are 
thousands of published circuits that use them and not everybody wants to 
completely redesign circuits that are already known to work, and 
certainly because they are dirt cheap (unlike the fancier Analog Devices 
parts, some of which are quite pricey).  I thought these folks might 
like to know how to optimize performance with the 4046/7046/9046 series, 
and to be reminded about the design tools available for them.


Charles


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Re: [time-nuts] 4046 replacement

[Alexander Pummer]

but as I wrote a while ego ADI has a bit different chip which is free of 
dead zone and much faster, I used it for low phase-noise clock generator 
for 3,1Gb/s fiber optic systems of C-Cor/Comlux in the end of the past 
century, now I am on vacation and do not have my engineering note books 
with me, but 1) I already posted it in the past 2) I will post it again 
after I returned home,

73
KJ6UHN
On 5/6/2018 1:03 AM, Charles Steinmetz wrote:
See below for further information on working with the 4046/7046/9046 
PLL families, including must-have design tools for anyone designing 
with these devices.


I wrote:


The "flaw" in the 4046 is a dead zone around zero error in Phase
Comparator 2 (the PC one generally uses).


Magnus responded:


It is very bad indeed. Someone chose to use the 4046 to lock up a 155,52
MHz VCXO to a 8 kHz reference, using a 4046 as a core. The charge-pump
was then "accelerated" with a supposedly better charge-pump with a ton
of passives. Turns out that the dead-band was still there to haunt the
designers. The 155,52 MHz was further multiplied to become the 2,48832
Gb/s clock, and as they measured this they had problems with the
jitter/wander of it


Of course the dead zone was still there -- it is built into the 
4046/7046 phase comparator, and nothing you do after-the-fact can 
eliminate it (but see below re: linearizing the 4046/7046 phase 
comparator). Most of what is wrong with the circuit you describe above 
is simply bad system design, not any fault of the 4046.


While it is true that some people call the PC2 output of the 4064 a 
"charge pump," as a voltage source it is, at best, a very poor one. 
The 9046 has a real, current-mode charge pump with tri-state outputs. 
The attached charts show the difference in linearity [1].


There are tricks one can pull to linearize the PC2 output of a 4046 or 
7046.  In particular, (i) injecting current into the PC2 output node 
biases the detector away from the dead zone at the price of a static 
phase error, and (ii) instead of using a passive RC filter, run the 
PC2 output through the resistor to the virtual-ground input of an 
active filter, which effectively turns the PC2 voltage output into a 
bipolar current output.  Still, however, the 4046/7046 PC2 cannot 
overlap positive and negative steering pulses as the 9046 PC2 can, and 
the 9046 thresholds are established by a real voltage reference, so 
the 9046 will always be better than the best that can be done with a 
4046 or 7046.


I do not use 4046-type devices very often, but ever since the 9046 
became available I have used it exclusively in preference to the 4046 
and 7046.


Best regards,

Charles


[1]  The attached charts are taken from the Philips CMOS PLL 
Designer's Guide (1995), which is an absolute must-have for anyone 
designing with the 4046/7046/9046 PLL families.  List member Daniel 
Mendes pried the Guide and supporting files out of Philips a couple of 
years ago, and list member Oz from DFW hosts them on his site.  I 
cropped the pages of the Design Guide to eliminate the large white 
borders and re-posted it all as a zip file to Didier's site: 
. 
Enjoy!




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Re: [time-nuts] 4046 replacement

[Charles Steinmetz]

See below for further information on working with the 4046/7046/9046 PLL 
families, including must-have design tools for anyone designing with 
these devices.


I wrote:


The "flaw" in the 4046 is a dead zone around zero error in Phase
Comparator 2 (the PC one generally uses).


Magnus responded:


It is very bad indeed. Someone chose to use the 4046 to lock up a 155,52
MHz VCXO to a 8 kHz reference, using a 4046 as a core. The charge-pump
was then "accelerated" with a supposedly better charge-pump with a ton
of passives. Turns out that the dead-band was still there to haunt the
designers. The 155,52 MHz was further multiplied to become the 2,48832
Gb/s clock, and as they measured this they had problems with the
jitter/wander of it


Of course the dead zone was still there -- it is built into the 
4046/7046 phase comparator, and nothing you do after-the-fact can 
eliminate it (but see below re: linearizing the 4046/7046 phase 
comparator). Most of what is wrong with the circuit you describe above 
is simply bad system design, not any fault of the 4046.


While it is true that some people call the PC2 output of the 4064 a 
"charge pump," as a voltage source it is, at best, a very poor one. The 
9046 has a real, current-mode charge pump with tri-state outputs. The 
attached charts show the difference in linearity [1].


There are tricks one can pull to linearize the PC2 output of a 4046 or 
7046.  In particular, (i) injecting current into the PC2 output node 
biases the detector away from the dead zone at the price of a static 
phase error, and (ii) instead of using a passive RC filter, run the PC2 
output through the resistor to the virtual-ground input of an active 
filter, which effectively turns the PC2 voltage output into a bipolar 
current output.  Still, however, the 4046/7046 PC2 cannot overlap 
positive and negative steering pulses as the 9046 PC2 can, and the 9046 
thresholds are established by a real voltage reference, so the 9046 will 
always be better than the best that can be done with a 4046 or 7046.


I do not use 4046-type devices very often, but ever since the 9046 
became available I have used it exclusively in preference to the 4046 
and 7046.


Best regards,

Charles


[1]  The attached charts are taken from the Philips CMOS PLL Designer's 
Guide (1995), which is an absolute must-have for anyone designing with 
the 4046/7046/9046 PLL families.  List member Daniel Mendes pried the 
Guide and supporting files out of Philips a couple of years ago, and 
list member Oz from DFW hosts them on his site.  I cropped the pages of 
the Design Guide to eliminate the large white borders and re-posted it 
all as a zip file to Didier's site: 
. 
Enjoy!


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