I have this (very smart) semi-retired design engineer friend named Craig who I
first queried about this clock issue.
We always enjoy getting together in his lab or sitting outside enjoying the
weather and good cigars.
As usual I bug him with my crazy ideas as a way to educate myself or
If the heart of your clock is a micro, you may be able to reset the
processor and set the time once a second fastest enough not to have any
visual artifacts. Even if you have a perfect 32.768 kHz clock you still
have to set the phase (time) manually and deal with DST, leap seconds,
and power
e the goal is 32 kHz output.
/tvb
- Original Message -
From: "Jim Harman" <j99har...@gmail.com>
To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com>
Sent: Friday, October 21, 2016 10:42 AM
Subject: Re: [time-nuts] 1PPS to 32.768 kh
I'm kind of late to the party on this one, but I think the simplest
approach with the least disturbance to the operation of the original
system would be to form a VCXO and PLL.
Good old 4000 series CMOS stuff should be plenty fast enough. Two pieces
should be sufficient. For example, a CMOS
On Thu, Oct 20, 2016 at 7:08 AM, Bob Camp wrote:
> One problem with a PLL and a 1 Hz input are the values of components
> you get in the loop.
> The other issue is the cost of the VCXO that will get
> you to 32,768 KHz.
>
As I mentioned earlier, the DS3231 chip (about $6.50 qty 1
On Wed, Oct 19, 2016 at 8:32 PM, Lee - N2LEE via time-nuts <
time-nuts@febo.com> wrote:
>
> A lot of my other clocks are 6 digit NTP POE clocks so they are not GPS
> accurate but I would at like them to all agree.
>
Can you point all of those POE NTP clocks to a common LOCAL NTP server?
Time
Hi
One problem with a PLL and a 1 Hz input are the values of components
you get in the loop. The other issue is the cost of the VCXO that will get
you to 32,768 KHz. The PLL as described by the OP would need the 1 pps
divided by 2 with a lot of PLL chips. You now are locking 32768 to 0.5 Hz.
I think the suggestion to simply blast out 32768 pulses once per second at
a fast rate of (say) 40kHz is the simplest yet and VERY close to what the
OP asked for. This makes the average frequency near perfect but of cours
with HORRIBLE phase noise but the OPonly cares about average frequency.
To: "time-nuts@febo.com" <time-nuts@febo.com>
> Subject: [time-nuts] 1PPS to 32.768 khz
>
> Here's another way to do it for a wall clock display... set up an
> oscillator/divider (or even a 555 timer) to generate a frequency close to,
> but faster than 65536 Hz.Setu
Tom nailed the issue.
First problem is I was native in thinking “Oh this will be easy to interface to
the NTP or GPS”. WRONG :)
But the good news I am learning a lot about accurate time from you guys.
The second issue is Tom is right. This is a cheap jumbo clock that at the heart
uses a
I was thinking 32.768kHz VCXO and phase detector to make a simple
analog PLL. I found a datasheet for a suitable VCXO and assuming a
total error of 20ppm, it would only need to be divided by 2 to prevent
locking to the wrong frequency making an analog PLL pretty simple.
Safer to divide by 4 or 16
iginal Message -
> From: "Brooke Clarke" <bro...@pacific.net>
> To: "Lee - N2LEE" <l...@n2lee.com>; "Discussion of precise time and
> frequency measurement" <time-nuts@febo.com>
> Sent: Wednesday, October 19, 2016 12:18 PM
> Subject: Re:
> Here's another way to do it for a wall clock display... set up an
> oscillator/divider (or even a 555 timer) to generate a frequency close to,
> but faster than 65536 Hz.Setup a 16 bit counter clocked by that signal.
> When the 1PPS signal arrives, start the counter. After 65536 pulses
HI
That approach would also work fine on a “internal clock” MCU. Scratch the need
for a fancy timer. You may
be down under 50 cents ….
Bob
> On Oct 19, 2016, at 7:15 PM, Mark Sims wrote:
>
> Here's another way to do it for a wall clock display... set up an
>
Here's another way to do it for a wall clock display... set up an
oscillator/divider (or even a 555 timer) to generate a frequency close to, but
faster than 65536 Hz.Setup a 16 bit counter clocked by that signal. When
the 1PPS signal arrives, start the counter. After 65536 pulses the
Hi
As has been already mentioned, a lot depends on what you have. The drop dead
cheapest way to do it:
Start with an MCU with an internal oscillator. There are *lots* to pick
between. Which sort really does not matter.
For example, I’ll use one that starts at 4 MHz.
Divide the 4 MHz down to
/tvb
- Original Message -
From: "Brooke Clarke" <bro...@pacific.net>
To: "Lee - N2LEE" <l...@n2lee.com>; "Discussion of precise time and frequency
measurement" <time-nuts@febo.com>
Sent: Wednesday, October 19, 2016 12:18 PM
Subject: Re
Hi Lee:
32768 can easily be divided down to drive the clock. So why not bypass the 32768 and drive the clock directly from the
1 PPS you now have.
http://www.prc68.com/I/QuartzClk.shtml
--
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The
Even if the micro controller had to directly control the LEDs on the clock
your suggestion would be not only simpler bot several orders of magnitude
more accurate.I'd guess that a first attempt to build a 32KHz GPSDO
would not be perfect but the PPS signal is effectively dead-in perfect in
On Wed, Oct 19, 2016 at 6:15 AM, Dave Martindale
wrote:
> If the "big digital clock" doesn't display the time with fractional-second
> precision, then it only needs to be updated at 1 Hz, which can be done with
> the 1 PPS directly. Consider replacing the 32 kHz
asurement" <time-nuts@febo.com>
Cc: <hmur...@megapathdsl.net>
Sent: Wednesday, October 19, 2016 3:29 AM
Subject: Re: [time-nuts] 1PPS to 32.768 khz
>
> davidwh...@gmail.com said:
>> I think a PIC might be fast enough to DDS it. The output bandpass filter
>> will
You guys are great. I especially like the more creative solutions that could
take this project to a different level.
I should have known that my request was not a simple one. :)
While going from 1 PPS to 32.786 is not as easy as I had hoped what I find odd
is that others must have been
looking
Hi,
=
If you want to go Tom's picDIV route, and are lazy like me, this is one
of several boards available.
https://oshpark.com/shared_projects/kXG6K5Xu
You'll get several copies of the bard board for under $10. Few minutes
stuffing it, and you'll have a working device...
Dan
Hi Lee,
@febo.com
Subject: [time-nuts] 1PPS to 32.768 khz
First let me say this is first time I have posted to the group so go easy on
me. :) Secondly I want everyone to know that you guys make me feel so NORMAL
for wanting to use and understand accurate timing devices.
I thought there was something seriously
If the "big digital clock" doesn't display the time with fractional-second
precision, then it only needs to be updated at 1 Hz, which can be done with
the 1 PPS directly. Consider replacing the 32 kHz crystal, divider chain,
and microprocessor with a new microcontroller that takes 1 Hz input and
Lee,
Another option might be something like this:
http://qrp-labs.com/progrock.html
it is a standalone ATTiny based device which uses a plug in Si5351a
synthesizer. Output frequencies from as low as 3.515 khz to a 100+ MHz
can programmed and can be GPS disciplined suing a GPS' PPS. There are
davidwh...@gmail.com said:
> I think a PIC might be fast enough to DDS it. The output bandpass filter
> will cure a lot of sin. Using a dedicated switched capacitor filter would
> be fun but more expensive.
There are two parts to a DDS like setup. One is the math for the DDS and
then
First let me say this is first time I have posted to the group so go easy on
me. :)
Secondly I want everyone to know that you guys make me feel so NORMAL for
wanting to use and understand accurate timing devices.
I thought there was something seriously wrong with me now I know there are
others
2LEE" <l...@n2lee.com>; "Discussion of precise time and frequency
measurement" <time-nuts@febo.com>
Sent: Wednesday, October 19, 2016 7:26 PM
Subject: Re: [time-nuts] 1PPS to 32.768 khz
What you want is a GPSDO. Most people here build these to run at 10MHz.
But you nee
On Tue, 18 Oct 2016 22:59:42 -0700, you wrote:
>> 1. Does anyone know of a device that will take a 1PPS GPS timing signal and
>> generate a 32.768 kHz sine wave output ? I have big digital clock that uses
>> an 8 bit micro processor and an external 32.768 crystal. Obviously the
>> external
What you want is a GPSDO. Most people here build these to run at 10MHz.
But you need one that runs at 32768 kHz.
Try this: Divide the crystal oscillator's output by 32768. This will give
you one Hz. Compare the phase of this with the phase of your PPS from the
GPS. Push and pull the crystal
> 1. Does anyone know of a device that will take a 1PPS GPS timing signal and
> generate a 32.768 kHz sine wave output ? I have big digital clock that uses
> an 8 bit micro processor and an external 32.768 crystal. Obviously the
> external crystal is awful for accuracy.
I don't know of any
. The older I get, the
less I require precision time. YMMV.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Lee -
N2LEE via time-nuts
Sent: Tuesday, October 18, 2016 9:03 PM
To: time-nuts@febo.com
Subject: [time-nuts] 1PPS to 32.768 khz
First let me say
-
From: "Lee - N2LEE via time-nuts" <time-nuts@febo.com>
To: <time-nuts@febo.com>
Sent: Tuesday, October 18, 2016 7:03 PM
Subject: [time-nuts] 1PPS to 32.768 khz
First let me say this is first time I have posted to the group so go easy on
me. :)
Secondly I want everyone to know
It might be easier to go the other away around... take a GPS receiver with a
programmable output frequency and set it to produce 32768 KHz. The Venus
timing receivers can produce accurate output frequencies (but with a fair
amount of jitter, which would be irrelevant to a clock display).
Hi Lee,
It's not exactly what you asked for, but for your clock you might give this
a try, or consider using the underlying DS3231 chip directly.
https://www.adafruit.com/product/255
It is basically a much more accurate and stable than usual 32KHz
oscillator, with a TCXO that you can actually
First let me say this is first time I have posted to the group so go easy on
me. :)
Secondly I want everyone to know that you guys make me feel so NORMAL for
wanting to use and understand accurate timing devices.
I thought there was something seriously wrong with me now I know there are
others
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