Hi,
On 09/27/2015 02:04 AM, Bob Camp wrote:
Hi
If you digitize the beat note it’s fairly simple:
The beat note is not really a sine wave. It’s periodic, but not a pure sine. The
reason is fairly simple. The frequency changes as the beat note changes the EFC.
You have a lower frequency as it
Thanks,
Yes, apologies, I didn't look at the schematic, just the text of
message. Makes more sense.
I'm looking at using a Neo7 GPS with the output set to something. I
gather that an integer divider gives the least jitter so will probably
be set 8Mhz and divide that by 8 to give 1MHz at 50%
Good question Will.
First, it divides the 10 MHz down to 1 MHz, so the oscillator would have to
be off by 10 Hz for it to lock onto the wrong cycle.
Second, the full implementation also feeds 5 MHz from the oscillator into
one of the processor's counters and checks the count every second. It
You missed the part about the 10MHz being divided by 10 million
to produce a 1PPS signal that is compared to the second 1PPS signal...
-Chuck Harris
Will wrote:
Hi,
I'm new and trying to get to grips with things.
If I understand correctly, please forgive if I have it wrong, This
locks a
On Sat, Sep 26, 2015 at 9:54 AM, Magnus Danielson <
mag...@rubidium.dyndns.org> wrote:
> If you have an oven, it is wise to discard beat-note frequencies outside
> of some suitable range, so that it first needs to go within that range
> before any attempt to lock it is done, so that worst part of
mag...@rubidium.dyndns.org said:
> Another method would be to measure the phase-detector beat-note frequency
> (most have mixer-like behavior), which you should be able to measure with
> quite good precision, then set the EFC accordingly and then close the loop.
How do you get the sign out of
Hi Hal,
On 09/26/2015 11:47 PM, Hal Murray wrote:
mag...@rubidium.dyndns.org said:
Another method would be to measure the phase-detector beat-note frequency
(most have mixer-like behavior), which you should be able to measure with
quite good precision, then set the EFC accordingly and then
Hi
Why not do a FLL based on the counter and let the TDC run at 5 MHz (with 5X
the resolution)?
It’s reasonable to believe that if you run the FLL for a while you will get
things
quite close. That should allow you to run the TDC at 10 MHz.
Bob
> On Sep 26, 2015, at 7:22 AM, Jim Harman
Hi,
Another method would be to measure the phase-detector beat-note
frequency (most have mixer-like behavior), which you should be able to
measure with quite good precision, then set the EFC accordingly and then
close the loop.
If you measure for sufficient time, and fail to detect a
Hello All,
Thank you for all the answers. I have been experimenting relentlessly with
phase detectors, and finally I came up with a circuit that will isolate
lagging and forward pulses.
So, if signal is lagging the compare, it will send one pulse from the
output of the first flip flop. If the
Hello All,
Of course I could not wait for tomorrow, so built and tested the phase
comparator that I mentioned in my previous email. (with a change)
I hooked up the output (labeled 4 and 5) to my scope, and introduced a very
small phase difference between clocks,
and I get tiny tiny pulses
Hi
If you digitize the beat note it’s fairly simple:
The beat note is not really a sine wave. It’s periodic, but not a pure sine.
The
reason is fairly simple. The frequency changes as the beat note changes the EFC.
You have a lower frequency as it gets closer to the “zero frequency”.
The net
Hi,
I'm new and trying to get to grips with things.
If I understand correctly, please forgive if I have it wrong, This
locks a 10MHz signal to a 1Hz (1pps) signal. What makes it lock to 10
000 000Hz instead of 999 999Hz or 10 000 001Hz? Just the hope that the
10MHz is exactly that?
Cheers,
To further demonstrate the Diode - R- C- approach, here (hopefully) is a
screenshot of the raw DAC output vs time on my Arduino Micro (32u4) based
system. For this test the oscillator is free running with an error of about
1 usec per 460 sec or 2.17x10^-9. The horizontal scale is 125 sec/div
Hi Can,
I suppose your circuit will work as you describe, but the diode-R-C network
at the output of the HC4046 followed by an A/D converter works fine if your
application is to lock an oscillator to a reference and you don't care if
there is a constant time (phase) difference between the two
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