Hi
If you are looking at time ( = the absolute offset from GPS’s version of UTC)
then
there are a number of issues.
The antenna you use will have a delay and it may well vary more than a bit. The
cable to the antenna is in the same category. If both your modules run off a
power
splitter then
Modern CPLDs often have an internal state machine that configures the chip on
power up. Not all of these shutdown the internal state machine clock after
configuration is complete. Crosstalk from the internal clock/oscillator will
modulate the output of a divider.
IIRC the Coolrunner II chips shu
Simon,
You can probably use any microcontroller as a divider, including
Atmel/AVR. Most modern processors have elaborate timer / counter / PWM /
NCO features on-chip so you can avoid the archaic cycle counting
technique used in all the PIC dividers [1].
Or you can use decade counter IC's or
Am 2022-04-30 21:33, schrieb Clint Jay:
I think the reason the PICDiv is so well regarded is because of the
specific chips used and the way the timers etc. are implemented in
them.
So, an alternate chip outside of the Microchip PIC range just might not
be
capable of the performance.
For me
I know they were unavailable from one of my usual distributors when I checked
last week. I also prefer surface mount parts and that narrows the availability
somewhat but isn't a red line for me.
I'm very open to the idea that the PIC12F was a one-off in terms of the timing
performance. But I ha
Hi Erik,
Since each Chinese GPS receiver module has its own Xtal oscillator driving
a very low power 32-bit processor usually at around 48MHz, and we can
expect these oscillators to have a slightly different frequency, let's say
the difference is 500ppm, then I would imagine there would be a
corres
I think the reason the PICDiv is so well regarded is because of the
specific chips used and the way the timers etc. are implemented in them.
So, an alternate chip outside of the Microchip PIC range just might not be
capable of the performance.
Are they in short supply?
On Sat, 30 Apr 2022 at 2
Some more info
The two GPS do keep their phase stable vs a Rb within +/-10 ns. But the
absolute time difference of their PPS pulses was, after a cold start,
stable within +/- 20ns but the average value could be up to 100ns and
differed after every cold start.
The two GPS antenna cables had a leng
The PPS jitter of a cheap Chinese GPS module was measured at about +/-
10 ns.
But the phase of the PPS compared to a Rb varied substantial more.
To verify if this was possibly due to ionospheric or atmospheric
conditions the time difference between the PPS of two identical modules
using two ide
Dear time nuts,
I'm now on this list thanks to leapseconds.com where I went looking for the
picDIV. A wonderful device. I have a project coming up where I plan to cut my
time-teeth and think a picDIV will be just right for one of the stages.
However, with components in short supply these days,
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