Hello,
Does anyone have an EXCEL spreadsheet that calculates the individual phase
noise of 3 oscillators when they are compared against each other, e.g A vs
B, A vs C, B vs C.
I.e the 3 corner hat technique.
I do have a Timepod and I thought Timelab could do that, have haven't found
how
Hi,
You have too many 1s in your startup string compared to the expected PRS_10\r.
If the MCU clock is not 10Mhz then the integrated UART rates will be off,
which should produce framing errors, but do UARTs still detect and systems
report these nowadays, or just pass along garbled data?
Hi,
Not sure if it is interesting for you guys but I wrote a simple program
for e.g. Linux (or any other system with the pps api implemented) that
listens on a pps source waiting for a pulse and then toggles a gpio
pin. That way you can measure the latency introduced by the the kernel
when
brayn...@gmail.com said:
Shortly after power is applied to the PRS10, I do get a string of
characters. Believe it should be the model information. Instead I get:
wy+VPgy
One opportunity for confusion is an extra or missing inverter. Does the
start bit have the correct polarity?
I would
Looking at the data expected and received on the wire, there could be an extra
inversion after some bits delay until an inverted 1 is detected as a start bit:
1101 0011 00110001 0101 01010011 01010010 0101 .01_SRP - what
you should see on your scope
0001 01100111 0101
Hang on a minute, polarity does not switch all of a sudden.
The standard RS-232 interface chips include an inverter. The normal output
from serial pins on microprocessors or PCI/USB serial chips expects that
inversion.
For short runs where you are designing both ends, it's common to skip the
What are you measuring? Seriously. What is it you need to know, is it?
1) The time between the raising edge of the PPS and when the OS samples the time
2) The time it takes between the PPS edge and when a user land process
is notified.
There are other things you can measure but if you want to
Hi -
So I took the time tonight to poke at things with the scope. Hopefully it
will be of interest.
First off, I probed the MCU (MC68HC11) TX line directly. And, it looks like
I misstated in my last mail. The MCU itself is 5V TX idle TTL Serial. On
the unit's output, it is inverted and 0V idle.
I tried through the weekend, double and triple checking wiring and setup.
I've tried the following methods of getting serial comms working:
PRS10 - Arduino Uno (with processor bypassed) - USB Host
PRS10 - Level Shifter - BBB UART
PRS10 - MAX232 - USB Serial adapter
Shortly after power is applied
Real time nuts use Comet Cleanser to raise their xtal frequency and a graphite
pencil to lower it. Only crystal cretins would use toothpaste ;-) All my
FT-243's are more acc'rit than those new-fangled silly slezium and rubitinium
oscillators and masery thingamabobs. Geeze, them youngin's
The earlier suggestion of a missing inverter seems to be the right thing to
chase this evening. I was able to add an inverter and decode the first few
characters on a scope. I get the expected DC1-CR-P-R-S sequence.
Thanks for the input on this. I'll reply back after I've had more time to
hack at
This is from 3hat.c -- C code, but you get the idea:
A[i] = sqrt( (0 + SQUARE(AB[i]) - SQUARE(BC[i]) + SQUARE(AC[i])) / 2.0
);
B[i] = sqrt( (0 + SQUARE(AB[i]) + SQUARE(BC[i]) - SQUARE(AC[i])) / 2.0
);
C[i] = sqrt( (0 - SQUARE(AB[i]) + SQUARE(BC[i]) + SQUARE(AC[i])) / 2.0
Actually, after typing all that, it occurred to me that you might have actually
meant to ask about N-cornered stability measurements. They aren't supported by
the current official release of TImeLab; you need to use the beta version from
http://www.miles.io/timelab/beta.htm .
For
Hi Folkert
If you have a board with a hardware timer that supports load/match/compare
then you can schedule an external interrupt to be generated at a
predetermined point in the hardware count. Thus, if you know the transform
between your disciplined clock and the hardware counter of the timer
FYI, if you have an FTDI USB/Serial dongle you can use the FTDI FT-Prog
utility to reprogram the chip to invert polarity from normal. I did that
with my 'Arduino' USB/TTL cable in order to talk to an Rb osc. No need to
mess around with additional inverters. You can get the utility from the
support
On 25/08/15 18:53, Andrew Symington wrote:
Hi Folkert
If you have a board with a hardware timer that supports load/match/compare
then you can schedule an external interrupt to be generated at a
predetermined point in the hardware count. Thus, if you know the transform
between your disciplined
One nice thing about phase noise is that it's computable with complex FFTs,
rather than the one-dimensional phase or frequency differences that ADEV uses.
Another nice thing is that it's stationary -- meaning its probability
distribution can (usually) be treated as unchanging from one
17 matches
Mail list logo
