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Re: [Discuss-gnuradio] Delay block controlled by input

From: Carlos Alberto Ruiz Naranjo
Subject: Re: [Discuss-gnuradio] Delay block controlled by input
Date: Wed, 8 Oct 2014 12:29:08 +0200

Sorry, I have explained bad: S
I have the signal saved in a file and 10230000 samples are one second (in the real world).

In the first graph I have two clocks (counters samples). When passing 102300 samples it increase 0.01 seconds.
In the first watch this time controls the position of the satellite and his delay in this time. It allows to know what signal time is passing in the delay block.

But I have a problem: clock 2 (a test clock) and clock 1 haven't the same time; it has a drift.

Then, I must use clock 2 (
count the samples in the delay block output, not input). But it creates a loop.

2014-10-08 12:07 GMT+02:00 Marcus Müller <address@hidden>:
Hello Carlos,
On 08.10.2014 09:10, Carlos Alberto Ruiz Naranjo wrote:
> I generate the signal from a file (10230000 samples/s) to a file. My
> sampling clock drifts significantly :S
No. Unless I misunderstood you, you have a big misconception:
"sampling clock" is *not* the rate at which your samples pass through
your processing chain (ie. GNU Radio). It is the time base at which they
are measured, or simulated to, mathematically.
The device/software that actually captures the samples and saves them
has a fixed clock. If that clock changes too much a) compensate that in
software, if possible or b) get a better device.
This is digital signal processing. Real world time has *no* meaning
here, everything is measured relative to the interval between two
sampling times. You can process the signal as fast or slow as you want
to (as long as that doesn't lead to things like overflows), and nothing
in the processing chain should care.
> - Picture one: Counter Clock 2 is correct but Counter Clock 1 no.
> Then I should use the second configuration, but it is not allowed because I
> have a loop, right?
I don't understand your graph, sorry :(


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