Phase change for Transmitted Signal Bursts - The relation to clock?

GNU Radio
1

Hi,

I am transmitting a series of BPSK burst signal and try to observe the
phase distortion for the BPSK signal on air. But it is found that the
Phases of different BPSK bursts are different.
I think this change is caused by the fact that the ADC clock phases are
different for the starts of every signal burst. But I don’t know more
details on this mechanism.

BR,

–

Alex,
Dreams can come true just believe.

2

On 08/08/2013 05:25 PM, Alex Z. wrote:

Indeed, the carrier phase for discontinous transmission will be at some
random spot every time you start a burst. The hardware doesn’t have any
notion of “start the burst only when the clock phase is the same as
it was last-time I sent a burst”. Unless you have utter blind luck,
your burst timing
isn’t ever going to be an exact multiple of the clock frequency, so
there’s no way the carrier phase will be in exactly the same place at
the start of
every burst.

–
Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium

3

I just review this mail and want to ask when we try to send the burst
data,
can we force the carrier phase to be a specified value at every
beginning
of burst? If it can, does this procedure cost time or just take effect
within the sample time?

On Thu, Aug 8, 2013 at 4:53 PM, Marcus D. Leech [email protected]
wrote:

every burst.

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–

Alex,