Ah!
I'll take the freedom of mentioning your StackOverflow question
here:
http://stackoverflow.com/questions/37042209/receiving-data-using-aux-cable-on-gnu-radio
Because it contains an image of your receiver.
Best regards,
Marcus
On 05.05.2016 15:05, Marcus Müller
wrote:
Hi Haaris,
with "aux cable", you're referring to an audio transmission?
The point is that the symbols are always
recovered correctly, but the dynamic amount of junk recovered
before the constellation locks itself makes the pack 8 bits
block work differently. (this is what I think is happening)
Exactly! Since there's no way for the receiver to know when the
transmitter started transmitting, it decodes stuff before there's
actually anything to decode.
In essence, you need some kind of preamble or so to tell your
receiver when to start – side effect of having something like that
would be that you could correct some things (the two sound cards
don't share the same oscillator, which leads to a symbol rate
offset, and a center frequency offset).
I'm not quite sure about the right approach here; we used to have
"correlate access code", which you can just tell to look for a
specific streams of 0s and 1s, and throw away stuff before, I
think. But also, we deprecated that, because it had some
fundamental architectural drawbacks; don't know what I should
really recommend in this scenario.
Could you maybe export your flow graph (if you made it in GRC;
File->Screen Capture) and share it with us?
Best regartds,
Marcus
On 05.05.2016 03:09, Haaris wrote:
Hello all,
I am trying to transmit data using aux cable
from one laptop to another.
The modulation scheme I am using the PSK mod
block is DQPSK.
The problem is that while recovering data I have
to set a specific value of delay to recover the
original data back.
Sometimes no delay is needed, while at times some
constant value is needed.
The point is that the symbols are always recovered
correctly, but the dynamic amount of junk recovered
before the constellation locks itself makes the pack 8
bits block work differently. (this is what I think is
happening)
Is there a workaround or a simple way to fix this
problem e.g dynamic delay of some type?
Any help will be appreciated.
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