|Subject:||Re: [Discuss-gnuradio] Transmission using Aux cable|
|Date:||Thu, 5 May 2016 15:05:51 +0200|
|User-agent:||Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0|
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?
On 05.05.2016 03:09, Haaris wrote:
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