It will depend on how the rest of the radio is built up. I'm not familiar with VP9, but can I assume it's a spec on bits in a higher layer then Layer 1? Another words, you are assuming you have bits to correlate with, as opposed to wave shapes?
You're getting into the difficulties of radio design now. You need to fully understand the needs of your system to make decisions like this. You don't have bits until you've synchronized and demodulated your signal. If you require some sort of FEC, it will need block alignment before you can decode it, so the correlator will need to be in the waveshape domain. You can still use the known VP9 headers to correlate to in this cas , but you wouldn't correlate to the bit version, you would correlate to the modulated version of those headers. P.S. Please reply to the mailing list, so others can see and reply if need be. Rich On Fri, Feb 5, 2016 at 2:53 PM, Henry Barton <kw...@outlook.com> wrote: > I'm hoping to transmit a VP9 transport stream, so perhaps the predictable > headers will be enough? > > Sent from Windows Mail > > *From:* Richard Bell <richard.be...@gmail.com> > *Sent:* Friday, February 5, 2016 5:51 PM > *To:* Henry Barton <kw...@outlook.com>, discuss-gnuradio@gnu.org > > So long as you know what you're looking for in any given scenario, you can > use that to correlate to. It can be data or a preamble. If your > receiver knows the data will always be a certain way ahead of time though, > it's hard to call that data. Semantics at that point. > > Rich > > On Fri, Feb 5, 2016 at 2:44 PM, Henry Barton <kw...@outlook.com> wrote: > >> That sounds great, Richard. But I wonder, what if the useful payload >> contains that sequence by chance? >> >> Sent from Windows Mail >> >> *From:* Richard Bell <richard.be...@gmail.com> >> *Sent:* Friday, February 5, 2016 5:27 PM >> *To:* Henry Barton <kw...@outlook.com> >> *Cc:* discuss-gnuradio@gnu.org >> >> Typically a correlator is used to look for a known sequence of bits, >> so the radio can align the rest of the processing from the end of this >> known sequence. This is referred to as frame synchronization. You could use >> the correlation estimation block to implement something like this. It would >> place a tag on the stream when it finds your known sequence and you would >> then know how everything is aligned from then on. >> >> Rich >> >> On Fri, Feb 5, 2016 at 1:04 PM, Henry Barton <kw...@outlook.com> wrote: >> >>> Hi all. I've successfully written a DSSS modulator and demodulator in >>> Windows with a chip rate of 16x. It writes samples to a file that the >>> demodulator can read and despread. Before I try any practical >>> implementations, I need to know how a DSSS stream would be >>> synchronized. Assuming the transmitter and receiver were perfectly clocked >>> in unison, what stops the receiver from tuning in in the middle of a >>> byte, thus getting a nibble from the current byte and a nibble from the >>> next? >>> >>> _______________________________________________ >>> Discuss-gnuradio mailing list >>> Discuss-gnuradio@gnu.org >>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>> >>> >> >
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