[Dspforum] demodulator performance/frame synchronization

[michael norris]

Instructors/students,

Can we assume that a frame begins on an 8 (f_sample/f_symbol) sample
boundary? In the general case, I don't think we can. If we can't, then it
seems we need to compute an 8-point FFT per sample in order to synch the
frame.

Once we've synched on the frame, we could then compute the FFT once per 8
samples. Then we would benefit from interleaving the sampling and
computation with EDMA. But if our computation time must already be under one
sampling time, then what benefit is there to implementing EDMA with this
lab?

(Maybe it prevent us from missing data during the printf() call. But do we
care about this?)

Could someone add a little more about detecting the frame boundary? Assuming
we are sampling once-at-a-time to do the synchronization, where in the start
bit's 8 samples do we fall? Are we one past the half-way sample, i.e. sample
5/8?

We should have plenty of time to do our 8-point FFT with this board. I'm
just curious where EDMA could benefit us here.

Thanks,
-Michael
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