On Tue, Jun 30, 2015 at 08:11:08AM -0700, Peter Shipley wrote: > > Was it the harmonics that prevented the hackrf from transmiting then > ?
I doubt it. The harmonics themselves probably do not have any harmful effects other than making you a worse neighbor on the spectrum. However, the harmonics are symptoms of abrupt transitions between frequencies in your generated waveform. These transitions may cause problems with the receiver, but it depends on how the receiver is implemented. The best way to avoid them is to use a Numerically Controlled Oscillator as John suggested and to use a pulse shaping filter. The typical goal is to produce a waveform continuously varying phase. On the other hand, the frequency transitions in the captured waveform are also fairly abrupt, so I'm guessing that your receiver doesn't care about phase discontinuities. > Oddly when eyeballing the data and gnuplot the data looks almost > identical except for my data being perfectly centered, the higher & > low frequency are exactly the same but for the phase shift. There are several things different between your generated waveform and your captured waveform. Here are the ones I've noticed (with a guess at the order of importance): 1. inversion of bits 2. verification that every bit is correct 3. lack of repetition 4. total duration 5. frequency offset (may be correctable with hackrf_transfer -f) 6. abrupt transition between frequencies Mike _______________________________________________ HackRF-dev mailing list [email protected] https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
