[Hackrf-dev] transmitting problem

[Peter Shipley]

Was it the harmonics that prevented the hackrf from  transmiting then ?

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.

would that make any difference?
On Jun 29, 2015 3:42 PM, "Michael Ossmann" <mike at ossmann.com> wrote:

> On Sun, Jun 28, 2015 at 08:49:40AM -0700, Peter Shipley wrote:
> >
> > As you may have guessed, my generated IQ stream was made with a loop
> > calling sin/cos and timing the transitions to times where I&Q can swap
> > symmetrically ( without jumping ).
> > what is then proper method for making phase transitions?
>
> One method is to smoothly lower the amplitude to zero at the transition
> and then back up to full amplitude by mid-symbol.  This is done, for
> example, in PSK31.  A simpler approach is to use an FIR low pass filter
> on your waveform before transmission.
>
> Mike
>
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