Re: [Discuss-gnuradio] The sinusiodal waveform is drifting from input to output.

[Johnathan Corgan]

On Thu, Mar 4, 2010 at 06:59, Tom Rondeau <address@hidden> wrote:

> A fun thing to do on the USRPs is to blow on the crystal while it's
> transmitting. If you transmit a tone with usrp_siggen.py and receive
> it using usrp_fft.py with a high decimation rate (so you're only
> looking at a fairly small frequency window), you can see the effects
> that temperature makes in the oscillator's operation. You should see
> the tone in the FFT window swing left or right and the come back to
> settle on a nominal frequency.

One of the demos in my GNU Radio training course during the
bit-error-rate testing lab is to spray the transmitter crystal with
Duster or other cold spray.  The BERT receiver continuously displays
the calculated frequency and timing offset, so the transient becomes
very obvious, yet the carrier and symbol timing loops deal with it
just fine.

Johnathan