Re: [Discuss-gnuradio] How to reduce reconfiguration latency

[Bolin Hsu]

Hi Marcus,

Thanks for reply. Let me try to answer the questions.

Yes. The signal frequency shifted by +/- 5%. 

The transfer burst is constant.

The frequency shift remains constant during a burst. So I estimate the shift in the beginning of a burst, and fix the setting of demodulator and resampler over the whole burst. I use FFT and interpolation to estimate the frequency shift. 

The "estimate frequency shift then configure demodulator" approach works, except it takes 600-700 ms for the demodulator to start outputting meaning data after receiving correct configuration. I call this 600-700ms time the reconfiguration latency. 

Maybe I used wrong term. By reconfiguration I mean I made two function calls: one is the set_frequency of signal source, the other is set_resamp_ratio of the fractional resampler. My data rate is 44.1k. So I lost about 30k samples when I was waiting for the reconfiguration to take effect.

Regards,

Bolin