Re: [LAU] Jack sample-rate

Will Godfrey <willgodfrey(a)musically.me.uk> writes: A common architecture for an SDR receiver uses a quadrature sampling detector: you mix the incoming radio signal with a pair of clocks 90 degrees apart, and sample the two resulting signals (I/Q). Some DSP then allows you to "tune in" any signal within the bandwidth that you've sampled -- if my detector's clock is running at 7 MHz and I'm sampling I/Q at 48 kHz, my SDR receiver can demodulate any signals between 6.976 MHz and 7.024 MHz (and can receive several signals simultaneously provided they're within that range of frequencies). So the advantage of sampling at a higher rate is that you can receive a wider chunk of the radio spectrum without having to retune. High-end SDR receivers have a dedicated ADC that can run at a high sampling rate, but cheap radios like the SoftRock kits (http://wb5rvz.com/sdr/) use a regular soundcard. I'm using a SoftRock RXTX with dttsp (and sdr-shell/softrig/fldigi), which uses JACK for audio IO. Running JACK at 96 kHz for this means that I can see most of the 30m amateur band at the same time... Cheers,