Glenn, Is your "expected" correspond to floating point or quantized model of signal processing? Quantization leads to staircase approximation of signal; difference w analog signal appears as broad band noise.
Don D.C. Backer [email protected] 510-642-5128 On Mon, 9 Jun 2008, G Jones wrote: > Hello, > I am seeing ~ 1% changes in total power in a 1 MHz PFB spectrometer channel > when I apply a test tone 20 dB above the noise in 1 MHz many channels away. > This corresponds to ~ 40dB leakage rejection between channels, which seems > lower than I would have thought for a 2-tap, 2048 point Hamming window, for > which I would expect ~120 dB rejection in voltage, so 60dB in power. I have > tried this experiment in a PFB both without rounding and with round to even > enabled, with the same result. Robert Jarnot suggested that this could be > due to intermodulation products from the test tone going through the > discretized transfer function of the ADC. Have other people experienced this > problem? Is there any way around it? It seems like this severely limits the > PFB's usefulness. > > Thanks, > Glenn >
