On Tue, Nov 13, 2012 at 10:43 AM, Zhiwen He <hey...@gmail.com> wrote:
> hello all, > > > When I use the fft blcok, it seems not right. > > I build the test system like this: Square source -> IFFT -> FFT -> File > Sink, when the input is 1, the output in the file sink is 1, and when the > intput is 0, the output is random, sometimes 0, sometimes between -1 and 1. > > Like this: > > input: > > > > > > > > 0 0 0 0 0 0 0 > > > > > > 0 0 0 0 0 0 0 > > > > > > 0 0 0 0 0 0 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 0 0 0 0 0 0 0 > > > > > 0 0 0 0 0 0 0 0 > > > > > 0 0 0 0 0 0 0 0 > > > > > 0 > output: > > > > > > > 0 0 0 0 0 0 0 > > > > > > 0 0 0 0 0 0 0 > > > > > > 0 0 0 0 0 0 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > 0 > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 0 > > > > > 0 > > > > > 0 > > 0 > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > 0 > 0 0 > > > > > 0 > 0 > 0 > > 0 > > > > > 0 > 0 > > > > 0 > > > > > 0 > > 0 > 0 > 0 > > > > > 0 0 > > > 0 0 0 > > > > > 0 0 > 0 0 0 > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > > 0 > > > > > 0 > > > > > 0 0 > > > > > 0 > > > > > How should I do, so that the source data is the same as the sink data? > > Thanks. > > Heyutu > Hi Heyutu, I just tried this right now and don't have a problem. This is my full graph: sig_source (square wave) -> throttle -> stream_to_vector(fftsize) -> fft(fftsize, reverse) -> multiply_const(fftsize*[1/fftsize], fftsize) -> fft(fftsize, forward) -> vector_to_stream -> time sink Tom
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