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From: | Kresimir Dabcevic |
Subject: | [Discuss-gnuradio] Strange behaviour in GRC for a simple FFT/IFFT flow-graph |
Date: | Thu, 7 Nov 2013 10:19:35 +0100 |
Hi all!
When constructing a simple flow graph Signal_source(f)->Throttle(f)->Stream_to_vector(vf)->Forward_FFT(vc)->Reverse_FFT(vc)->Vector_to_stream(c)->WX_GUI_FFT_sink(c), the sink exhibits strange behaviour, showing frequency (and the image frequency) different than the one I'm creating with the signal source, e.g. for f=1kHz, sink shows 15kHz and -15kHz whereas for f=15 kHZ it shows 1kHz and -1kHz. On the other hand, if I create a complex signal using signal source, or use Float_to_complex block before feeding it to Stream_to_vector, the results are as expected. Is this a glitch in GR (I'm using GRC 3.6.4.1.), or is there something I'm missing here? The flow graph and the result for f=1kHz are as follows: *f=float; vc=vector of complex; c=complex Thanks in advance! |
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