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I was expecting two symmetrical lines (well apart) and more towards the edges than the centre.
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I did not take the pictures with the lines on the right side, but actually I do have the two lines toward the edges.
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your truncation of 29 bits by taking bit 19:12 is not clear to me.
You should be taking the value from MSBs. unless they are "dead" bits i.e. never used by result(indicating low input swing or bad design)
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I noticed that the results never get up pass bit 19. That's why I'm truncating them.
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another issue that popped up now is the way you display on the monitor. You must latch your fft output while refrshing the monitor otherwise a free running fft will not give identical block data unless you work hard to do that
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Isn't it good enough to have the dual-port RAM where the FFT is writing its output to it, and the monitor is reading from it?
I just thought of something else that might cause the lines to fluctuate...
It has to do with my ADC setup. The ADC is outputting the digitized data for the left and right channels alternatively on the same bus, i.e. multiplexing the data. I am de-multiplexing the ADC output to Left and Right channels, but only passing the Left channel data to the FFT. Is it right to say that half of the time the FFT is getting zeros? Hmm, may be the FFT is just using the same left channel data twice because it is latched? What should be the correct way of doing this? Should I pass one channel to the FFT real input and the other channel to the imaginary input?
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