Sir, I tried to undersample a band limited signal which is 10.7MHz and it's bandwidth is 200kHz. I undersample the signal and got the signal into 250kHz to 450KHz range.Then I tried to low pass filter the signal(0Hz to 450kHz). But the filtered signal was distorted. My question is can I under sample a signal and L.P.F the signal in this way? Or is there a better way to do undersampling and recover the band limited signal?
Your frequency range is from 10.6MHz to 10.8 MHz, and the multiple of your sampling frequency is 350 kHz below or above 10.7 MHz. Which multiple do you use or what is your real sampling frequency? I suppose your concept mixes both possible multiples or even more than two into your "intermediate frequency" band 250...450 kHz which causes distortion.
Christoph Kessler (db1uq) wrote: > what is your real sampling frequency? The real sampling frequency is 2.5MHz. Here I attach the spectrum analyzer output, I had got.
Attached files:
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not_filtered.jpg
(200 KB)
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filtered_bandpass1.jpg
(200 KB)
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With 2.5 MHz sampling frequency you get your signal in baseband between 600 kHz and 800 kHz not 250-450 kHz. See http://angeloricotta.altervista.org/UndersamplingAR/UndersamplingARnv.htm