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This article shows the analysis of Vestigial Side Band Suppressed Carrier demodulation.

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I have understood the mathematical derivation up to eq (1). However, I am unable to understand which components in eq (1) are to be retained and which are to be filtered out and the reasoning behind it. I understand that in VSBSC modulation, along with one sideband, some portions of the other sideband (vestige) are also included while transmitting.

Please help me understand, which terms are to be retained and which terms are to be filtered out in case of Vestigial Side Band Demodulation.

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  • \$\begingroup\$ Only those components around f=0 are of interest. Everything bigger is attenuated. All energy at larger f must be removed. \$\endgroup\$ – KalleMP Apr 9 '18 at 14:55
  • \$\begingroup\$ @KalleMP Sir, understood. Sir, I would like to ask another thing regarding spectrum which is: How would the spectrum of $M(f)H(f-f_c)$ look like? or How would the spectrum of $M(f-2f_c)H(f-f_c)$ look like? If we had to draw them on paper how we would draw them? \$\endgroup\$ – Anwesa Roy Apr 9 '18 at 15:30
  • \$\begingroup\$ @KalleMP Sir I think it could be done the following way: We have to first draw the spectrum of $M(f)$ and $H(f-f_c)$ separately and then multiply the two frequency domain signals. Sir if you get some free time would you please draw the spectrum of eq (1) and upload it. Thank you. \$\endgroup\$ – Anwesa Roy Apr 9 '18 at 15:34
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It is passed through a low-pass filter (LPF), which means only low frequencies will pass through and higher frequencies will be filtered out. In this case, "2fc" terms are higher frequencies, so they will be filtered out.

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