ECSE-4530 Digital Signal Processing
Rich Radke, Rensselaer Polytechnic Institute
DSP Lecture 14: Continuous-time filtering with digital systems; upsampling and downsampling: (10/20/14)

0:01:11 Review of sampling and reconstruction
0:03:04 How copies appear in the CTFT vs. the DTFT
0:05:45 Discrete-time processing of continuous-time signals
0:07:04 For a given sampling rate, how should the middle discrete-time system be chosen?
0:09:32 The effective continuous-time frequency response
0:14:24 Detailed example: digital low-pass filter
0:21:36 Cutoffs in discrete vs. continuous time
0:24:39 How are the impulse responses related?
0:28:28 Changing the sampling rate
0:31:39 Downsampling by an integer factor
0:34:56 Downsampling in the frequency domain
0:39:10 Frequency-domain sketch of downsampling (spreading copies)
0:41:20 Aliasing can occur when downsampling
0:44:34 Prefiltering to avoid aliasing
0:50:51 Side note: one can sample higher than the Nyquist rate for bandpass signals
0:56:11 Upsampling by an integer factor
0:59:52 Ideal reconstruction of the missing samples via low-pass filtering
1:01:19 Upsampling in the frequency domain
1:03:07 Frequency-domain sketch of upsampling (shrinking copies)
1:07:21 Time-domain interpolation
1:11:05 H(w) for linear interpolation

Follows Sections 11.1-11.4 of the textbook (Proakis and Manolakis, 4th ed.).

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