Pat Farrell;231181 Wrote: > So, Sean, are you sure? > > Since a square wave has infinite (to the closest approximation) > bandwidth, how can nyquist sample it? > > Unless, of course, you use an infinite sample rate. > > If you sample a 20kHz square wave at 44.1kHz, you will get a sample > than > when you feed it back through a ADC will be a sine wave at 20kHz with > a > few harmonics. > Sean is right. A true square wave cannot exist in the real world. All real-world square waves must be bandwidth limited to exist. So, one could pick a Nyquist frequency that would perfectly sample any real world square wave that could exist. (This statement was brought to you by your department of redundancy department.) If you have a 20 KHz square wave that's bandwidtch limited to 1 MHz and pick a Nyquist frequency of 22.05 KHz, you've picked too low a Nyquist limit to accurately reproduce the waveform. But if you pick a Nyquist frequency of above 1 MHz, the waveform can be reproduced exactly.
The debate should not be centered on whether sampled, bandwidth limited waveforms can be reproduced accurately; given the proper parameters, they can. Rather it should be centered about what should be the bandwidth limit and how it should be enforced. How much do components above 20 KHz matter to the average human? What are the tradeoffs involved in filter slope as the Nyquist limit gets farther from what is important to the average human? -- Timothy Stockman ------------------------------------------------------------------------ Timothy Stockman's Profile: http://forums.slimdevices.com/member.php?userid=8867 View this thread: http://forums.slimdevices.com/showthread.php?t=38596 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
