Reason for sampling frequency being not multiple of signal frequency...

[rayan123]

I read that the sampling frequency should not be the integral multiple of signal frequency...i want to know the theory behind this..if there is any document explaining this will be great help...thanks in advance..

 

[permute]

This isn't true except when the sampling frequency is either 1x or 2x exactly. In these cases, you could end up sampling the 0 crossings every time.

Many power systems will synchronize the sampling rate to the line frequency and oversample. This allows for simple methods for computing or filtering harmonics as well as the fundamental.

 

[Mityan]

I read that the sampling frequency should not be the integral multiple of signal frequency...i want to know the theory behind this..if there is any document explaining this will be great help...thanks in advance..

This is because of harmonics. You better read about it in Walt Kester's Analog Digital Conversion (see Chapter 2, figure 2.43)