An efficient sampling technique for sums of bandpass functions
Abstract
A well known sampling theorem states that a bandlimited function can be completely determined by its values at a uniformly placed set of points whose density is at least twice the highest frequency component of the function (Nyquist rate). A less familiar but important sampling theorem states that a bandlimited narrowband function can be completely determined by its values at a properly chosen, nonuniformly placed set of points whose density is at least twice the passband width. This allows for efficient digital demodulation of narrowband signals, which are common in sonar, radar and radio interferometry, without the side effect of signal group delay from an analog demodulator. This theorem was extended by developing a technique which allows a finite sum of bandlimited narrowband functions to be determined by its values at a properly chosen, nonuniformly placed set of points whose density can be made arbitrarily close to the sum of the passband widths.
 Publication:

The Telecommunications and Data Acquisition Report
 Pub Date:
 April 1982
 Bibcode:
 1982tdar.nasa....3L
 Keywords:

 Bandpass Filters;
 Bandwidth;
 Frequencies;
 Sampling;
 Transfer Functions;
 Channel Capacity;
 Demodulators;
 Digital Systems;
 Frequency Modulation;
 Navigation;
 Nyquist Diagram;
 Communications and Radar