(under subclass 4.01) Subject matter that either sends a defined frequency beam or frequency modulates an outgoing pulse or continuous wave optical beam in order to compare the detected return frequency to the transmitted frequency for determining range calibrated frequency differences.
SEE OR SEARCH THIS CLASS, SUBCLASS:
4.09+, where frequency is detected from the mixing of coherent waves that produce an interference pattern, which includes moving or static fringes which are counted.
5.15, where optical demodulation by heterodyning or homodyning is used to reduce the processed signal frequency.
28.5, where frequency is detected from the mixing of coherent waves that produce a moving interference pattern or just a difference frequency, which is related to velocity.
