A MODE-AVERAGING DIVERSITY COMBINER
STANFORD UNIV CA STANFORD ELECTRONICS LABS
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A diversity-combining technique is described which reduces frequency distortion caused by multipath propgation in high-frequency, single- or double- sideband, voice, radio transmission. By repetitively sweeping a null through the vertical polar pattern of the receiving antenna, the relative amplitude of signal components arriving by the various propagation modes is varied at a rate which is high compared with the highest audio modulating frequency. A running average of the time-varying resultant of the various mode voltages is diode rectified to extract the audio intelligence. Mode-interference-caused transmission nulls at particular frequencies in the radio spectrum are filled in by this averaging process. The technique requires no more equipment than conventinnal combining and would appear to offer superior performance.
- Radiofrequency Wave Propagation