METHOD OF COMPENSATING FOR LOW FREQUENCY AUDIO DISTORTION IN DIRECT FM MODULATION OF A SYNTHESIZER
Original Publication Date: 1998-Mar-01
Included in the Prior Art Database: 2002-Jun-28
Two-way communication transmitters using frequency modulation have a need to support a modulation signal bandwidth of 7 Hz to 3k Hz to allow for sub-audio signaling and voice modulation. The modulation level accuracy must be very high at low frequencies (7 to IO0 Hz) if the transmitters are used in a simulcast contiguration which has two or more transmitters operating on the same frequency. Without this high level of accuracy, the recovered audio quality would be poor in a simulcast overlap area. This overlap area is where the same frequency transmitters have nearly equal signal strength.