Electronically tuned receiver with oscillator drift correction - compares output of frequency monitor with stored output at end of channel selection operation to alter code signal

摘要

The electronically tuned reciever automatically corrects for changes in its local oscillator's frequency caused by variations in ambient temperature, power supply etc. The frequency correction system between a frequency monitor and channel selector has a first memory which holds an output signal of the monitor at the end of a channel selection operation as a reference value. A comparator compares the reference output of this memory with the output of the monitor during reception and alters the channel selector's code signal until the two outputs are the same.