Abstract: A method for tuning and aligning an electronically tuned FM broadcast receiver is described. The system described compensates for the mismatch of component values between the antenna and RF amplifier tuned circuits, and the IF offset between the local oscillator frequency and the center frequencies of the antenna and RF resonant circuits by developing independent tuning signals for the circuits. The system also provides temperature compensation, and can be aligned without mechanically adjusting inductors and/or capacitors in the tuned circuits.

Abstract: A citizens band transmitter employing negative overall envelope feedback in the final RF stage obtains the feedback signal from a filter in the antenna coupling network which has a phase shift of 90 degrees or an odd multiple thereof at the radio frequency. A pair of detector diodes have their cathodes connected to opposite ends of filter and their anodes connected to a low pass filter to provide an envelope of the higher of the two voltages at either end of the filter in the coupling circuit in negative feedback to the modulating signal.