Abstract: The invention enhances the ability of rear seat passengers in a vehicle to hear the speech of a front seat occupant. Two spaced microphones in the front seat area pick up speech signals which are differentially amplified and filtered in a bandpass filter and at least one notch filter. The filter signals are reproduced through speakers in the area of the rear seat. Differential amplification of the microphone signals results in greatly reduced acoustic feedback from the speakers to the microphones. The communication system of the invention is highly integrated into other communication and audio systems in the vehicle.

Abstract: A tape recording apparatus in the form of a modified VCR is employed to record broadcast signals received by an antenna while moving through a radio-broadcast reception area. The recorded signals are maintained in an undetected, modulated-carrier form so that played-back signals from the VCR can be coupled to a radio receiver in a fixed location for testing under mobile conditions. A commercially available VCR is modified to avoid modulating FM signals by frequency a second time.