Low power consumption stereo transmitter and receiver system

Claim 1

A low power consumption, highly compact portable stereo radio transmission and receiving system for multi-channel transmission of musical signals and the like from a pair of stereo pickup stations to a nearby receiver-amplifier to provide a high fidelity stereo amplified audio output, comprising a compact portable stereo radio transmitter unit including a pair of audio processing channels each comprising an audio processing amplifier circuit having plural inputs to each amplifier circuit, said audio processing amplifier circuits each having means providing one mode of undistorted amplification, one mode of even harmonic generation and one mode of odd harmonic generation wherein even harmonics and odd harmonics respectively are added to the waveforms at the amplifier input, selector switch means coupled to each said audio processing amplifier circuits permitting selection between said three modes, a difference amplifier circuit coupled to the outputs of said audio processing channels for producing a difference output signal which is the difference between the output signals from said two channels, a first oscillator for generating a first frequency waveform, a balanced mixer circuit to which are applied said difference output signal and said first frequency waveform to produce a double-sideband suppressed carrier signal centered on the frequency of said first frequency waveform, a second oscillator including amplifier means for generating a carrier frequency signal, means for modulating said carrier frequency signal with a modulating signal combined from the outputs from said two channels and said double-sideband suppressed carrier signal including a summing amplifier receiving the output signals from both of said channels and the double-sideband suppressed carrier signal from said balanced mixer and providing a combined output which is applied to said second oscillator to modulate the carrier frequency signal, divider means receiving said first frequency waveform for producing a pilot signal having a frequency which is one-half the frequency of the first frequency waveform, means for applying said pilot signal to said summing amplifier to be combined with output signals from both of said channels and said double-sideband suppressed carrier signal including low pass filter means connected to the output of said divider means for removing the harmonic content of said output from said divider means, and antenna means coupled to the modulated carrier frequency signal for radiating the same to the receiver-amplifier coupled to the transmitter only by a radio link.