Single stage power amplifiers for multiple signal channels

Claim 1

Apparatus for amplifying a plurality of audio information signals by means of a common power amplifying stage, comprising: a. a plurality of modulating means each operating at a separate carrier frequency and having a separate output, each separate one of said modulating means associated with one of said audio signals for providing a plurality of separate modulated signals each representative of one of said audio signals and differing one from the other by said carrier frequency, b. power amplifying means having an input terminal and an output terminal, said input terminal including means for coupling each of said output tErminals of said modulating means to said input terminal of said power amplifying means to provide at said output a composite signal representing the combination of all of said modulated signals, c. a plurality of discriminator circuits, each associated with a separate one of said modulated signals each of said discriminator circuits having an input coupled to said output of said power amplifying means and an output for providing thereat said associated audio information signal, d. a plurality of utilization means each separate one coupled to one of said discriminator output circuits, e. scanning means operative to provide a plurality of waveforms at a plurality of separate outputs, each of said waveforms having the same repetition rate which rate is relatively higher than any frequency component contained in said audio information signals, and each having a predetermined signal duration and a specified delay between each waveform, and f. means coupling a separate one of said outputs to one of said utilization means to cause said utilization means to utilize said discriminator output signal only during said predetermined signal duration.