Fail-safe code keying transmitter

Claim 1

A fail-safe circuit arrangement for removing sharp harmonic producing portions from square wave signals prior to modulation of a carrier wave signal comprising, a source of square wave signals, an electronic switching circuit connected to said source of square wave signals, said switching circuit including a first and a second driving transistor and a first and a second driven transistor, said first driving transistor controlling the conductive condition of said first driven transistor and said second driving transistor controlling the conductive condition of said second driven transistor so that said first and said second driven transistors are alternately rendered conductive, a series L-C circuit tuned to the fundamental frequency of said square wave signals connected to said first and said second driven transistors wherein the conduction of said first driven transistor causes the leading edge of said input signals to be transformed into one-half cycle of a raised cosine wave form and the conduction of said second driven transistor causes the trailing edge of said input signals to be transformed into another half cycle of a raised cosine wave form, and a clipping modulator circuit for varying the amplitude of a carrier signal in accordance with the transformed raised cosine wave form.