Importance

Loading Importance Indicators...

Abstract

A signal amplitude shaping circuit is interposed between a signal source and a signal input terminal of a frequency modulation circuit of a typical voice radio transmitter or transceiver unit. The amplitude shaping circuit includes a high-impedance sampling circuit which senses the steady state bias voltage at the signal input terminal during periods when no data are being transmitted. Upon receipt of a transmit-enable signal, the most recently sensed bias voltage is stored and positive and negative offset voltages are generated with respect to the stored voltage. One of the offset voltages is adjusted as a precisely determined voltage with respect to the stored voltage. The other of the offset voltages is generated by inverting the first, adjusted voltage, such that the two offset voltages are offset by equal values in opposite directions. An analog switch is adapted to receive a sequence of digital signals and to apply the positive and negative offset voltages to the signal input terminal in a sequence corresponding to the binary signal sequence of the received data signals.

Loading the Abstract Image...

First Claim