Patent ID: 7965792

Claim:
A modulation-index adjustable ASK (amplitude shift keying) transmitter comprising: a bias current supply unit supplying one or more bias currents in response to a digital signal that is to be transmitted and one or more bias current control signals; and a modulation signal generator generating a modulation signal corresponding to the digital signal by modulating a carrier signal in response to the one or more bias currents, wherein each of the one or more bias current control signals includes a falling edge control signal for determining a falling edge transition time of the modulation signal and a rising edge control signal for determining a rising edge transition time of the modulation signal, and the bias current supply unit comprises one or more bias current supply circuits for generating the bias currents in response to the digital signal and the bias current control signals; and wherein the bias current supply circuit comprises: a reference bias supply circuit supplying a first reference bias voltage in response to the digital signal; a bias current control circuit generating a bias control voltage in response to the first reference bias voltage, the rising edge control signal, and the falling edge control signal; and a bias current output circuit generating the bias current in response to the bias control voltage.