Modulator for generating an amplitude-keyed radio-frequency signal

A modulator for generating an amplitude-keyed radio-frequency signal contains a counter started by the audio-frequency keying signal with each keying, which counter generates the signal edge of a linearly falling or rising ramp. This linear signal is used for addressing a read-only memory which outputs a control signal for a rounded non-linear edge characteristic. The control signal is applied to the digital input of a D/A converter with a resistance network, at the reference voltage input of which an unmodulated RF signal is present. After filtering and amplification, the analog output signal of the D/A converter forms the amplitude-keyed RF signal.