Modulator for generating an audio-frequency-modulated single side band signal with suppressed carrier

摘要

To generate this signal, an unmodulated RF signal is applied to the reference signal connection of a D/A converter with resistance network. At the zero crossing of the audio-frequency modulation signal, the phase of the RF signal is switched over by 180@. From the audio-frequency modulation signal, digital control values are derived for the D/A converter which, as a result, operates as controllable RF attenuator. At the output of the D/A converter, a DSB signal is available from which the required side band can be obtained by means of a filter.