Abstract: A digital SSB modulator in which an analog signal such as a vocal signal is temporarily converted to a digital signal, which is then subjected to SSB modulation using digital phase shifters and digital orthogonal amplitude modulators, and the resulting signal is converted back to an analog modulated signal. A digital filter may be provided after each digital phase shifter for eliminating direct-current signal components. Another digital filter may be provided after each digital orthogonal amplitude modulator for eliminating carrier signal components.

Abstract: A binary signal modulator includes a sampling circuit for sampling a binary signal at a predetermined sampling frequency, a modulating circuit responsive to the sampled binary signal for generating a modulating signal, the rising and decaying timings of which are respectively determined by the start and end times of the binary signal and the rising and decaying characteristics of which are respectively defined as predetermined functions, and a circuit responsive to the modulating signal for generating a modulated signal.

Abstract: A frequency converting apparatus including a sample circuit and a bandpass filter wherein an input analog signal is sampled at predetermined periods only for predetermined time intervals to produce or increase the harmonic components of the original analog signal, a desired frequency component is extracted through the bandpass filter from the harmonic components to thereby convert the original signal having a particular frequency band to a signal having a higher-frequency band.