Patent attributes
Provided is a digital modulation circuit constructed with only a digital circuit. The digital modulation circuit includes: a clock generator which generates a reference clock pulse having a predetermined period; an up/down counter which generates a count value having predetermined bits by up-counting or down-counting the reference clock pulse and outputs a bit in the count value as a transmission signal; a controller which determines a counting start/end time point of the up/down counter and determine which one of the up-counting operation and the down-counting operation of the up/down counter is to be performed, according to a value of digital transmission data that is to be transmitted; and a band-pass filter which converts a waveform of the transmission signal output from the up/down counter into a sine waveform.
