PURPOSE: To improve mass production capacity, to simplify circuit constitution, and to lower manufacturing cost, by taking out digital data to be transmitted from a first circuit means as serial data, bit by bit, supplying it to a conversion means, converting it to a 180° phase modulated rectangular wave signal, and inputting the signal to a second circuit means.
CONSTITUTION: A shift register 14 responds to the rising timing of a clock pulse signal CK, and shifts the data of 9 bits in order, and changes it to bit- serial data, and inputs it to an Ex-OR gate 15 in order as data D0. And the data D0 is converted to and outputted as the 180° phase modulated rectangular wave signal by the Ex-OR gate 15. The higher harmonic signal component of a conversion output signal CS is eliminated by a low-pass filter 17, and a transmission signal TS comparatively similar to a sine wave and of pseudo sine wave shape can be obtained. Thus, since the conversion of prescribed data D to be transmitted to the 180° phase modulated rectangular wave signal is performed by one Ex-OR gate 15, the circuit constitution can be simplified and the profitability of miniaturization and making into an IC can be obtained.
KOIZUMI TADAO
MASUDO KAZUYUKI
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