PURPOSE: To provide a PWM(pulse width modulation) signal MODEM circuit which can improve its resolution with no limitation caused by such decision factors in terms of a circuit of resolution as the swing width of an analog signal, the bit number of a timer counter, etc., when the PWM signal is demodulated into an analog signal.
CONSTITUTION: An input signal is amplified by an input amplifier 1 and then converted into a digital signal by an A/D converter of an MPU 3 while undergoing the switching of its gain through an analog switch 2. At the same time, the input signal is modulated into a PWM signal by a timer unit of the MPU 3 and converted into an analog signal through the buffers 4 and 5 together with the switching of the gain of an output amplifier 6. Then an output signal is obtained through an LPF 8.
| JPS57203328 | DIGITAL-TO-ANALOG CONVERTER |
| JPS5961311 | DIGITAL SIGNAL TRAIN GENERATOR |
| JP2940759 | D/A CONVERTER |
TAKAMIYA MASASHI
NENE YOSHITO
