资 源 简 介
MM74HC943 300 Baud ModemGeneral DescripTIonThe MM74HC943 is a full duplex low speed modem. It providesa 300 baud bidirecTIonal serial interface for data communicaTIonover telephone lines and other narrow bandwidthchannels. It is Bell 103 compaTIble.The MM74HC943 utilizes advanced silicon-gate CMOStechnology. Switched capacitor techniques are used to peformanalog signal processing.MODULATOR SECTIONThe modulator contains a frequency synthesizer and a sinewave synthesizer. It produces a phase coherent frequencyshift keyed (FSK) output.LINE DRIVER AND HYBRID SECTIONThe line driver and hybrid are designed to facilitate connectionto a 600X phone line. They can perform two to four wireconversion and drive the line at a maximum of b9 dBm.DEMODULATOR SECTIONThe demodulator incorporates anti-aliasing filters, a receivefilter, limiter, discriminator, and carrier detect circuit. Thenine-pole receive filter provides 60 dB of transmitted tonerejection. The discriminator is fully balanced for stableoperation.
