Description

The HC-55564 is a half duplex modulator/demodulator CMOS intergrated circuit used to convert voice signals into serial NRZ digital data and to reconvert that data into voice. The conversion is by delta-modulation, using the Continuously Variable Slope (CVSD) method of modulation/demodulation.

Features

• All Digital

• Requires Few External Parts

• Low Power Drain: 1.5mW Typical From Single 4.5V To 6V Supply

• Time Constants Determined by Clock Frequency; No Calibration or Drift Problems: Automatic Offset Adjustment

• Half Duplex Operation Under Digital Control

• Filter Reset Under Digital Control

• Automatic Overload Recovery

• Automatic “Quiet” Pattern Generation

• AGC Control Signal Available

Applications

• Voice Transmission Over Data Channels (Modems)

• Voice/Data Multiplexing (Pair Gain)

• Voice Encryption/Scrambling

• Voicemail

• Audio Manipulations: Delay Lines, Time Compression, Echo Generation/Suppression, Special Effects, etc.

• Pagers/Satellites

• Data Acquisition Systems

• Voice I/O for Digital Systems and Speech Synthesis Requiring Small Size, Low Weight, and Ease of Reprogrammability

• Related Literature - AN607, Delta Modulation for Voice Transmission