Low Bit Rate Voiceband Encoders/Decoders HC-55536 Semiconductor March 1993 Features • All Digital D E D EN Continuously Variable Slope M M S O N Delta-Demodulator (CVSD) C G I E S E TR D O Description N EW N FOR • Requires Few External Parts • Low Power Drain: 1.5mW from Single 3V to 6V Supply • Time Constants Determined by Clock Frequency; No Calibration or Drift Problems; Automatic Offset Adjustment • Filter Reset by Digital Control • Automatic Overload Recovery • Automatic “Quiet” Pattern Generation The HC-55536 is a CMOS integrated circuit used to convert serial NRZ digital data to an analog (voice) signal. Conversion is by delta demodulation, using the Continuously Variable Slope (CVSD) method of demodulation. While signals are compatible with other CVSD circuits, the internal design is unique. The analog loop filters have been replaced by digital filters which use very low power and require no external timing components. This digital approach allows inclusion of many desirable features, which otherwise would be difficult to implement. The device is usable from 9Kbits/s to above 64kbits/s, and may be easily configured with the HC-55564 CVSD for a complete transmit/receive voice channel. Applications • Voice Decoder for Digital Systems and Speech Syntheses Ordering Information PART NUMBER • Voicemail TEMP. RANGE (oC) PACKAGE PKG. NO. • Audio Manipulations; Delay Lines, Echo Generation/ Suppression, Special Effects, etc. HC1-55536-5 0 to 75 14 Ld CERDIP HC1-55536-9 -40 to 85 14 Ld CERDIP • Pagers/Satellites HC3-55536-5 0 to 75 14 Ld PDIP HC3-55536-9 -40 to 85 14 Ld PDIP Functional Diagram Pinout HC-55536 (PDIP, CERDIP) TOP VIEW VDD 1 14 NC NC 2 13 FZ AOUT 3 (13) (12) FORCE ZERO DIGITAL IN 3 BIT SHIFT REGISTER 12 DIGITAL INPUT NC 4 11 NC NC 5 10 NC NC 6 9 CLOCK NC 7 8 DIGITAL GND 1 SYLLABIC DIGITAL FILTER 4.0msec 10 10 BIT DAC ZO AOUT (3) CLOCK (9) CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper IC Handling Procedures. Copyright © Harris Corporation 1997 4-252 VDD (1) 6 DIGITAL MODULATOR +1 6 SIGNAL ESTIMATE DIGITAL FILTER 1.0msec DIGITAL GND (8) File Number 2888.1