DESCRIPTION
The M491B is a monolithic N-MOS LSI circuit including a Floating-gate Non-Volatile Memory for storage of up to 16 stations. Tuning of the station is performed with a 8192 step D/A converter, using the principle of voltage synthesis. It is designed for 7-segment LED displays. Direct memory selection is possible only from remote control while Up/Down memory scanning is possible on the set and also from remote control. An option input for 8 or 16 stations is available. The circuit also includes a PCM remote control receiver operating in conjunction with the transmitter M708.

■ 16-STATION MEMORY - 7-SEGMENT LED DISPLAY
■ VOLTAGE SYNTHESIZER : 13 BITS
■ 4-BAND PRESET CAPABILITY
■ NON-VOLATILE MEMORY : 304 BITS
   - 16 WORDS OF 19 BITS FOR TUNING VOLTAGE (13 bits) - BAND (2 bits) - FINE DETUNING (4 bits)
   - 104 MODIFY CYCLES PER WORD
   - MIN 10 YEARS DATA RETENTION
■ PCM REMOTE CONTROL RECEIVER : DECODES SIGNAL TRANSMITTED BY M708
■ VOLUME D/A : 6-BIT RESOLUTION / 8kHz
■ MEMORY SKIP FUNCTION
■ AUTOMATIC SEARCH WITH DIGITAL AFT CONTROL
■ FINE DETUNING D/A ACTING ON AFT DISCRIMINATOR (16 steps) WITH SEPARATE STORAGE FOR EACH MEMORY POSITION.
   ALTERNATIVELY IT CAN BE USED TO CONTROL BRIGHTNESS OR COLOUR SATURATION
■ MANUAL SEARCH WITH DIGITAL AFT CONTROL
■ MANUAL SEARCH WITH LINEAR AFT
■ SWEEP SEARCH DISPLAY OUTPUT
■ SUPPLY VOLTAGES : VDD = + 5V, VPP = + 25V FOR THE MEMORY
■ CLOCK OSCILLATOR : 445 TO 510kHz
■ INTEGRATED DIGITAL POWER ON RESET
   (no external initialization circuitry required)