M491B

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 performedwith a 8192 step D/A converter, using the principle of voltage synthesis. The M491B is designed for 7-segment LED displays. Direct memory selection is possibleonly from remotecontrolwhile 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 M491B circuit also includes a PCM remote control receiver operating in conjunction with the transmitter M708. The highly reliable transmission code ensures error-free signal detection even in presence of high noise conditions. Search of the station is possible in automatic or manual modes. The circuit can operate with a Digital or LinearAFT control. The Digital AFTmode is necessary for automatic search and requires an external circuit (TDA4433 or equivalent, e.g. dual comparator plus TV station detector) to convert the AFC-S-curve into an Up/Down command.Fine tuning (detuning) is also possible with different modes of operation.Thecircuit is assembledin 40-pindual in-line plastic package.