LC78622E Datasheet | SANYO

Overview The LC78622E is a CMOS LSI that implements the signal processing and servo control required by pact disc players. At the same time as providing an EFM PLL circuit, a 1-bit D/A converter, and an analog low-pass filter the LC78622E realizes an optimal cost-performance tradeoff for low-end players by strictly limiting functionality to basic signal-processing and servo system functionality. The LC78622E signal-processing system provides demodulation of the EFM signal from the pickup, de-interleaving, error detection and correction, and digital filters that can prove useful in reducing the cost of end products. The LC78622E servo control system processes servo mands sent from the control microprocessor. - - - - - - - - - - - Functions - Input signal processing: The LC78622E takes an HF signal as input, digitizes (slices) that signal at a precise level, converts that signal to an EFM signal, and generates a PLL clock with an average frequency of 4.3218 MHz by paring the phases of that signal and an internal VCO. - Precise reference clock and necessary internal timing generation using an external 16.9344 MHz crystal oscillator - Disk motor speed control using a frame phase difference signal generated from the playback clock and the reference clock - Frame synchronization signal detection, protection and interpolation to assure stable data readout - EFM signal demodulation and conversion to 8-bit symbol data - Subcode data separation from the EFM demodulated signal and output of that data to an external microprocessor - Subcode Q signal output to a microprocessor over the serial I/O interface after performing a CRC error check (LSB first) - Demodulated EFM signal buffering in internal RAM to handle up to ±4 frames of disk rotational jitter - Demodulated EFM signal reordering in the prescribed order for data unscrambling and de-interleaving - Error detection, correction, and flag processing (error correction scheme: dual C1 plus dual C2 correction) - The...