GENERAL DESCRIPTION The SAA7705H performs all the signal functions in front of the power amplifiers and behind the AM and FM multiplex demodulation of a car radio or the tape input. These functions are: • Interference absorption • Stereo decoding • RDS decoding • FM and AM weak signal processing (soft mute, sliding stereo, etc.) • Dolby-B tape noise reduction • Audio controls (volume, balance, fader and tone). FEATURES Hardware • Three 3rd-order Switched Capacitor Analog-to-Digital converters (SCADs) • Digital-to-Analog Converters (DACs) with four times oversampling and noise shaping • Digital stereo decoder for the FM multiplex signal • Improved digital Interference Absorption Circuit (IAC) for FM • Radio Data System (RDS) processing with an optional 16-bit buffer via a separate channel (two tuners possible) • Auxiliary high Common-Mode Rejection Ratio (CMRR) analog CD input (CD-walkman, speech, economic CD-changer, etc.) • I2C-bus controlled • Four channel 5-band I2C-bus controlled parametric equalizer • Two separate full I2S-bus and LSB-justified formats high performance input interfaces • Audio output short-circuit protected • Separate AM left and right inputs • Phase-Locked Loop (PLL) to generate the high frequency DSP clock from a common fundamental oscillator crystal • Analog single-ended tape inputs • I2S-bus subwoofer output (mono or stereo) • Expandable with additional DSPs for sophisticated features through an I2S-bus gateway • Operating ambient temperature from −40 to +85 °C. Software • Improved FM weak signal processing • Integrated 19 kHz MPX filter and de-emphasis • Electronic adjustments: FM/AM level, FM channel separation and Dolby level • Baseband audio processing (treble, bass, balance, fader and volume) • Dynamic loudness or bass boost • Audio level meter • Tape equalisation (tape analog playback) • Music Search System (MSS) detection for tape • Dolby-B tape noise reduction • Adjustable dynamics compressor • CD de-emphasis processing • Improved AM reception • Soft audio mute • AM IAC • Pause detection for RDS updates • Signal level, noise and multipath detection for AM/FM signal quality information. APPLICATIONS • Car radio systems
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