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