Philips CD2 - Second generation CD system - 1984

Philips CD2 is the first all-integrated system for CD players. CD2 means improved performance for the listener, and simpler more flexible designs for the manufacturer. This additional flexibility stems from a single-chip decoder concept which can be expanded for full-performance designs by adding a digital oversampling filter IC.

An analog filter IC can be used to make either a low-order analog filter for a full-performance player or a high-order filter for a low-cost player. Two bipolar ICs provide all the control servo functions for a singlebeam swing arm pick-up. A full-performance player is shown in Fig.1. This player which requires no factory adjustment comprises:

CD mechanism

Philips CDM2: a smaller version of our swing arm mechanism Philips CDM1 in a tough plastic surround. Height of the CDM2 is 30 mm. Operating temperature range is —30 °C to +75 °C. These features and a very short arm with low moment of inertia make CDM2 suitable for use in portable and car CD players.

Servo electronicsm

Philips TDA5708: bipolar photodiode signal processor

• photodiode signal preamplifiers with separate r.f. and d.c. a.g.c.s for optimum generation of the r.f. data signal and the focusing/tracking error signals
• tracking error signa! amplifier
• focusing 'error signal processor with focus normalising and start-up circuit
• data equalizer
• r.f. level and track-loss detectors
• regulated supply for the reading laser diode
• low current consumption: 15 mA (8 V — 14 V).

Philips TDA5709: bipolar radial error processor

• tracking error processor with automaticasymmetry control
• a.g.c. circuitry with automatic start-up and wobble generator
• tracking control for fast forward/reverse scan, search, repeat and pause functions
• low current consumption: 10 mA (8 V — 14 V).

Decoding electronics

The decoder comprises three ICs compared with the six ICs of our previous decoder. In addition, an IC is avajiable for constructing a variety of low-pass analog filters.

Philips SAA7220: NMOS digital filter with enhanced concealment of uncorrectable errors

• two identical phase-linear digital FIR filters with 120 filter coefficients
• four times oversampling
• linear interpolation of up to 8 consecutive erroneous samples
• I2S data I/O for compatibility with future sound processors
• integrated digital audio output according to the PhilipsSony proposal
• soft mute of audio when starting, stopping or pausing
• 12 dB attenuated audio facility when scanning.

Philips TDA 1541: bipolar dual 16-bit DAC

• two separate DACS on one chip (no multiplexing, so no delay between the stereo channels)
• operates at bit rates up to 6 Mblts/s for use with four times oversampled data in the CD system
• programmable for offset binary or two's complement signals
• I2S input format
• 1 ps (typ.) settling time to ± 1 LSB,

Philips TDA1542: bipolar dual analog output IC

• an be used to make a iow-order analog filter for a fullperformance player with digital filtering, or a high-order filter for a low-cost player using a single-chip (SAA7210) decoder
• two identical circuits for stereo applications
• incorporates de-emphasis switch and silent switch-on/off circuitry
• headphone output.

Philips SAA7210: NMOS single-chip decoder

• comprises all decoding functions:

  • demodulator with adaptive data slicer
  • fully-integrated demodulator PLL
  • subcoding data processor
  • error corrector with adaptive error-correction strategy
  • basic interpolation and sample-and-hold circuit
• improved error correction — of up to a 15-frame burst error
• large (64-frame) FIFO storage for portable and car player applications
• I2S (inter-IC signal) data output.

Source: Philips Electronics components & applications. VOL. 6 NO. 4. August 1984