Philips tea7650h DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

TEA7650H

Video signal processor for CD-video/laser vision

Preliminary speciﬁcation File under Integrated Circuits, IC02

September 1990

Philips Semiconductors Preliminary speciﬁcation

Video signal processor for CD-video/laser vision TEA7650H

FEATURES

• Modulation Transfer Function correction (MTF) at signal input for both standards

• HF drop out detector

• Data slicer, data output for program information

(IEC standards)

• Separation of signals for Electronic Time Base Correction (ETBC)

• Noise reduction with chrominance trap, noise level adjust point

GENERAL DESCRIPTION

Bipolar IC for video signal processing used in CD-Video/LaserVision players. Standard PAL respectively NTSC output signal (CVBS). MTF amplifier. FM-demodulator followed by de-emphasis stage. PAL/NTSC switch for switching the MTF and de-emphasis. Drop out detector with drop out switch, also externally switchable.

+5 volt supply, only 325 mW total power dissipation.

• Dynamic picture insertion and 6 dB video attenuation of

main picture

• Bandgap reference voltage output, suitable for CCD delay line

QUICK REFERENCE DATA

SYMBOL PARAMETER MIN. TYP. MAX. UNIT

i (p-p)

o (p-p)

i (p-p)

supply voltage (pins 12, 30, 47) − 5 − V total supply current −−65 mA FM input signal at pin 7 (peak-to-peak value) 50 − 300 mV CVBS output signal for CCDs (peak sync − peak white, pin 29) − 850 − mV black level voltage (pin 29) − 1.85 − V delayed CVBS input signal for drop out path at pin 27

(peak-to-peak value) − 700 − mV

i (p-p)

delayed CVBS input signal at pin 31 from ETBC path (peak-to-peak value) − 600 − mV

o (p-p)

main CVBS output signal at pin 42 (peak-to-peak value) − 1 − V black level voltage (pin 42) − 2.2 − V chrominance output signals at pins 44, 48 (peak-to-peak value)

PAL (burst) − 760 − mV NTSC (burst) − 725 − mV

ref

reference output voltage (pin 41) − 1.6 − V

ORDERING AND PACKAGE INFORMATION

EXTENDED TYPE NUMBER

TEA7650H 48 QFP48 plastic SOT196A

Note

1. SOT196-1; 1996 November 25.

September 1990 2

PACKAGE

PINS PIN POSITION MATERIAL CODE

(1)

Philips Semiconductors Preliminary speciﬁcation

Video signal processor for CD-video/laser vision TEA7650H

September 1990 3

Fig.1 Block and test circuit; (continued in Fig.2)

Philips Semiconductors Preliminary speciﬁcation

Video signal processor for CD-video/laser vision TEA7650H

September 1990 4

Fig.2 Block and test circuit; (continued from Fig.1).

Philips Semiconductors Preliminary speciﬁcation

Video signal processor for CD-video/laser vision TEA7650H

PINNING

SYMBOL PIN DESCRIPTION

CRSC1 1 3.67 MHz resonant circuit 1 CS1 2 line synchronization output pulse 1 (composite sync) DOCO 3 drop out control, input/output for external control VS 4 ﬁeld sync output C

MTF

FM-IN 7 FM input signal from preampliﬁer FREF1 8 PAL resonant circuit for the MTF FREF2 9 NTSC resonant circuit for the MTF MTFO 10 MTF output signal (corrected FM signal) AMPIN 11 input for 8 dB ampliﬁer (FM signal) V

AMPO 13 output of 8 dB ampliﬁer (FM signal) LIMIN1 14 limiter ampliﬁer input (FM signal to demodulator) C

LIM

DEM

DRQ 17 data request input for data at pin 25 DEMO 18 FM demodulator output (CVBS negative) GND1 19 ground (0 V) for V FBO1 20 feedback output at PAL and NTSC (de-emphasis) FBO2 21 feedback output, additional at NTSC (de-emphasis) C

CVBS

DEEMI 23 de-emphasis input for CVBS from demodulator C

AGC1

DATA 25 data output of information code C

AGC2

PRLIN 27 input signal of preceding line from CCD delay GND3 28 ground (0 V) for V DOSW 29 drop out switch buffer output (to CCD delay and ETBC) V

VIDIN 31 CVBS input signal from ETBC C

AGC3

VIBUF 33 video signal buffer output to chroma trap circuitry FTRAP 34 switching output for chroma trap at NTSC LIMI2 35 limiter ampliﬁer input for noise reduction NRADJ 36 noise level adjust point (resistor to ground) MODE 37 standard select input PAL/NTSC (PAL = LOW) INSEN 38 insertion enable input VDATT 39 6 dB CVBS attenuation (active HIGH) EXVID 40 external CVBS input for insertion

5 charging capacitor for burst rectiﬁer 6 charging capacitor for MTF control voltage

12 +5 V supply (referred to pins 6 to 15 and 18)

15 capacitor for slicing level control of limiter 16 capacitor for clamping level of FM demodulator

22 capacitor for clamping of CVBS ampliﬁer

24 capacitor for AGC of CVBS ampliﬁer

26 capacitor for AGC of drop out ampliﬁer

30 +5 V supply (referred to pins 5, 17, 20 to 36, 38 to 42)

32 capacitor for AGC of CVBS follower ampliﬁer

September 1990 5

Philips Semiconductors Preliminary speciﬁcation

Video signal processor for CD-video/laser vision TEA7650H

SYMBOL PIN DESCRIPTION

ref

CVBS 42 main CVBS output signal GND2 43 ground (0 V) for V CHR2 44 chrominance output signal 2 CRSC2 45 3.67 MHz resonant circuit 2 CS2 46 line synchronization pulse 2 (composite sync) V

CHR1 48 chrominance output signal 1

PIN CONFIGURATION

41 reference voltage output (1.6 V)

47 +5 V supply (referred to pins 1 to 4, 16, 37, 43 to 48)

September 1990 6

Fig.3 Pin configuration.

Philips Semiconductors Preliminary speciﬁcation

Video signal processor for CD-video/laser vision TEA7650H

FUNCTIONAL DESCRIPTION

Figures 1, 2 show the block diagram of the Video Signal Processor (VSP) including the peripheral circuitry for the video signal processing. The pulse-width modulated FM signal from the preamplifier is fed, via a DC blocking capacitor, into the IC (pin 7) at the input to the Modulation Transfer Function (MTF) circuit which corrects for the characteristic of the optical reading system.

MTF correction

Due to the finite diameter of the laser beam spot and the tangential velocity of the track of pits on the disk, the MTF of the optical system acts like a radius-dependent low-pass filter for the FM input signal. Although the video signal can be recovered without correction, the ratio of the amplitudes of the chrominance and luminance signals would not then be the same at the most inner and the most outer part of the disk. This influence of the disk radius is automatically corrected by the Video Signal Processor. The principle of correction is to use the deviation of the demodulated burst signal to generate an error voltage in order to control the frequency selective MTF circuit. The burst measurement operates as follows: A burst-key generator is triggered by the line synchronization pulse (CS1) to generate a burst-key pulse which activates the burst gate and rectifier stage. The signal at the rectifier output (pin 6) is used to control the amplification of the MTF circuit.

The carrier frequency in the PAL standard is different to that in the NTSC standard, therefore two separate resonant circuits are required on pins 8 and 9. They are selected by the PAL/NTSC system selector (pin 37).

De-emphasis

The de-emphasis circuit consists of an internal inverting amplifier and an external RC feedback network. Since the pre-emphasis on the disk in the PAL standard is different from that in the NTSC standard, the time constants are switchable. When PAL is selected, the first arm of the feedback network is active, otherwise both operate in parallel. The de-emphasized video signal is fed into an AGC stage (pin 20) where it is clamped on its black level and amplitude-controlled to a constant level. The signal is then fed into the data slicer and the drop out switch.

Data slicer

Coded signals on the video disk are extracted by the data slicer (output pin 25) when the Data Request input is activated (pin 17).

Drop out compensation

The drop out detector (DOD) in the IC is triggered by every positive or negative transition of the FM signal. A drop out is detected when the half-cycle period is outside the limits. Protection against a drop out is achieved by use of a video signal delayed by one line. The signal at the output of the drop out switch is fed out of the IC via a buffer (pin 29) and then through a delaying device (CCD) before being fed back into the IC (pin 27). The delayed video signal appears at the input of an AGC circuit to compensate for gain tolerances of the delay line and avoids the need for an external adjustment. When a drop out is detected, the drop out detector activates the video switch so that the lost information of the line is substituted by the information of the preceding line.

The MTF-corrected FM signal at pin 10 is amplified (+8 dB) and fed, via the external filter which removes the audio frequency components from the signal, into the demodulator at pin 14.

Demodulation

The FM signal is first fed into a limiter circuit (pin 14) with automatic slicing level control to suppress the main carrier in the demodulated signal. The demodulator has two outputs. The first (internal) clamps the demodulated video signal on peak-sync by controlling the transconductance of the demodulator. The FM signal can now be demodulated during disk start-up, thereby facilitating fast run-in. The second output signal from the demodulator (pin 18) is passed through an external 5 MHz low-pass filter to extract the CVBS signal. The CVBS signal is then fed into the de-emphasis network to compensate for the pre-emphasis of the video signal recorded on the disk.

September 1990 7

The drop out pulse is also present at pin 3 and can be used for different purposes. This pin can also act as an input to control the drop out switch by an external signal for test purposes.

Time error compensation

In a videodisc player timing errors are caused by deviations of the rotational speed of the motor, imperfections in the disk and unavoidable tolerances in the centering of the disk on the turntable. Track eccentricity is the main cause of timing errors.

To minimize timing errors, it is necessary in the first place to keep the rotational speed of the disk as constant as possible. Referring back to the output of the switch in Fig.1-2, the video signal is also fed into a sync separator and a chrominance separator with its external resonant circuits tuned to the chrominance subcarrier

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