TDA9821 데이터 시트보기 (PDF) - Philips Electronics
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TDA9821 Datasheet PDF : 16 Pages
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Philips Semiconductors
Dual channel TV FM intercarrier
sound demodulator
Product specification
TDA9821
PINNING
SYMBOL PIN
DESCRIPTION
IN1(B/G)
n.c.
1 intercarrier input 1 at 5.5 MHz
2 not connected
n.c.
3 not connected
n.c.
4 not connected
n.c.
5 not connected
n.c.
6 not connected
VAF2
VAF1
C1
C2
VCOref
CSTAB
GND
7 audio output voltage 2
8 audio output voltage 1
9 decoupling capacitor 1
10 decoupling capacitor 2
11 VCO reference
12 supply voltage stabilization
13 ground
VP
IN2(B/G)
n.c.
14 supply voltage
15 intercarrier input 2
16 not connected
handbook, halfpage
IN1(B/G) 1
n.c. 2
n.c. 3
n.c. 4
n.c. 5
n.c. 6
VAF2 7
VAF1 8
16 n.c.
15 IN2(B/G)
14 VP
13 GND
TDA9821
12 CSTAB
11 VCOref
10 C2
9 C1
MHA531
Fig.2 Pin configuration.
FUNCTIONAL DESCRIPTION
The complete circuit consists of two separate channels,
each consisting of a limiter-amplifier, FM demodulator and
AF amplifier. Circuit operation is also described in Fig.1.
FM demodulators
The intercarrier signal is fed through external ceramic
band-pass filters which are tuned to the sound carrier
frequencies.
Each limiter-amplifier is AC-coupled into a
FM demodulator. The integrated FM demodulator PLLs
are alignment-free. The FM demodulator outputs are
amplified to 500 mV (RMS value). High amplification and
DC error signals of the PLLs, which are superimposed on
the FM demodulator outputs, require DC decoupling at
pins 9 and 10 of the AF amplifier inputs.
Stereo channel separation adjustment (optional)
Optimal stereo channel separation is achieved by
adjusting VAF1 (pin 8) and VAF2 (pin 7) as follows:
1. VAF1 by a resistor in series with the DC decoupling
capacitor at pin 9
2. VAF2 by a variable resistor in series with the
DC decoupling capacitor on pin 10 to the same
voltage as VAF1.
Normally stereo channel separation is adjusted in the
stereo decoder for the B/G standard.
1996 Nov 20
4
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