Toshiba 27WLT56B, Руководство по обслуживанию

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5
27” TFT TV Service Manual 05/09/2005
12.1.
TDA9886
12.1.1. General Description
The TDA9885 is an alignment-free single standard (without positive modulation) vision and sound IF signal
PLL.
12.1.2. Features
• 5 V supply voltage
•
Gain controlled wide-band Vision Intermediate Frequency (VIF) amplifier (AC-coupled)
•
Multistandard true synchronous demodulation with active carrier regeneration (very linear demodulation,
good intermodulation figures, reduced harmonics, excellent pulse response)
• Gated phase detector for L/L accent standard
•
Fully integrated VIF Voltage Controlled Oscillator (VCO), alignment-free; frequencies switchable for all
negative and positive modulated standards via I
2
C-bus
• Digital acquisition help, VIF frequencies of 33.4, 33.9, 38.0, 38.9, 45.75 and 58.75 MHz
•
4 MHz reference frequency input [signal from Phase-Locked Loop (PLL) tuning system] or operating as
crystal oscillator
•
VIF Automatic Gain Control (AGC) detector for gain control, operating as peak sync detector for negative
modulated signals and as a peak white detector for positive modulated signals
•
Precise fully digital Automatic Frequency Control (AFC) detector with 4-bit digital-to-analog converter; AFC
bits via I
2
C -bus readable
•
TakeOver Point (TOP) adjustable via I
2
C-bus or alternatively with potentiometer
•
Fully integrated sound carrier trap for 4.5, 5.5, 6.0 and 6.5 MHz, controlled by FM-PLL oscillator
•
Sound IF (SIF) input for single reference Quasi Split Sound (QSS) mode (PLL controlled)
•
SIF AGC for gain controlled SIF amplifier; single reference QSS mixer able to operate in high performance
single reference QSS mode and in intercarrier mode, switchable via I
2
C-bus
•
AM demodulator without extra reference circuit
•
Alignment-free selective FM-PLL demodulator with high linearity and low noise
• I
2
C-bus control for all functions
• I
2
C-bus transceiver with pin programmable Module Address (MAD).
12.1.3. Pinning
SYMBOL PIN DESCRIPTION
VIF1 1 VIF differential input 1
VIF2 2 VIF differential input 2
OP1 3 output 1 (open-collector)
FMPLL 4 FM-PLL for loop filter
DEEM 5 de-emphasis output for capacitor
AFD 6 AF decoupling input for capacitor
DGND 7 digital ground
AUD 8 audio output
TOP 9 tuner AGC TakeOver Point (TOP)
SDA 10 I
2
C-bus data input/output
SCL 11 I
2
C-bus clock input
SIOMA
12
sound intercarrier output and MAD select
n.c.
13
not connected
TAGC 14 tuner AGC output
REF 15 4 MHz crystal or reference input
VAGC 16 VIF-AGC for capacitor; note 1
CVBS 17 video output
AGND 18 analog ground
VPLL 19 VIF-PLL for loop filter
V
P
20 supply voltage (+5 V)
AFC 21 AFC output