Toshiba 21E88, Service Manual

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SERVICE MANUAL
5. TDA9808T
SINGLE STANDARD VIF-PLL WITH QSS-IF AND FM-PLL DEMODULATOR
1). Features
·5V supply voltage (9V supply voltage for
TDA9808T (DIP20) only)
·Applicable for IFs (lntermediate Frequencies) of
38.9MHz, 45.75MHz and 58.75 MHz
·Gain controlled wide band Video IF (VIF)-
amplifier (AC-coupled)
·True synchronous demodulation with active carrier
regeneration (very linear demodulation, good
intermodulation figures, reduced harmonics,
excellent pulse response)
·Robustness for over-modulation better than 105%
due to Phase Locked Loop (PLL)-bandwidth control
at negative modulated standards
·VIF Automatic Gain Control (AGC) detector for
gain control, operating as peak sync detector
·Tuner AGC with adjustable TakeOver Point (TOP)
·Automatic Frequency Control (AFC) detector
without extra reference circuit
·AC-coupled limiter amplifier for sound intercarrier
signal
·Alignment-free FM-PLL demodulator with high
linearity
·Sound IF (SIF) input for single reference Quasi
Split
Sound (QSS) mode (PLL controlled); SIF AGC
detector for gain controlled SIF amplifier, single
reference QSS mixer for high performance
·Electrostatic Discharge (ESD) protection for all
pins.
2). General Description
The TDA9808T is an integrated circuit for
single standard (negative modulated) vision
IF signal processing and FM demodulation,
with single reference QSS-IF in TV and VTR
sets.
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