Daewoo DTU-29M5ME, Руководство по обслуживанию, Страница: 64 / 77

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IC DESCRIPTION
The tuner receives a RF signal and converts it to IF. Via appropriate SAW filters the SIF signal
is delivered to the QSS stage of the video processor and if channels according to standard L/L’
are received also to the AM demodulator. The Quasi Split Sound demodulation generates the
SSIF or intercarrier signal. By the SSIF switch it is possible to choose between the internally
derivedintercarrier and an external second SIF(2NDSIFEXT), e.g. an intercarrier coming from a
PIP frontend. In other applications a 10.7MHz radio IF or satellite FM may be connected to this
input. The selected SSIF passes some anti alias filtering, is amplified in an AGC amplifier (SSIF
AGC) and is then converted from analogue to digital (SSIF ADC).
The audio signal out of the AM demodulator is connected to the analogue crossbar at the video
processor. All other inputs to this multiplexer/audio switch come from external, either from a PIP
frontend or SCART/CINCH(AUDINx) or the DAC output signals from the digital controller. The
audio AD converters are digitising the audio signals foreseen for further digital processing. One
stereo output (AUDOUTS) is available for connections to SCART/CINCH sockets.
The sound part on the digital controller consists of the demodulator/decoder(DEMDEC), a
digital input crossbar, the digital audio processing for the loudspeaker and DAC channels, the
I2S processing and interfacing, a digital output crossbar as well as the DA conversion.
An auxiliary audio control (volume control, AUX audio contr.) is available on the video
processor.
Here it is applied to the headphone channel.
The part of the concept located in the digital controller will be described in the next chapters.