Daewoo DDT-21H9ZDF(21"), Service Manual

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Service Manual CP-099/FS
5-7 Audio processing (cp-099)
5-7-1 Mono audio signal from IF IC-input section
In the case of 2 Carrier FM transmission, the controlling software read the transmission mode and the signal quality level
from the Stereo Detection Register. When the set is in “Auto detection” mode the controlling software automatically sets
the sound mode ( mono, Stereo, Dual 1, Dual 2 ) depending on the transmitted mode.
In “Auto detection” mode the controlling software evaluates the signal quality and automatically switches to the analogue
sound carrier 1, if the transmission quality is too poor. To avoid unwanted automatic switching the threshold levels
mono to stereo and stereo to mono are different.
In “forced mono “ mode ( Red OSD in status Display Window), the controlling software configures the MSP341xD to
demodulate the analogue (FM or AM) sound carrier 1, no matter the signal quality. The sound mode “ forced “ or “
Autodetect” is stored for each programme.
The output of 8
th
pin(TDA9886) is audio frequency, which delivers mono audio signal to TDA9859(volume control IC).
Refer to the section(5-2-8 ~ 5-2-14) of Service manual for the sound signal process.
5-7-2 Source select switching block
The TDA9859 selects and switches the input signals from three stereo or six mono sources to the outputs Two Mono
inputs for RF and Two Stereo inputs for SCART & DVD are available.
5-7-3 Effect controls
Linear stereo(STANDARD), STEREO with spatial effect 52%(MUSIC) and forced mono without pseudo-stereo
effect(MONO) are provided. A mute is provided.
5-7-4 Loudspeaker Channel
Volume control is divided into volume control common and volume control left/right. The common part
control the left and right channels simultaneously; the left/right part controls the volume of left and right
channels independently. Treble control & bass are provided.
5-7-5 Sound System Selection
Auto sound system detection is not available for the model DDT-14H9ZZF. After ATSS channel searching
finished, user selections of sound system from EDIT menu are needed.