Working principle analysis of the unit
1
、
PAL/SECAM signal flow
PAL/SECAM signal from antenna is inputted into TUNER
FQD1116
which is
an analog-digital-integrative model, the analog RF signal is demodulated by the
TUNER, then
CVBS
signal and
SIF(sound intermediate frequency)
signal are
outputted.
TUNER
FQD1116
is controlled by main chip
MSD209
（
with
embedded
CPU)
through
I2C
bus.
TV CVBS
signal is inputted into main chip
MSD209
directly to
be processed
by modules “
VIDEO DECODER
、
DEINTERLACE
and
SCALER
”, then
LVDS
signal is outputted to drive LCD panel.
SIF
audio signal is inputted into main chip
MSD209
directly and processed
by modules of demodulation, pre-amplification, acoustic effect processing and
volume control, then the audio signal are inputted into left and right sound tracks
of earphone amplifier
BH3547F
to be amplified and then are divided to two
signals, one is outputted to earphone jack, the other is inputted into
class D audio
power
amplifier
R2A15112
to be amplified and then be outputted to speakers.
2
、
DVB-T
signal flow
DVB-T
signal from antenna is inputted into TUNER
FQD1116
to be tuned,
RF
amplified,
IF
amplified and
SAW FILTER
inside, then
IF
signal is outputted to
demodulating chip
CE6353
to be demodulated and then be inputted into main
chip
MSD209
with format of standard serial or parallel
TS
stream for de
multiplexing
and decoding.
Video route: de
multiplexed
video signal is decoded by main chip
MSD209
and then digital video signal is outputted; in the end
LVDS
signal is outputted to
drive
LCD
panel after a series of digital processes and
OSD
addition within main
chip
MSD209
.
Audio route: de
multiplexed
audio signal is decoded into
Dolby AC-3
signal or
MPEG
multi-sound-track digital audio signal by inner decoder of main
chip
MSD209
, then one is outputted through
SPDIF
directly; after the process of
“sub-transform and
DAC
”, the other is outputted as analog audio signal, the analog
audio signal is inputted into the rear part of main chip
MSD209
for acoustic effect
processing and volume control, then inputted into left and right sound tracks of
earphone amplifier
BH3547F
respectively to be amplified, now the audio signal is
divided into two, one is outputted to earphone jack directly, the other is inputted into
class D
audio power amplifier
R2A15112
to be amplified and then outputted to speakers.
3
、
AV
signal flow
After processed by impedance matching,
AV
video signal is inputted into
main chip
MSD209
directly and processed by modules of “
VIDEO DECODER
、
DEINTERLACE
and
SCALER
”, then
LVDS
signal is outputted to drive
LCD
panel.
AV
audio signal is processed by circuits of “voltage divided, impedance
matching and
AC
coupling”, then inputted into main chip
MSD209
directly
for acoustic
effect processing and volume control, then inputted into left and right sound tracks of
earphone amplifier
BH3547F
respectively to be
