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CIRCUIT DESCRIPTION
Front Equalizer IS05
The Front Audio can be frequency adjusted to suite the particular room environment. The individual fre-
quency notches are adjusted via the customers menu. The following frequency notches are adjusted by this
IC. 60HZ,
250HZ, 1KHz, 3KHz, and 10KHz. Communication from the Microprocessor via pins (59 SDA2 and 60
SCL2) then through the connector PSU1 pins (2 and 1) which arrives at the IS05 at pins (17 and 16)
respectively.
Center Equalizer IS10
The Center Audio can be frequency adjusted to suite the particular room environment. The individual
frequency notches are adjusted via the customers menu. The following frequency notches are adjusted by
this IC. 60HZ, 250HZ, 1KHz, 3KHz, and 10KHz. Communication from the Microprocessor via pins (59
SDA2 and 60 SCL2) then through the connector PSU1 pins (2 and 1) which arrives at the IS05 at pins (17
and 16) respectively.
Rear Audio Control IS11
The Rear Audio Control IC has the ability to adjust balance, treble, bass, volume and mute. This mute is the
one that is activated when the mute button is pressed on the remote control. Communication from the
Microprocessor via pins (57 SDA3 and 58 SCL3) then through the connector PSU1 pins (4 and 3) which
arrives at the IS11 at pins (4 and 5) respectively.
Audio DSP (Digital Signal Processor) DSP Unit HC4051
The Digital Signal Processor is responsible for decoding Dolby Pro-Logic, AC-3 audio and selecting the
output of the audio determined by the customers menu. Such as Off, Matrix, Hall, etc Control for the
DSP is routed from the Microprocessor pins (15 DSPSS DSP Surround Sound Mode, 16 DSPSCK DSP
Clock, 17 DSPI DSP Mode 1, 18 DSPERR Mute DSP Error Mute, and 19 DSPRST DSP Re-set). Then
to the Level Shift, IC I014 pins (5, 6, 8, 7, and 9) respectively. These signals are then routed to the PSU2
connector pins (5, 2, 3, 6, and 1) respectively to the DSP module via the PMU1 connector pins (9, 12, 11,
8 and 13) respectively.
OSD Genaration
The Microprocessor is responsible for generating On Screen Display (OSD) related to the Main Menu,
Volume Control, Channel Number, Closed Caption Display, Clock, etc It also generates the OSD for the
Service Menu. However there are actually two different sources for generating OSD, the Microprocessor
and the Digital Convergence Unit, (DCU).
MICROPROCESSOR AS THE SOURCE FOR OSD
The Microprocessor receives information related to timing for H. Blanking and V. Blanking. These arrive at
pins (49 and 55) respectively. The Microprocessor determines the position for each display using these
signals as a timing pulse. When necessary, the Microprocessor generates 1uSec pulses from pins (37 Red,
38 Green and 39 Blue) that are routed through the PSZ1 connector pins (14 Red, 16 Green and 18 Blue).
These are then routed through (QX07 Red, QX08 Green and QX09 Blue) and sent to the Rainforest IC
IX01 pins (39 Red, 38 Green and 37 Blue) as OSD signals. When the OSD signals are high, they turn on
the output of the Red or Green or Blue chroma amps inside the Rainforest IC and output a pulse to the
CRTs to generate that particular character in the particular color.
