Individual Ic Functional Description; Ic1201 System Control; Ic1101 Digital Audio I/F Receiver (Dir; Ic1301 Digital Audio Decoder (Dad - Sony STR-DE845 Training Manual

Chapter Title
Appendix: Individual IC Functional Description
This section gives a brief functional description of each major IC on the Digital board.

IC1201 System Control

IC1201 is the central control microprocessor for the receiver. Its main functions are Switching control for Digital
Input switch IC1005 (pins 107 and 108) and Analog signal switch's IC301, IC303 and IC1502 (pins 46, 47 and 48
for all three ICs), Reset for all ICs on the digital board, Serial control for the Digital Audio I/F receiver, Digital
Audio decoder, Codec, and Parallel control of Audio DSP. IC1201 also generates a user controlled System
Mute, which is activated by pressing the mute button on the front panel.

IC1101 Digital Audio I/F Receiver (DIR)

The DIR receives the Sony/Phillips digital interface protocol (S/P DIF) signal, which contains the necessary
Overhead and Surround Sound protocol Data. The DIR separates the Surround Sound protocol Data (e.g. AC-
3, and DTS) from the S/P DIF signal and outputs it to the Digital Audio Decoder for further processing. The DIR
also produces the following clock signals: Master Clock(CK OUT, or MCLK), Bit Clock(BCK) and Left and Right
Channel Clock(LRCK), which are used by IC1301, IC1401 and IC1503 for processing the data. IC1101 will
generate and System Mute the same as IC1201 if an error occurs.

IC1301 Digital Audio Decoder (DAD)

The DAD takes the Surround Sound protocol data (AC-3, or DTS on input SDIA0, pin84) from the DIR and
decodes it into Front L/R, Center/Subwoofer and Rear L/R channels. The output pins are as follows: DATA0
(pin24) is Front L/R, DATA1(pin23) is Center/Subwoofer, and DATA2(pin22) is Rear L/R. The Analog Stereo
inputs are first digitized by the CODEC and then inputted to the DAD at SDIA1 pin85. Because this is a 2 channel
signal, only DATA0 (pin24, Front L/R) will be active. DATA1 and DATA2 will be inactive.

IC1401 Audio DSP

The Front L/R, Center/Subwoofer and Rear L/R data from the DAD is inputted to the DSP on pins 117(SIA),
118(SIB) and 119(SIC) respectfully. The DSP performs the necessary processing to produce the chosen sound
field. The desired sound field is chosen via the front panel controls. The front panel settings are stored in the
Display Mode control (IC102). IC1201 and IC201 exchange this initial setting data when the receiver is turned
ON via the power button on the front panel. The DSP uses the SRAM (IC1402) for temporary storage while the
data is being processed for reverberation effects.

IC1503 Audio CODEC

The CODEC performs all the digital to analog, and analog to digital conversions, and separates the combined
Front L/R, Rear L/R and Center/Subwoofer signals into their individual components (FL, FR, RL, RR, C and W),
which will then be applied to the respective speakers amplifier circuits. The stereo analog signal input is also
applied to the CODEC to be A/D converted. It is then sent to the DAD to be converted to the Front L/R signal.

IC1403 SRAM (Static RAM)

The DSP employs SRAM for temporary storage for data being processed for the sound field reverberation
affects, e.g. Cinema Studio (reverberation). All other sound field effects, e.g. 3D, are performed by IC1401
internal 16M DRAM.
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