Audio/Video Processing Block

The RF / eye pattern signal is processed by several blocks to recover the audio and video signal that is output the rear panel.

Optical Device

The optical device contains an active amplifier and matrix to produce a low noise RF or eye pattern signal from the A-H detector’s signals. The RF and A-H detector signals are all input to the RF amplifier IC001.

RF Amplifier IC001

The RF signal is amplified when small, and limited when large, to equalize the eye pattern signal that is applied to the next A/V stage. The A-H detector signals are matrixed in the RF amplifier to produce servo signals like focus error (FE), tracking error (TE), track zero crossing (TZC) and PI and Mirror signals for disc identification. These signals go to the servo IC.

ARP2 IC303

The Advanced RF Processor (ARP2) IC303 receives the analog eye pat- tern data and first converts it into a digital waveform by “slicing” it across the middle. A voltage above the middle becomes a HIGH output and a voltage below becomes a LOW voltage. The HIGH and LOW voltage begin their digital journey within IC303. To support the digital signal a clock is made from the input signal.

How successful the data locks to the internal PLL to make this clock can be monitored at the JITTER pin 57 of IC303. A low voltage proves a lock. This means the servos are OK and the signal processing is OK to this point. A high voltage means the input eye pattern should be examined again. A clear (no noise) signal means the servos are OK and the disc signal is incorrect or IC303 is not able to lock onto the input signal (IC303 or its support parts are defective).

Additional signal processing within IC303 unscrambles the digital data and channels the CD and DVD data into separate output ports. Both outputs are fed to separate A/V Decoder IC401 inputs.

A/V Decoder IC401

The CD and DVD input signals undergo separate processing. The CD audio is virtually untouched and leaves the IC in the audio processing path to IC501.

The DVD video signal is MPEG decompressed using two external SDRAM ICs (not shown) for momentary storage during the processing. The subpicture (subtitle and DVD disc menu) pieces of data are loaded into memory and when called for, added into the main picture. The digital information is returned to analog form by the internal D/A converter. The DVD player’s menu is added as an on screen display (OSD) just before the analog video leaves IC401.

The DVD audio signal is also MPEG decompressed and the PCM is ex- tracted to take the route out of IC401 through IC501 and IC902 for the analog audio processing. Dolby digital AC-3 decompression takes place in this IC401 using the two external SDRAMs (not shown) that are also used for video decompression. IC401 first recognizes the 5.1 channel AC-3 or DTS data and informs Syscon IC202.

Audio DSP IC501

IC501 Audio Processing

CD	DVD	DVD with AC-3

Rear channel delay	Rear channel delay	Pass through of the
(Digital Cinema	(Digital Cinema	5.1 channel AC-3
Sound / VES)	Sound / VES)	signal

Dolby Prologic	Dolby Prologic	Downmixing of 5.1
Decoding	Decoding	channel AC-3 to 2
		channels.

Dolby Surround	Adds DTS flag to the	Signal balancing
	digital output

		Test tone generation

The outputs are digital signals to the rear panel coax and optical ports and digital signals to the D/A converters IC902, IC905-7.

D/A Converters

IC902 receives the digital signals for the analog L/R channels. The re- mainder of the converters, IC905-7, is used for the 5.1 channel digital conversion to analog signals.