MARANTZ SR7000
Service Manual

12. TECHNICAL DESCRIPTION FOR DECODER
This product has a decoder for Dolby Digital (AC-3) and DTS (Digital Theater System). So Multi channel sound is reproduced by connecting with DVD player or LD player. Also Dolby Pro Logic decode is available to analog audio and PCM digital audio. Additionally, 96kHz PCM stereo audio playback is possible. Decode circuit is consist of 4 ICs (DIR, DSP, CODEC, and CPU). DOLBY DIGITAL (AC-3) Dolby Digital delivers six totally separate (discrete) channels of sound.Like Dolby Surround Pro Logic, it includes Left, Center and Right channels across the front of the room. Dolby Surround Pro Logic provides a single limited-bandwidth (100Hz to 7,000 Hz) surround channel which is typically played back in the home through two channels of amplification and two speakers. In comparison, Dolby Digital provides separate (discrete) left surround and right surround channels, for moreprecise localization of sounds and a more convincing, realistic ambience. And, with Dolby Digital, all five main channels arefull range (3 Hz to 20,000 Hz). A subwoofer could be added to each channel,if desired. The sixth channel, the Low Frequency Effects Channel, will, at times, contain additional bass information to maximize theimpact of scenes such as explosions, crashes, etc. Because this channel has only a limited frequency response (3 Hz to 120Hz), it is sometimes referred to as the ".1" channel.When added to the 5 full range channels, the Dolby Digital system issometimes referred to as having "5.1" channels. DTS An amazing new technology for surround-sound entertainment, DTS Digital Surround is an encode/decode system that delivers six channels (5.1) of master-quality, 20-bit audio.In the encoding process, the DTS algorithm encrypts six channels of 20-bit digital audio information in the space previously allotted for only two channels of 16-bit linear PCM. Then during playback, the DTS decoder reconstructs the original six channels of 20-bit digital audio. Each of these six channels is audibly superior to the 16-bit linear PCM audio found on conventional compact discs. DIR (Digital audio Interface Receiver) This circuit extract synchronized clock signals and data from SPDIF signal input. QR01 (CS8414)generates these signals, this chip supports 96kHz sample rate. DSP (Digital Signal Processor for Dolby Digital/Pro Logic/DTS) Q601 (YSS912) decode 6 channels audio from encoded data signal input. Some effects are processed in addition to multi channel decode on HALL, MATRIX, and MOVIE mode. DAC (Digital to Analog Converter : QD01 /AD1855)* The AD1855 is a high performance, single-chip stereo,audio DAC.This chip are used for FRONT L/R channel. Multi channel CODEC (2 channel ADC & 4* or 6 channel DAC) 2 channel ADC and 4 channel DAC are in QK04 (AK4526). 4* or 6 channel analog audio signals (Front L/R SURROUND L/R, CENTER, LEF) are coverted from output data of DSP. Digital signal is converted from analog audio input for Pro Logic or other effect mode. SUB CPU (Q691:uPD78018FGC) This chip controls ICs in P604 and comunicate with QU01. Connect to QU01 with serial interface lines.

* : SR8000 only

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