Pioneer DVL-909 Manual de serviço - Página 12

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DV-505, DVL-909, DV-S9

2.2 DIRB BLOCK (DIRB ASSY)

(DV-S9 ONLY)

The two major purposes of the DIRB block are the following:

(1) Switching between data reproduced from a disc and a data signal

in DAC mode

(2) Data decoding in external input mode (DAC mode)

(1) Switching Between Data Reproduced from a

Disc and a Data Signal in DAC Mode

The signal switching is performed at IC811, sending 3-line data

(LRCK, BCK and DATA) to the AUDIO Assy. The switching

control line (DAC MODE) is supplied from the DVD MAIN Assy.

The master clock (MCK) is generated by a crystal on the AUDIO

Assy when reproducing a disc, and by IC861 in DAC mode. MCK

is sent to the AUDIO Assy via RXP.

(2) Data Decoding in External Input Mode (DAC

Mode)

When the user selects DAC mode, the DAC MODE port is set to H

and VCO in IC861 starts oscillating. (VCO does not oscillate in

any other modes than DAC mode.) When there is a toss link of an

external input or a coaxial digital input, the digital input signal is

sent to IC861 from RXP of CN801, generating 3-line data

corresponding to the input sampling frequency. At the same time,

the master clock (MCK) to be used in DAC mode is also generated.

For a 96kHz input, the MCK frequency is divided by 2 by IC831.

When the user selects the internal clock as the system clock, the

clock generated by the crystal on the AUDIO Assy is sent to the

DVD MAIN Assy. When the user selects an external sync as the

system clock, the following parameters are used.

16M clock in

18M clock in

FS(kHz)

the AUDIO Assy

Oscillates

44.1

Stops oscillating

Oscillates

Stops oscillating Crystal 16M clock

Oscillates

Stops oscillating Crystal 16M clock

If there is no external input or locking onto the input digital signal

cannot be achieved, the ERR signal at pin 43 of IC861 is set to H,

and the crystal in the AUDIO Assy immediately starts oscillating.

In such cases, the clock sent to the DVD MAIN Assy will always be

a crystal clock.

IC901 16M Selector

IC902 18M Selector

IC811 Data Selector

IC861

DIR

CN801

16M clock sent to

18M clock sent to

the DVD MAIN Assy the DVD MAIN Assy

Crystal 16M clock Crystal 18M clock

DIR 16M clock

Crystal 18M clock

DIR 18M clock

IC831

Clock Selector

IC835

1/2 Divider

CN811

2.3 96K, 24-Bit, HIBIT LEGATO S

SYSTEM (AUDIO ASSY)

All 16-bit and 20-bit sources are converted to 24-bit data by IC101,

which lets a 24-bit data pass through.

As PCM1702P is a 20-bit D/A converter, processing of the upper

20 bits is assigned to it by the shift register.

The lower 4 bits are converted from serial to parallel, then the

significance of each bit is converted digital to analog, functioning

as a 4-bit D/A converter for the lower 4 bits.

By adding the lower 4 bits to the upper 20 bits in the low-pass &

ADD block, D/A conversion is achieved for 24 bits.

Hi Bit

IC101

Legato S

IC111

Shift Register

TC74HC164AF

D/A Converter

PCM1702P

Low-pass

& ADD

Analog Output

Serial to Parallel

and Significance

Conversion

TC74HC163AF