Delta Signal Modulation And A/D Converter - Sony STR-DE845 Training Manual

SUPER AUDIO CD
RECORDING PROCESS
Input
Delta
Signal
Sigma
∆ Σ
Modu
-lator
(Noise Shaping)
CONVENTIONAL CD
RECORDING PROCESS
Input
Delta
Signal
Sigma
∆ Σ
Modu
-lator
(Noise
Shaping)
FIGURE 13-2 - DIFFERENCES IN RECORDING -TO- PLAYBACK PROCESSES FOR
Delta Signal (∆Σ) Modulation and A/D Converter
As shown in 13-3, the 1-bit quantiser decimates incoming analogue signals at a standard level and outputs these
signals as one of two values, "0" or "1" (1 bit). Suppose that we input sine waves into this 1-bit converter. As
shown in Figure 13-4, the portion above the base level is output as "1", while the portion below the base level is
output as "0". The result is a square wave output.
BASE
LEVEL
64fs
1 bit
Decimation
Digital
Filter
fs
64fs
16 bit
1 bit
SUPER AUDIO CD AND CONVENTIONAL CD
INPUT SINE WAVE
ONE
SAMPLING
INTERVAL
1
BASE LEVEL
0
ONE SAMPLING
INTERVAL
FIGURE13-4 - OUTPUT FROM 1-BIT QUANTISER
PLAYBACK PROCESS
Super
Audio
CD
PLAYBACK PROCESS
Interpol
CD
-ation
Digital
Filter
fs
16 bit
1 BIT QUANTIZER OUTPUT WAVE
BASE
LEVEL
SAMPLING
INTERVAL
SAMPLING RATE
COMPARISON OF
INPUT & OUTPUT
QUANTIZATION NOISE
49
13. Super Audio Cd
Analog.
Low -
Pass
64fs
Filter
1 bit
Delta
Analog.
Sigma
Low -
∆ Σ
Pass
Modu
Filter
-lator
64fs
8fs
(Noise
1 bit
24 bit
Shaping)
Note fs: 44.1kHz
ONE
SAMPLING RATE
13.3A124 1393
Output
Signal
Output
Signal
13.2A124 1393 11/27/01
1/21/02