SM-SX100
– 13 –
1-2) Application development of 1-bit coding technology
The technology has been applied in the field of AD/DA conversion device, and it is well known that "
modulation" is done
in the intermediate process of the analog signal and multi-bit signal.
Since "1-bit signal" is nearer to "analog signal" than "multi-bit signal, it has been proven that it is effective for the record/
replay format of the audio signal. It is well known that it is introduced as <Super Audio CD> in the market.
It is particularly thought that the technology to generate the 1-bit signal, "
modulation technology" is applied to the
amplifying operation. "1-bit amplifier" has been developed by directing the attention to this point.
2. Basic technological element " modulation technology"
2-1) Principle of
modulation 1-bit signal generation
<
modulation>
As the method to encode the analog signal into the 1-bit signals, "
modulation coding system" is well known.
. In this system, the analog signal waveform is traced and encoded with the step waveform as follows.
. If the upward gradient of the input signal is large, it is coded as "1".
. If the downward gradient of the input signal is large, it is coded as "0".
This method is well known.
In the other words, the 1-bit signal gained through the
modulation expresses the gradient of the analog signal, the size
of "differential value" with the frequencies of "0" and "1".
Figure 13-1 PRINCIPLE DIAGRAM OF
MODULATION
Input
Output
Integrator
Quantizer
1 sampled delay
Figure 13-2 EXPLANATORY DIAGRAM OF
MODULATION OPERATION
1Bit
Signal
Analog
Signal
Analog signal waveform
modulation
Example of 1-bit signal coding modulation
<
modulation>
It is found that "code array corresponding to the amplitude" of the original signal will be produced if the input analog signal is
previously integrated. As this block diagram is shown in Fig. 13-3, this is the basic form of "primary
modulation".
Figure 13-3 PRINCIPLE DIAGRAM OF PRIMARY
MODULATION
Q
Z
0
0
1
1
0 1 0 1 0
–1
Y
X
Input
Integrator
1 sampled delay
Quantizer
Output
1Bit Signal
Analog Signal
+
