Akai PDP42Z5TA Service Manual page 76

DAC INFINITE ZERO DETECTION
The CE2836 DAC has an Infinite Zero Detection circuit which detects zero in the Audio Serial Port that lasts for
approximately 0.2 sec. By default, the zero detection circuit is on.
DAC Digital Attenuation
Each DAC contains an Digital Attenuation block. The attenuation values are hold in the Volume Control Registers. The Value
80H corresponds to Full Scale, 0dB. and each decrement correspond to -0.5 dB additional attenuation.
ADC Gain and ALC
Each channel of ADC input includes a Analog Gain. The Gain is controlled by CREGC, ADC Gain Selection, The gain range
is from +6 dB to -9 dB. with 1 dB step. The GAIN = 9 corresponds to 0dB gain. The AUTOMATIC LEVEL CONTROL set
the ADC maximum digital output to a prescribed value by automatic manipulating the analog gain. The ALC is controlled by
CREG8, ADC PROC. REGISTER..
ALCHTM
Table (5): ALC Target Level
ALC[2:0] Maximum Digital Output
000 -1 dB FS
001 -2 dB FS
010 -3 dB FS
011 -4 dB FS
100 -5 dB FS
101 -6 dB FS
110 -7 dB FS
111 -8 dB FS
Table (6): ALC Hold Time
Hold Time
0 340 msec.
1 5.3 msec
74／148
Comment
For music program
For speech program
CE2836