Circuit Descriptions and Serial Control Information
...... 1
Control bits
(LSB) loaded last
0
0
1
1
0
0
1
1
Mic. Select
– Microphone Input 1
– Microphone Input 2
A multiplexed “microphone” input allowing the use
of differing type and level voice inputs.
Function
Notes
2
0
1
0
1
Input Select
– Rx Input
De-emphasis Bypass; HPF to 0dB
– Rx Input
De-emphasis Select; HPF to 0dB
– Tx Input
Powersave De-emphasis;
HPF to 14dB
– Path Input to V
BIAS
;
Powersave De-emphasis
Transmit or receive audio sources are selected,
inserting the appropriate path gain for the chosen
input.
The input path can be set to bias whilst allowing
receiver noise monitoring.
3
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
7
1
0
X
X
X
4
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
8
1
1
0
X
X
5
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
9
1
1
1
0
X
6
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
14
1
1
1
1
0
Input Gain Amplifier
– Gain Set
0.0dB
1.0dB
2.0dB
3.0dB
4.0dB
5.0dB
6.0dB
7.0dB
8.0dB
9.0dB
10.0dB
11.0dB
12.0dB
13.0dB
14.0dB
15.0dB
A gain element intended to adjust the drive level to
the compressor, catering for differing signal
sources and microphone sensitivities.
Compressor
Enabled
Powersaved
Powersaved
Powersaved
Powersaved
HPF
Enabled
Enabled
Powersaved
Powersaved
Powersaved
LPF
Enabled
Enabled
Enabled
Powersaved
Powersaved
Pre-Process Output
Enabled
Enabled
Enabled
Enabled
Powersaved
The Pre-Process Path LPF should be selected whilst CEPT ‘Response to the Tx to Mod.
frequencies exceeding 3kHz’ tests are carried out.
10
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
11
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
14
0
1
12
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
13
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Pre-Process Gain
– Gain Set
-2.75dB
-2.50dB
-2.25dB
-2.00dB
-1.75dB
-1.50dB
-1.25dB
-1.00dB
-0.75dB
-0.50dB
-0.25dB
0dB
0.25dB
0.50dB
0.75dB
1.00dB
Pre-Process Output
– Disable Pre-Process Output
Output at V
BIAS
– Enable Pre-Process Audio Output
An in-line output drive stage providing adjustable
gain or attenuation to compensate for level
tolerances in the external audio processes and
peripherals.
The output of this amplifier stage is available for
further voice (audio) processing such as
“Frequency Inversion Voice Scrambling.”
Bit 14 is the Enable/Powersave function for the
Pre-Process output stages.
See
Bits 7 8 9 14 .....
Reference ...... Figure 4
6
CMLMICRO [ CML MICROCIRCUITS ]
