CMX808AE3 CML Microcircuits, CMX808AE3 Datasheet - Page 9

• Manufacturer Part Number: CMX808AE3
• Description: Family Radio CTCSS Type 2 Encoder and Decoder
• Manufacturer: CML Microcircuits

Family Radio CTCSS 'Type 2' Encoder and Decoder
RX BPF ENABLE
(Bit 6)
BPF UN-MUTE
(Bit 5)
AUDIO
ATTENUATION
(Bits 4, 3, 2, 1, and 0)
1999 Consumer Microcircuits Limited
When this bit is “1” the audio band-pass filter is enabled and the output of the
filter is switched to RX AUDIO OUT. The output is then controlled by BPF UN-
MUTE. See Bit 5 below.
When this bit is “0” the audio band-pass filter is disabled (powersaved) and the
output of the filter is disconnected from RX AUDIO OUT, which is then in a high
impedance state.
When this bit is “1” and TX BPF ENABLE is “1” the audio band-pass filter
output is switched to the TX AUDIO OUT pin. When this bit is “0” the output of
the filter is disconnected from TX AUDIO OUT, which is then in a high
impedance state.
This control, along with TX BPF ENABLE, allows the filter to power up and
settle internally before switching the output on, when coming out of powersave.
When this bit is “1” and RX BPF ENABLE is “1” the audio band-pass filter
output is switched to the RX AUDIO OUT pin. When this bit is “0” the output of
the filter is disconnected from RX AUDIO OUT, which is then in a high
impedance state. This control, along with RX BPF ENABLE, allows the filter to
power up and settle internally before switching the output on, to avoid clicks
when coming out of powersave.
These five bits are used to set the attenuation of the audio volume control
according to the table below:
4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Bits
2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
9
Attenuation
Off (V
Audio
48.0dB
46.4dB
44.8dB
43.2dB
41.6dB
40.0dB
38.4dB
36.8dB
35.2dB
33.6dB
32.0dB
30.4dB
28.8dB
27.2dB
25.6dB
24.0dB
22.4dB
20.8dB
19.2dB
17.6dB
16.0dB
14.4dB
12.8dB
11.2dB
9.6dB
8.0dB
6.4dB
4.8dB
3.2dB
1.6dB
0dB
BIAS
)
CMX808A
D/808A/5