CMX808A View Datasheet(PDF) - CML Microcircuits
Part Name
Description
Manufacturer
CMX808A Datasheet PDF : 23 Pages
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Family Radio CTCSS 'Type 2' Encoder and Decoder
CMX808A
RX BPF ENABLE
(Bit 6)
BPF UN-MUTE
(Bit 5)
AUDIO
ATTENUATION
(Bits 4, 3, 2, 1, and 0)
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:
Bits
Audio
4 3 2 1 0 Attenuation
00000
00001
Off (VBIAS)
48.0dB
00010
46.4dB
00011
44.8dB
00100
43.2dB
00101
41.6dB
00110
40.0dB
00111
38.4dB
01000
36.8dB
01001
35.2dB
01010
33.6dB
01011
32.0dB
01100
30.4dB
01101
28.8dB
01110
27.2dB
01111
25.6dB
10000
24.0dB
10001
22.4dB
10010
20.8dB
10011
19.2dB
10100
17.6dB
10101
16.0dB
10110
14.4dB
10111
12.8dB
11000
11.2dB
11001
9.6dB
11010
8.0dB
11011
6.4dB
11100
4.8dB
11101
3.2dB
11110
1.6dB
11111
0dB
© 1999 Consumer Microcircuits Limited
9
D/808A/5
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