FX465 View Datasheet(PDF) - CML Microsystems Plc
Part Name
Description
Manufacturer
FX465 Datasheet PDF : 9 Pages
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Application Information ......
Description
Voice on shared radio channels is multiplexed with a subaudible CTCSS (Continuous Tone Controlled Subaudible
Squelch) tone as a means of directing messages among user groups sharing the same RF frequencies. CTCSS
modulates the transmitter with a discrete tone, from 39 standard CTCSS tones in the range (67.0Hz to 250.0Hz) accord-
ing to TIA/EIA-603. There are an additional eight CTCSS tones not specified in TIA/EIA-603 that the FX465 will encode
and decode. They are: 159.8Hz, 183.5Hz, 189.9Hz, 196.6Hz, 199.5Hz, 206.5Hz, 229.1Hz, and 254.1Hz, for a total of 47
CTCSS tones plus NOTONE.
The FX465 also incorporates Tx/Rx on chip speech filters. In early CTCSS designs, Tx speech was not filtered from
the CTCSS tone, rather the filtering was dependent upon the host transmitters pre-emphasis network. At only 6dB/
octave, the attenuation of speech components at higher CTCSS tones was only a few dB which resulted in talk-off (low
frequency voice components unsquelching the receiver audio).
TIA/EIA-603
Nominal
Freq.
FX465
Freq.
∆fo %
67.0
66.98
-0.029
69.3
69.32
0.024
71.9
71.901
0.001
74.4
74.431
0.042
77.0
76.965
-0.046
79.7
79.677
-0.029
82.5
82.483
-0.021
85.4
85.383
-0.020
88.5
88.494
-0.007
91.5
91.456
-0.048
94.8
94.76
-0.042
97.4
97.435
-0.036
100.0
99.96
-0.040
103.5
103.429
-0.069
107.2
107.147
-0.05
110.9
110.954
0.049
114.8
114.84
0.035
118.8
118.793
-0.006
123.0
123.028
0.023
127.3
127.328
0.022
131.8
131.674
-0.095
136.5
136.612
0.082
141.3
141.323
0.016
146.2
146.044
-0.107
151.4
151.441
0.027
156.7
156.875
0.112
* 159.8
159.936
0.085
162.2
162.311
0.069
167.9
167.708
-0.114
173.8
173.936
0.078
179.9
179.654
-0.137
* 183.5
183.680
0.098
186.2
186.289
0.048
* 189.9
190.069
0.089
192.8
192.864
0.033
* 196.6
196.329
-0.138
* 199.5
199.312
-0.094
203.5
203.645
0.071
* 206.5
206.207
-0.142
210.7
210.848
0.070
218.1
217.853
-0.113
225.7
225.339
-0.160
* 229.1
229.279
0.078
233.6
233.359
-0.103
241.8
241.970
0.070
250.3
250.282
-0.007
* 254.1
254.162
0.024
NOTONE
Serial Input Mode
* Not specified in the TIA/EIA-603 tone set.
Table 2 Tone Programming Information
CTCSS Programming Table (All frequencies in Hertz (Hz)
D5
D4
D3
D2
D1
D0
Hex
1
1
1
1
1
1
3F
1
1
1
0
0
1
39
0
1
1
1
1
1
1F
1
1
1
1
1
0
3E
0
0
1
1
1
1
0F
1
1
1
1
0
1
3D
0
1
1
1
1
0
1E
1
1
1
1
0
0
3C
0
0
1
1
1
0
0E
1
1
1
0
1
1
3B
0
1
1
1
0
1
1D
1
1
1
0
1
0
3A
0
0
1
1
0
1
0D
0
1
1
1
0
0
1C
0
0
1
1
0
0
0C
0
1
1
0
1
1
1B
0
0
1
0
1
1
0B
0
1
1
0
1
0
1A
0
0
1
0
1
0
0A
0
1
1
0
0
1
19
0
0
1
0
0
1
09
0
1
1
0
0
0
18
0
0
1
0
0
0
08
0
1
0
1
1
1
17
0
0
0
1
1
1
07
0
1
0
1
1
0
16
1
1
0
0
0
1
31
0
0
0
1
1
0
06
0
1
0
1
0
1
15
0
0
0
1
0
1
05
0
1
0
1
0
0
14
1
1
0
0
1
0
32
0
0
0
1
0
0
04
1
1
0
0
1
1
33
0
1
0
0
1
1
13
1
1
0
1
0
0
34
1
1
0
1
0
1
35
0
0
0
0
1
1
03
1
1
0
1
1
0
36
0
1
0
0
1
0
12
0
0
0
0
1
0
02
0
1
0
0
0
1
11
1
1
0
1
1
1
37
0
0
0
0
0
1
01
0
1
0
0
0
0
10
0
0
0
0
0
0
00
1
1
1
0
0
0
38
1
1
0
0
0
0
30
1
0
Data
Clock
x
x
2X
5
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