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Here is a CTCSS decoder that can Decode and Encode all standard and more PL tones. The circuit uses an MX465DW and the layout is entirely in single side surface mount technology except for the wire hookup. The chip has become rare and is not easy to acquire in low quantities, since only a few distributor have it in stock.
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5405 Morehouse Drive Suite 135
Try the above if
you want to design a CTCSS circuit with MX465DW.
Click me to get a better view.
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The schematic and
layout was created with the free eaglesoft design package. You can download the schematic and the layout by clicking at the underlined links.
There are currently two of those Enc/Dec running within the system. One of it is controlling the transmitter enable function of the repeater. Without the proper PL tone it simply prohibits the CAS signal to the repeater controller..
The other one is used in the Echo-Link interface as a positive carrier detect signal. It does not prohibit the transmitter to go on the air but it signals the echo-link software that there is a carrier with correct PL tone. The echo-link decoder is configured to be somewhat faster than the repeater which may cause a low frequency male voice to trigger falsly.. Both units work flawless, thanks to the high integration of the chip.
Bill of material for the CTCSS circuit:
|
| |
| Qty |
Value |
Device |
Parts |
| 4 |
0.1 |
C-USC1206 |
C3, C4, C5, C9 |
| 2 |
1N4148 |
DIODE-MINIMELF |
D1, D2 |
| 3 |
2.2uF |
CPOL-USA |
C1, C2, C8 |
| 2 |
2M |
R-US_R1206 |
R1, R3 |
| 1 |
2N2222 |
2N2222SOT23_BEC |
Q2 |
| 1 |
3.9M |
R-US_R1206 |
R2 |
| 1 |
4MHz |
CRYTALSM49 |
X1 |
| 4 |
10K |
R-US_R1206 |
R4, R5, R6, R7 |
| 1 |
18p |
C-USC1206 |
C7 |
| 1 |
25K |
TRIM_US-SMT |
VR1 |
| 1 |
33p |
C-USC1206 |
C6 |
| 1 |
78M05CDCYR |
78M05CDCYR |
IC2 |
| 1 |
MX465DW |
MX465DW |
IC1 |
| 1 |
SWS006 |
SWS006 |
S1 SMD Dip Switch |
Below is the table with the DIP Switch Settings for the
according Sub-audible tone.
A 1 (one) means
that the DIP Switch is in the OFF position and
a 0 (Zero) means that
the DIP Switch is in the ON position.
|
Frequency in Hertz
|
DIP1 |
DIP2 |
DIP3 |
DIP4 |
DIP5 |
DIP6 |
| 67.0
|
1 |
1 |
1 |
1 |
1 |
1 |
|
69.3 |
1 |
0 |
0 |
1 |
1 |
1 |
| 71.9
|
1 |
1 |
1 |
1 |
1 |
0 |
|
74.4 |
0 |
1 |
1 |
1 |
1 |
1 |
| 77.0 |
1 |
1 |
1 |
1 |
0 |
0 |
|
79.7 |
1 |
0 |
1 |
1 |
1 |
1 |
| 82.5 |
0 |
1 |
1 |
1 |
1 |
0 |
|
85.4 |
0 |
0 |
1 |
1 |
1 |
1 |
| 88.5 |
0 |
1 |
1 |
1 |
0 |
0 |
|
91.5 |
1 |
1 |
0 |
1 |
1 |
1 |
| 94.8 |
1 |
0 |
1 |
1 |
1 |
0 |
|
97.4 |
0 |
1 |
0 |
1 |
1 |
1 |
| 100.0 |
1 |
0 |
1 |
1 |
0 |
0 |
|
103.5 |
0 |
0 |
1 |
1 |
1 |
0 |
| 107.2 |
0 |
0 |
1 |
1 |
0 |
0 |
|
110.9 |
1 |
1 |
0 |
1 |
1 |
0 |
| 114.8 |
1 |
1 |
0 |
1 |
0 |
0 |
|
118.8 |
0 |
1 |
0 |
1 |
1 |
0 |
| 123.0 |
0 |
1 |
0 |
1 |
0 |
0 |
|
127.3 |
1 |
0 |
0 |
1 |
1 |
0 |
| 131.8 |
1 |
0 |
0 |
1 |
0 |
0 |
|
136.5 |
0 |
0 |
0 |
1 |
1 |
0 |
| 141.3 |
0 |
0 |
0 |
1 |
0 |
0 |
|
146.2 |
1 |
1 |
1 |
0 |
1 |
0 |
| 151.4 |
1 |
1 |
1 |
0 |
0 |
0 |
|
156.7 |
0 |
1 |
1 |
0 |
1 |
0 |
| 159.8 |
1 |
0 |
0 |
0 |
1 |
1 |
|
162.2 |
0 |
1 |
1 |
0 |
0 |
0 |
| 167.9 |
1 |
0 |
1 |
0 |
1 |
0 |
|
173.8 |
1 |
0 |
1 |
0 |
0 |
0 |
| 179.9 |
0 |
0 |
1 |
0 |
1 |
0 |
|
183.5 |
0 |
1 |
0 |
0 |
1 |
1 |
| 186.2 |
0 |
0 |
1 |
0 |
0 |
0 |
|
189.9 |
1 |
1 |
0 |
0 |
1 |
1 |
| 192.8 |
1 |
1 |
0 |
0 |
1 |
0 |
|
196.6 |
0 |
0 |
1 |
0 |
1 |
1 |
| 199.5 |
1 |
0 |
1 |
0 |
1 |
1 |
|
203.5 |
1 |
1 |
0 |
0 |
0 |
0 |
| 206.5 |
0 |
1 |
1 |
0 |
1 |
1 |
|
210.7 |
0 |
1 |
0 |
0 |
1 |
0 |
| 218.1 |
0 |
1 |
0 |
0 |
0 |
0 |
|
225.7 |
1 |
0 |
0 |
0 |
1 |
0 |
| 229.1 |
1 |
1 |
1 |
0 |
1 |
1 |
|
233.6 |
1 |
0 |
0 |
0 |
0 |
0 |
| 241.8 |
0 |
0 |
0 |
0 |
1 |
0 |
|
250.3 |
0 |
0 |
0 |
0 |
0 |
0 |
| 254.1 |
0 |
0 |
0 |
1 |
1 |
1 |
Good luck on the project!
KJ6ZD
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