CTCSS/DCS/SELCALL Processor
FX828
1.4
External Components
C1
C2
C3
C4
C5
C6
C7
C8
C9
Notes:
22pF
22pF
100pF
0.1µF
100pF
0.1µF
Note 2
0.1µF
1.0 to 3.3µF
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
R1
R2
R3
R4
R5
R6
R7
1MΩ
100kΩ
100kΩ
Note 2
22kΩ
Note 1
Note 1
±5%
±10%
±10%
±10%
±10%
±10%
±10%
X1
4.032MHz
(tolerance depends upon
system requirements)
1. R2, R6, R7 and C3 form the gain components for the Summing Amplifier. R6 and R7
should be chosen as required from the system specification, using the following formula:
Tx Sub Audio Gain
Tx Audio Gain
=
−
=
−
R2
R6
R2
R7
2. R3, R4, C5 and C7 form the gain components for the Rx Input Amplifier. R4 should be
chosen as required by the signal level, using the following formula:
Gain
=
−
R3
R4
C7 x R4 should be chosen so as not to compromise the low frequency performance of this
product.
Figure 2 Recommended External Components
©
2009 CML Microsystems Plc
6
D/828/4
CMLMICRO [ CML MICROCIRCUITS ]
