FX828 Datasheet, PDF (6/34 Pages) CML Microcircuits – CTCSS/DCS/SELCALL Processor

CTCSS/DCS/SELCALL Processor
1.4 External Components
FX828
C1 22pF
C2 22pF
C3 100pF
C4 0.1µF
C5 100pF
C6 0.1µF
C7 Note 2
C8 0.1µF
C9 1.0 to 3.3µF
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
R1 1MΩ
R2 100kΩ
R3 100kΩ
R4 Note 2
R5 22kΩ
R6 Note 1
R7 Note 1
±5%
±10%
±10%
±10%
±10%
±10%
±10%
X1 4.032MHz
(tolerance depends upon
system requirements)
Notes: 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
=
R2
−
R6
Tx Audio Gain
=
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