
Application Circuit
TL/H/7509–4
FIGURE 3
IC External Components
(See Application Circuit)
Component
C1
C2
C3, C4
C5
C6
C7
C8
C9
C10
C11
C12
C13
R1
R2, R3
R4
R5
R6
R7
R8
R9
Typical Value
Comments
0.01
m
F
0.01
m
F
0.01
m
F
10
m
F
0.01
m
F
50
m
F
2.2
m
F
5
m
F
0.1
m
F
0.01
m
F
25
m
F
0.01
m
F
Tuner Dependent
Tuner Dependent
Meter Dependent
5k1
25k
5k
10k Pot
12k
AC coupling for wide band AGC input
Buffer and AGC supply decoupling
IF decoupling capacitors
Meter decoupling capacitor
AC coupling for IF output
Regulator decoupling capacitor, affects S/N floor
Level mute/stop time constant
AFT decoupling, affects stop time
Disables noise mute/stop
AC coupling for noise mute/stop threshold adjust
Supply decoupling
AGC output decoupling capacitor
Wide band AGC threshold adjust
Gain set and bias for IF; R2
a
R3
e
330
X
to terminate ceramic filter
Sets full-scale on meter
Deviation mute/stop window adjustment
Mute/stop filter, affects stop time
Level mute/stop threshold adjustment
Level mute/stop threshold adjustment
Noise mute/stop threshold adjustment, decrease resistor for lower
S/N at threshold, for optimum performance over temp. and gain varia-
tion, set this resistor value so that the signal level mute/stop threshold
occurs in the radio at 45dB S/N (
g
3 dB) in mono.
Load for open-collector stop output
AGC output load resistor for open-collector output
Sets Q of quadrature coil affecting THD, S/N and recovered audio
Optimises minimum THD
Sets signal swing across quadrature coil, High Q is important to mini-
mize effect variation of Q has on both minimum THD and AFT offset.
R10
R11
R12
R13
L1
10k
50k
3k9
62
X
18
m
H Q
u
l
50
@
10.7 MHz
TDK Electronics
TPO410-180K or equivalent
Q
u
l
70
@
10.7 MHz, L to
resonate w/82 pF
@
10.7 MHz
TOKO KAC-K2318HM or
equivalent
TL/H/7509–5
T1
10.7 MHz quadrature coil: Q
UL
l
70
CF1, CF2
10.7 MHz ceramic resonators provide selectivity; good group delay
characteristics important for low THD of system
Murata SFE10.7ML or equivalent
5