MC1374
VCC
Figure 19. A Channel 4 Vestigial Sideband Filter
8
9
RL = 75Ω 8.2pF
24Ω
2.7k
39
pF
33pF
33pF
Both transformer windings
4T #23 AWG
close wound on 1/4″ ID
on common axis, 3/8″ spacing.
8.2pF 24Ω
33pF
24Ω
100Ω
Output
75Ω
8T #23 AWG
close wound on 1/8″ ID,
knife tuned to trap Channel 3
61.25 MHz.
0
–10
–20
–30
–40
Ch. 4 Ch. 4
–50
Pix
S
–60
–70
61 65 69 73
f, FREQUENCY (MHz)
Figure 20. Audio Pre–Emphasis Circuit
25
1
2 π RC
20
C = 0.0012µF
CC = 0.1µF
–+
14
“Flat”
Audio
Input
Audio
r = 56kΩ Input
R
6.0kΩ
5 Gnd
15
10
1
5 2 π (r + R)CC
0
1
2 π rC
–5
21
210 2100 21k
f, FREQUENCY (MHz)
Pre–emphasis = 75 µs = rC =
1
2 π (2100 Hz)
Figure 21. Crystal Controlled RF Oscillator
for Channel 3, 61.25 MHz
VCC
R1 470
C1
0.001
R2 470
61.252
MHz
R3 470
C2
56pF
Ra
180
L1
0.15µH
Rb 18
6
7
MC1374
NOTE: See Application Note AN829 for further information.
8
MOTOROLA ANALOG IC DEVICE DATA