TELEFUNKEN Semiconductors
TDA4474
7. Without control voltage at Pin 16 (open circuit) the L’ switch is not active.
Standard switch, Pin 15
L’/VIF input switch, Pin 16
Ext. voltage at VIF input 2
Pin 10 or 11
Modulation
Standard
Active VIF input
Mode 1: neg. modulation (B/G)
2.0 V – Vs
3.4 V – 4.5 V 0 – 3.1 V
Á (or Pin 16 open)
open 1 V open
1V
ÁÁ ÁÁ ÁÁ neg
neg. neg
B/G .. B/G,. B/G,
*)
*)
VIF1 VIF1 VIF2
*)
Mode 2: pos. modulation (L)
0 – 0.8 V
3.4 V – 4.5 V
Á (or Pin 16 open)
open 1 V
Á Á neg. neg
L
L
VIF2 VIF1
0 – 3.1 V
open
Áneg
L
VIF2
1V
Áneg
L’
VIF1
*) condition not useful
8. Picture carrier PC = 38.9 MHz; sound carrier SC1 = 33.4 MHz, SC2 = 33.16 MHz;
PC/SC1 =13 dB; PC/SC2 = 20 dB; PC unmodulated (equivalent to sync peak level)
9. Sound carrier SC = 32.4 MHz, modulated with fmod = 1 kHz, m = 54 %; vin = 10 mV
10. Without control voltage at Pin 3 (open circuit) the SIF input 1 is automatically selected
SIF 2
30
29
AF Intercarrier
(AM) (FM/NICAM)
Loop
+VS
comp.
10 kW
28
27
26
25
AFC
24
AFC
switch
Loop
filter
6.8 pF
LVCO
150 W
CVCO
470 nF
23
22
21
20
Black
level
CRef
2.2 mF 470 nF
19
18
17
L’ and
VIF input
switch
16
TDA4474
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
SIF 1
SIF
Input switch
10 mF
AGC (SIF)
2.2 mF
AGC (VIF)
VIF 1
VIF 2
10 kW
Tuner
delay
Tuner
AGC
Standard switch
(neg/pos)
Video
*) External L/C circuit (VCO: 38.9 MHz) with TOKO coil 7KN (9 turns, 0.12mm)
Figure 3. Test circuit
Rev. A1: 17.08.1995
Preliminary Information
11 (17)