U4488B
Quasi-Split Sound Circuit and AM Demodulator
Description
The U4488B is an integrated bipolar circuit for full multi-
standard sound IF signal processing in TV/VTR and
Multimedia applications. It supplies AM signals as well
as FM/NICAM sound IF signals and thus allows the de-
sign of a universal sound IF module for various
applications. The U4488B has the same performance like
the U4468B, with the additional feature of a second sym-
metrical IF input.
Features
D
5-V supply voltage; low power consumption
D
Gain-controlled 3-stage wideband IF amplifier
D
Active carrier generation by FPLL principle
(frequency-phase-locked-loop) for true quadrature
demodulation
D
Complete alignment-free AM demodulator
D
Switchable amplitude detector for gain control, which
operates as a peak detector for FM sound and as a
mean level detector for AM sound
D
Two symmetrical IF inputs
Block Diagram
IF1/IF2
S3
11
1
2
IF-Amp
12
Intercarrier
(FM)
4
14
REF
FPLL
V
S
Loop
filter
5
0°
90°
VCO
9
8
VCO
IF
FM
IF
AM
15
16
IF-Switch
Mean
3
AGC
Peak
level
13
IF AGC
Mean/peak
7
S1
Mute
AM-Det
6
AF(AM)
10
S2
13789
Figure 1. Block diagram
Ordering Information
Extended Type Number
U4488B
Package
DIP16
Remarks
TELEFUNKEN Semiconductors
Rev. A2, 15-Jan-98
1 (9)
Preliminary Information
TEMIC [ TEMIC SEMICONDUCTORS ]
