U4488B
Description
The U4488B is an integrated bipolar circuit for full multistandard 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 design 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 symmetrical 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 plete 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 VS 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...
