View saa5231 datasheet:

SAA5231 DATA SLICER FOR TELETEXT PROCESSOR SEPARATION OF TELETEXT DATA FROM DESCRIPTION THE COMPOSITE VIDEO SIGNAL The SAA5231 is a monolithic integrated circuit in SEPARATION OF HORIZONTAL AND VERTI- 28 Pin DIP package designed to separate Teletext CAL SYNCHRONIZATION SIGNALS FROM signals from TV signal. THE COMPOSITE VIDEO SIGNAL EXTERNAL OSCILLATOR GENERATING 6MHz SIGNAL SYNCHRONIZED TO A MULTI- PLE OF THE LINE FREQUENCY BY PLL A 6.9375MHz CLOCK GENERATED FROM AN EXTERNAL QUARTZ CRYSTAL ”AFTER-HOURS” SYNCHRONIZATION OP- TION PROGRAMMABLE LEVELS FOR THE INPUT COMPOSITE VIDEO SIGNAL (1V OR 2.5V) PROCESSING OF EXTERNAL TELETEXT DIP28 DATA (Plastic Package) OUTPUT OF POSITIVE OR NEGATIVE SYN- CHRONIZING SIGNALS ORDER CODE : SAA5231 28 PIN DIP PACKAGE HDS2P2 TECHNO