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The EL4583 extracts TIming from video sync in NTSC, PAL,and SECAM systems, and non standard formats, or fromcomputer graphics operaTIng at higher scan rates. TImingadjustment is via an external resistor. Input without validverTIcal interval (no serration pulses) produces a defaultvertical output.Outputs are: composite sync, vertical sync, filter, burst/backporch, horizontal, no signal detect, level, and odd/evenoutput (in interlaced scan formats only).The EL4583 sync slice level is set to the mid-point betweensync tip and the blanking level. This 50% point is determinedby two internal sample and hold circuits that track sync tipand back porch levels. It provides hum and noise rejectionand compensates for input levels of 0.5V to 2.0VP-P.A built in filter attenuates the chroma signal to prevent colorburst from disturbing the 50% sync slice. Cut off frequency isset by a resistor to ground from the Filter Cut Off pin.Additionally, the filter can be by-passed and video signal feddirectly to the Video Input.The level output pin provides a signal with twice the syncamplitude which may be used to control an external AGCfunction. A TTL/CMOS compatible No Signal Detect Outputflags a loss or reduction in input signal level. A resistor setsthe Set Detect Level.
