The GS4882 and GS4982 are precision sync separators for extracting timing information from NTSC, PAL, and SECAM video signals. The GS4882 generates noise immune and temperature stable composite sync, vertical sync, back porch and odd/even field signals. The GS4982 provides a horizontal sync output for those applications requiring horizontal sync extraction.
The GS4882 and GS4982 feature an internal color burst filter for minimization of spurious timing information and the reduction of external component count. The precision 50% sync slicing feature embodied in the device provides for superior sync extraction in the presence of noise and varying sync pulse amplitudes. The high performance dual mode input clamp aids in maintaining the accuracy of the internally derived 50% sync slicing level to within ±5% as well in reducing system start-up/recovery time. In addition, a missing pulse detector enables the devices to quickly respond to impulse noise by temporarily turning on a Nosync Recovery Current connected to the dual mode input clamp. The input stage will operate with input signal amplitudes ranging from +0.5 to +4.0V peak to peak with a +5V supply voltage.
The GS4882 and GS4982 have robust signal detection and output muting circuitry. Should valid video be removed from the device input, the absence of video will be automatically detected and all outputs muted to a logic high state after a defined probation period. Upon the return of a valid video signal, device outputs are enabled after receiving 8 lines of video. An internal frequency to voltage converter also allows the device to differentiate between valid and invalid input signals by analyzing the horizontal scan rate of the input signal and comparing it against the expected input signal scan rate. The GS4882 and GS4982 are available in standard 8 pin PDIP and SOIC packages, operate with a + 4.5 to +13.2 volt supply voltage range and typically consume less than 6 mA of current with a +5 V supply voltage.
