AD724JRZ (ANALOG DEVICES)

The AD724JRZ is a RGB to NTSC/PAL Encoder that converts red, green and blue colour component signals into their corresponding luminance (baseband amplitude) and chrominance (subcarrier amplitude and phase) signals in accordance with either NTSC or PAL standards. These two outputs are also combined to provide composite video output. All logical inputs are TTL, 3 and 5V CMOS compatible. The AD724 may be powered down when not in use. The AD724's on-chip oscillator generates the necessary subcarrier clock. The AD724 contains decoding logic to identify valid horizontal sync pulses for correct burst insertion. Delays in the U and V chroma filters are matched by an on-chip sampled-data delay line in the Y signal path. To prevent aliasing, a prefilter at 5MHz is included ahead of the delay line and a post-filter at 5MHz is added after the delay line to suppress harmonics in the output.