PLL Tuned UHF and VHF Audio/Video High Integration Modulator

The MC44BS373CA is a multi-standard, PAL/SECAM/NTSC modulator.

The channel is set by an on-chip high-speed I²C compatible bus receiver. A phase-locked loop (PLL) tunes the modulator over the full UHF range.

The modulator incorporates a sound subcarrier oscillator and uses a second PLL to derive 4.5, 5.5, 6.0, and 6.5 MHz subcarrier frequencies. These frequencies are selectable by bus.

The modulation standard can be chosen using a control bit that selects between positive and negative modulation.

The picture-to-sound ratio may be adjusted using the bus. In addition, an on-chip video test pattern generator can be switched ON with a 1 KHz audio test signal.