The MC44BS374T1 and MC44BS374T1A are phase-locked loop (PLL) tuned, ultra high
frequency (UHF) and very high frequency (VHF), audio/video (A/V), high integration
modulator, integrated circuits (IC). These devices are intended for use in VCRs,
games, and set-top box systems, and both use "T" software.
The MC44BS374T1 and MC44BS374T1A have the same hardware package as the MC44BS374CA.
The only difference is the software and the start up channel.
The MC44BS374T1 starts up on channel 36 (591.25 MHz) and the MC44BS374T1A starts
up on channel 71 (871.25 MHz). Both are compatible with the following formats:
- PAL—Phase Alternation Line (European TV format)
- NTSC—National Television System Committee
An on-chip high-speed I2C compatible bus receiver sets the channel. It is tuned by a PLL over the full range of the UHF bands. 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, which are selectable using the bus.
The modulation standard is chosen using a control bit that selects between System L and System B/G.
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.
The MC44BS374T1 and MC44BS374T1A are available in a 16-pin (SO16NB) package.