MC44353

These modulator circuits of MC44353 are intended for use in VCRs, satellite receivers, settop boxes, video games, etc. An on chip high speed I²C compatible bus receiver is included and is used to set the channel, tuned by a PLL over the full range in the UHF bands. The MC44353 incorporates a sound subcarrier oscillator, using a second PLL to derive 4.5, 5.5, 6.0 and 6.5 MHz carrier frequencies, selectable by the bus.

For the sound, either frequency modulation with pre emphasis or amplitude modulation (MC44353 only) is possible. A control bit (MC44353 only) is used to select AM sound with positive RF modulation (system L). The level of the sound carrier with respect to the vision carrier and the modulation depth of both sound and vision may be adjusted by means of the bus. In addition, an onchip video test pattern generator may be switched in with a 1.0 kHz audio test signal.