PLL Tuned UHF Audio/Video Modulator ICs for PAL, SECAM and NTSC TV Systems
These modulator circuits are intended for use in VCRs, satellite receivers, set–top 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 modulator 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 on–chip video test pattern generator may be switched in with a 1.0 kHz audio test signal.
• Channel 21 through 69 UHF Operation (471 MHz to 855 MHz)
• On–Chip Low Power Operational Amplifier for Direct Tuning Varactor Voltage
• Single–Ended Output for Low Cost and Ease of Interface
• Low External Component Count
• High Speed I2C Bus Compatible
• Programmable Video Modulation Depth (8 Steps of 2.5%)
• Programmable Picture/Sound Carriers Ratio and Audio Sensitivity (8 Steps of 1.0 dB)
• On–Chip Programmable Sound Subcarrier Oscillator (4.5 MHz to 6.5 MHz)
• On–Chip Video Test Pattern Generator with Sound Test Signal (1.0 kHz)
• VCC Standby Mode (Typ 500 µA)
• Transient Output Inhibit During PLL Lock–Up at Power–On