NJM2208

The NJM2208 has the following features including Acts by Digital Control Signal;Single 5.0 Vdc Supply Operation for NMOS and TTL Compatibility;Minimal External Components;Low Power Dissipation;Linear Clwoma Modulators for hligb Versatility;Composite Video Signal Generation Capability;Ground-Referenced Video Prevents Overmodulation;Internal Sound Carrier Oscillator;Video Signal Encoder Capability;Package Outline ;Qipolar Technology.

The NJM2208, an integrated circuit used to generate an RF TV signal from baseband color-difference and luminance signals.The NJM2208 contains a chroma subcarrier oscillator, 3.58MHz oscillator, 4.5MHz oscillator, 3.58MHz lead and lag network, an RF oscillator, sound carrier oscillator, and a TTL compaible clock driverwith adjustable duty cycle.This device may also be used as a general-purpose modulator with a variety of video signal generating devices such as video games, test equipment, video tape recorders, etc.NJM2208 produces color difference signals and luminance signal from microcomputer output signals RGB, clock,and hold signals through the matrix circuit, and also produces the TV RF signal or video base band signal.Sound Carrier Input is also added to this IC, and a color TV RF modulator is composed by adding the video and sound carrier tank LC andncrystal oscillator.Since signals are present in the VHF band, the PCB patterns should be not long at pins 15 and 16,and a bypass capacitor should be connected to the power supply without fail. In addition, three oscillation signals should be isolated enough from each other with a sufficient mounting section interval.

NJM2208 can also be taken as the video base band output as well as the RF output. In order to convert the RGB output signals from the microcomputer into the color difference signals and luminance signal, they are converted by the matrix circuit and connected to the color input terminals of NJM2208. This IC serves as a color encoder. TV images become clear, because neither RF modulation nor RF demodulation is done. For this purpose, remove the LC from pins  15 and 16, and connect the diode instead ,so that the differential voltage in IC is Fixed to drive IC as an amplifies.