I am using the Sony CXA1645P RGB encoder chip. It says both sine wave and pulse can be input as a subcarrier. I was wondering if there is a microchip that will make the subcarrier signal for me?
For NTSC use, you need a 3.579545 MHz oscillator, which can be a crystal controlled colpitts, transistor based. Check the Amateur Radio handbook for circuits. They are pretty simple. There will be impedance in the emitter, either just a resistor, or a resistor in series with an inductor. There will also be two capacitors, one between the collector and emitter, the other between the emitter and ground. You may need to play with the values for the best output and operating frequency. Component values for the 80 meter amateur band will be very close to what you need. The output is generally taken from the emitter and can be squared up if you want to do it with an HC or HCT "tiny logic" IC.
Sony has a bad habit of discontinuing chips just when you need them most. If you face that problem, the NTE879 appears as if it will fill your need if it is one of a type. NTE pricing is not low. It takes RGB inputs. There are other chips that take YC type inputs, but its been some years since I worked with them. Philips Semiconductor (recently changed name to NXP) was/is a major player in the entertainment electronics chip field, including both NTSC and PAL television.
NTE parts, as you probably know, are rebrands of prime parts. The real advantage is that they are usually readily available.
Need Help With Subcarrier Colorburst
Re: Need Help With Subcarrier Colorburst
