Phase Alternate Line is an encoding standard used for video recording and playback. It was developed for Analog Television Broadcast. India uses PAL-B standard.
Despite the smaller bandwidth in comparison to digital formats it is still used widely because of the simplicity and lower cost of system.
Generation of time signal can be done with microprocessor and microcontroller. There is one more advantage I have seen now a days. That if your transmission has some noise. It can still function properly.
I have used Atmel ATmega32a and Atmega16 for the generation of timing signal. But it can be done using smaller 8 bit microcontrollers.
You can generate monochromatic signal very easily. But to generate color signal your voltage levels and the color burst timing has to be dead accurate. If your generated signal has a variation other than the specified marginal limits. You will lose color information altogether.
Despite all these it is very rough and tough standard.
I have also added an esp8266 12e module for the wifi capabilities. PAL video signal generated by atmega16a.
ESP8266 12e module with AT firmware v 1.5 used for communication.