A video to try and explain this Blonder tongue business I mention in some of my videos as a signal source at times for my TV's. Toward the end, I was confused momentarily about one of the controls on the bigger model. That is used to adjust video modulation and the other is for signal strength output. I wasn't very clear on that, but if you are not familiar with these units, I hope you learn a little something anyway.
In this video I take a Holland HPM55 A/V modulator apart to see whats inside. Pictures: http://imgur.com/a/7SVXE PIC16C54C: http://ww1.microchip.com/downloads/en/DeviceDoc/30453d.pdf