[old_tv_nut]

In the past few days I have experimented with hooking up a digital camera with NTSC output to my CTC-5 via a UHF modulator. The camera is an Olympus pocket point-and-shoot, model Stylus 710, 7.1 Mpixels. It has an NTSC output of the camera back LCD display. The camera has multiple resolution settings for the digital files, but they have no effect on the NTSC output. The camera back display shuts off when the dedicated cable is plugged in. The video coming out duplicates the camera back display with informative text and symbols that cannot be turned off.

The first trials yesterday, using available room light, showed terrible color, greenish faces, etc. I tried white balance settings to no avail.

Today I brought out various color charts and discovered the problem was that the CTC-5 HUE adjustment (color phase, which RCA later called TINT) was way off. I suspect this is because the color subcarrier out of the camera is off frequency a fair amount, and the CTC-5 subcarrier loop suffers from low gain, and develops a large phase offset to pull the oscillator to the incoming frequency.

Broadcast subcarrier tolerance was +/- 10 Hz, but it's doubtful the camera has a tolerance tighter than 100-150 Hz, maybe worse. I would have to hook up a frequency counter to the color oscillator in the TV to see what the frequency is with various sources, and of course I have no video source guaranteed to meet broadcast tolerance.

With hue adjusted, the color was reasonable. Other than the hue issue, the picture showed the same gray scale tracking, resolution, and brightness issues that the CTC-5 always does.

The next step in picture improvement would be to add some dedicated lighting, but I don't want the clutter in my living room and put everything away.