Are post CTC4 RCA color TVs really narrow band color

[old_tv_nut]

Originally Posted by Penthode

I believe the only set which facilitated wideband color demodulation after the CTC2 was the CTC5 Deluxe. However the bandpass was vestigial sideband on both X and Z demodulation axes. This implies that there would be quadrature crosstalk. I haven't gotten around to checking or realigning the chroma channel on my CTC5. But I do detect a dark stripe between the green and magenta color bars which I assumed to be quadrature crosstalk.

It would be interesting to know the rationale behind RCA designers providing the asymmetrical +0.5/-1.5MHz chroma bandpass in the CTC5 deluxe. Curiously RCA stuck with +/- 0.5MHz on all subsequent designs up past the CTC20.

Can you post the chroma bandpass alignment procedure/waveform for the deluxe chassis? Do they show the final response for R-Y and B-Y? It might help make a guess. - can only find the super alignment online.

A dark stripe does not indicate quadrature distortion, only reduced bandwidth. Quadrature distortion would show as a residual color during the transition, with the edges of the green and magenta bars discolored one way or another.

[Edit: this also depends on whether the source is narrowband, true I/Q, or equiband wider than 0.5 MHz. If the source is real I/Q, and the receiver really has wideband demodulation on two axes, you will see more distortion on transitions that involve strong I signals. Since the green/magenta transition is mostly Q, you won't see quadrature there with a proper I/Q source, unless the receiver has phase distortions below +/- 0.5 MHz (which can happen with poor alignment or misadjusted fine tuning).]