Prototype set is here

[Penthode]

Please find attached two papers, both from Hazeltine. The first one on general color receiver design pertains to CPA only. The last page has a nearly full CPA demodulator. Note the demodulator does not use a crystal! The design is a straight reactance controlled Colpitts oscillator. This is interesting in as much as it is expected to keep sync over the entire line from onlyeight cycles of gated burst reference! Note the color hold control- if there is no crystal on this prototype I would trust there is a color hold control on the front!

The second Hazeltine paper is by Bernard Loughlin. His name conjures up a lot of early NTSC development. His 1966 paper is timed with the launch of PAL in Europe. It is interesting to read his reflections since the NTSC did much of the earliest PAL and PAF work.

I find his interesting note in passing on the second page (numbered 154) under the heading Stationary Axis. Mr Loughlin refers to his October 1951 IRE paper whereby the R-Y axis was stationary and the B-Y axis switched or inverted 180 degrees. He goes on to state the 1952 PAF NTSC testing made the B-Y axis stationary and the R-Y axis switched. In PAL, the R-Y switches at line rate.

I would be interested to see how closely the prototype receiver follows the Hazeltine decoder.