A Method of Obtaining the Advantages of I and Q Detection with Direct or Color Difference Type Demodulators
Norman W. Parker · IEEE Transactions on Broadcast and Television Receivers · 1968
A system for transforming the NTSC color signal into a double sideband subcarrier signal is described in this paper. The system operates to restore the lost upper sidebands of the "I" signal by modulating a double frequency color carrier with the I information. The system has the advantage of being applicable to direct color decoders.