The 12.5T Modulated Sine-Squared Pulse for NTSC

In 1965 P. Wolf of the Institute fur Rundfunktechnik, Munich, Germany, made a significant contribution to the measurement of encoded color television signals with his introduction of the 20T modulated sine-squared pulse. It possesses the ability to measure relative chrominance gain and delay, or color misregistry. This signal enjoys widespread operational use abroad. Interest in a modulated sine-squared test signal for NTSC is at present quite significant. A properly scaled test signal for NTSC is presented. The proposed signal is properly called 12.5T modulated sine-squared pulse. Compared to a 20 T, it offers: 1) an increased sensitivity to relative chroma delay, and 2) a simple scale factor for 12.5T; ¿= 10d, and for 20T; ¿=15.9d. Nomographs are provided for both the 20T and 12.5T modulated sine-squared pulses for NTSC. Mathematical derivation for the waveform distortion as a function of delay distortion is given in terms of the significant pulse parameter.