The difference between the gain of the chrominance components and the gain of the luminance components as they pass through the system. The amount of distortion can be expressed in IRE, percent, or dB. The number given is negative for low chrominance and positive for high chrominance. This distortion most commonly appears as attenuation or peaking of the chrominance information that shows up in the picture as incorrect color saturation. Any signal containing a 12.5T sine-squared pulse with 3.579545 MHz modulation can be used to measure chrominance-to-luminance gain distortions. Many combination signals such as FCC Composite and NTC-7 Composite contain this pulse.