Signals used by color television systems to convey color information (not luminance) in such a way that the signals go to zero when there is no color in the picture. Color difference signal formats include: R-Y and B-Y; I and Q; U and V; PR and PB. The figure below shows general color difference waveforms along with the Y signal. The color difference signals must first be converted in their RGB form before they can recreate the picture. Refer to the RGB discussion to view what the RGB version of the color bar signal looks like. The color difference signals in the figure are centered around 0 volts, but this is only true for the SMPTE/EBU N10 standard. The NTSC and M11 color difference standards have the most negative portions of the color difference signals riding on a voltage of 0 volts or close to it.