A system for converting a simultaneous color picture signal of a wide band into a field sequential color picture signal of a narrow band and a system for reconverting a field sequential color picture signal of a narrow band into a simultaneous color picture signal of a wide band. The former system comprises memory means capable of varying the writing speed and the reading speed and having the memory capacity capable of storing a picture signal of one frame, means for switching two input signals to output them at every field period, means for obtaining one of the two chrominance signals of a simultaneous color picture signal at the odd numbered field and obtaining the other chrominance signal at the even numbered field by means of the switching means, and means for writing at a high speed and reading at a low speed in and from the memory means the luminance signal and the chrominance signals different at every field of the color picture signal. The latter system comprises memory means capable of varying the writing speed and the reading speed, having the memory capacity capable of storing a picture signal of one frame, capable of repeatedly reading the stored signal therefrom, and capable of simultaneously reading therefrom signals differing by one field period from each other, means for writing a signal of one frame of a field sequential color picture signal of a narrow band in the memory means at a low speed, and means for repeatedly reading the stored signal at a high speed and obtaining two chrominance signals from the simultaneously read out signals differing by one field period.

PAL colour television signals are sampled at a sampling rate which bears a ratio of small integers, e.g. 3, 5/2, to the colour subcarrier frequency, the sampling instants being maintained at points symmetrically disposed in time about the maxima and minima of the U-component of the signal. A previous sample in such a signal or a combination of such samples can be used as a reference in differential coding or a prediction for error concealment overcoming complications caused by the V-axis phase reversal on alternate lines. Similar principles can be applied to conversion between PAL and N.T.S.C. signals.

A line sequential color signal coding format for a limited bandwidth video recording system is disclosed which achieves improved vertical transient response during playback display. Spectrum interleaving is employed between the luminance signal and color difference chrominance signals during encoding, with the necessary signal separation during decoding being effected by comb filtering using delay lines. Prefiltering may be implemented during encoding to comb out crosstalk producing signals from the luminance and chrominance signal spectrums. To avoid contamination of the mixed high frequency luminance components in the decoder by the switched low frequency components, the composite signal may be fed through a high pass luminance filter in the decoder whose cutoff frequency is above that of a low pass filter in the encoder through which the switched, line sequential components are fed.

A video graphics adapter is configured to provide both parallel and sequential color components to separate display monitors. When in a first state, the video graphics adapter provides individual color components to a video-output independent of each other color component, such that an entire frame of a red component will be provided to a video-out port for prior to, or subsequently after, an entire frame of the green component being provided to the video-out port. Each color component is provided to a common port. In response to a second configuration state, a traditional parallel red, green, blue (RGB) data port will be generated in order to provide data to a display device. In yet another configuration state, both the individual color components are provided at a common port, and the individual color components are provided in parallel to an RGB port.

In a GRGB line sequential color television system, the sequential-to-simultaneous decoder in the receiver employs separate delay line and switch arrangements for each channel. Also, the sound signals associated with the green (G) portions of the sequence are transmitted in multiplex form with the other sound signals during the R and B portions of the sequence.