Abstract: A method for converting line sequential color signal to simultaneous signal is attained by selecting two color signals alternately every one horizontal scanning period. The color signals are applied to a balanced modulator. Two carriers with different phases are alternately switched every one horizontal scanning period and supplied to the balanced modulator to form carrier color signals with different phases every one horizontal scanning period. There are two carrier color signals of which one is a through carrier color signal and the other is produced by delaying the phase of the through carrier color signal by one horizontal scanning period then phase-shifting by 180 degrees. In an alternative embodiment, two balanced modulators are employed and a delayed replica of the color signals is applied to the second of the two modulators. Two carrier color signals are outputted from the two balanced modulators, and are mixed to produce simultaneous signal.

Abstract: An identification signal is produced on the basis of the difference between the potentials in the adjacent horizontal blanking periods of a demodulated line sequential color signal. Therefore, a delay, if, of the discrimination timing can be substantially ignored when compared to the system using narrow-bandpass filters, and the color signals can be accurately discriminated without delay. Further, by the virtue of the provision of the horizontal scanning period rate conversion circuit, a pulse which is synchronous with the horizontal signal and appears accurately at the time interval of one horizontal scanning period is based on for effecting the accurately desired discrimination, so that the discrimination can be reliably effected at the desired position without an adverse effect of noise, a dropout in magnetic recoding or the like.

Abstract: Disclosed is a method for conversion from a field signal to a frame signal in which a field signal delayed by a 1/2 horizontal scanning period and the field signal not subjected to the delay are alternately selected at a time interval of one vertical scanning period by changing over a switch. In the conversion method, the switch is changed over under control of a switching pulse which rises to its high level before the period of preceding equalizing pulses in one field, remains in the high level for one vertical scanning period, then falls to its low level, rises to its high level again during the period of preceding equalizing pulses in the next field, and falls to its low level again during the period of succeeding equalizing pulses and which repeats the above state at a time interval of two vertical scanning periods.

Abstract: An apparatus for converting field video signals into frame video signals includes a modulation circuit for modulating a chrominance subcarrier with a color signal contained in a field video signal, a signal composing circuit for combining the modulated subcarrier with a luminance signal of the field video signal, and a signal converter circuit means for producing a frame video signal including interlaced fields with a time delay applied to alternative one of the fields of the output signals delivered from the signal composing circuit. The time delay is substantially equal in period to half a horizontal scanning time period.