Abstract: A video signal synthesizer operable to provide a multiplex video signal for producing a picture-in-picture effect on a display screen of a display device, for example, a cathode ray tube. The video signal synthesizer utilizes a PLL (phase-locked loop) circuit to generate a carrier signal synchronized with a color burst signal contained in the composite video signal for the reproduction of the main picture. The carrier signal is first delayed by a delay circuit and then utilized to remodulate the sub-picture signal which has been compressed with respect to time. This remodulated sub-picture signal is then subjected to time-division multiplexing through analog switch assembly. The delay time of the delay circuit is set so that both color subcarrier signals of the main picture and sub-picture signals may be matched in phase. Hence, the time-division multiplexing of the main picture signal and the sub-picture signal is possible without altering the characteristics of the color composite video signal.

Abstract: A video signal synthesizer for producing a picture-in-picture effect on a display device utilizes a phase locked loop circuit to generate a carrier wave synchronized with a color burst signal of a composite video signal representing a main picture to be reproduced, which carrier wave is used to modulate a time compressed second composite signal which represents a sub-picture to be superimposed on the main picture. A time division multiplexer is used to multiplex the first and time compressed second video signals to produce a picture-within-a-picture video signal for application to the receiver of a display device. By using a carrier wave generated from a phase locked loop circuit, the color subcarrier signals of both the main and sub-picture signals have the identical frequency.

Abstract: A control apparatus of a transistor motor comprises an addition reference setting circuit (203), a positive voltage addition circuit (204 and 207), a negative voltage addition circuit (205), and a positive/negative voltage addition circuit (202). The addition reference setting circuit (203) is adapted to produce reference values VC and VD. The addition is made of the magnitude of the positive-going component with respect to the reference value VC out of the peak values of the feedback voltages (VU, VV and VW) in the positive voltage addition circuit, whereby the output VAA is provided. Addition is also made of the magnitude of the negative going component with respect to the reference value VD out of the peak values of the feedback voltages in the negative voltage addition circuit, whereby the output VB is provided. The above described outputs VAA and VB are added to each other in the positive/negative voltage addition circuit, whereby the output VE is provided.

Abstract: A video signal synthesizer operable to provide a multiplex video signal for producing a picture-in-picture effect on a display screen of a display device, for example, a cathode ray tube. The video signal synthesizer utilizes a PLL (phase-locked loop) circuit to generate a carrier signal synchronized with a color burst signal contained in the composite video signal for the reproduction of the main picture. The carrier signal is first delayed by a delay circuit and then utilized to remodulate the sub-picture signal which has been compressed with respect to time. This remodulated sub-picture signal is then subjected to time-division multiplexing through analog switch assembly. The delay time of the delay circuit is set so that both color subcarrier signals of the main picture and sub-picture signals may be matched in phase. Hence, the time-division multiplexing of the main picture signal and the sub-picture signal is possible without altering the characteristics of the color composite video signal.