Abstract: The invention relates to a sinusoidal subcarrier phase shifter for a television color generator. In accordance with the invention, the sinusoidal subcarrier is first converted to a corresponding rectangular wave. The pulse width of the rectangular wave is then varied in accordance with a signal of varying amplitude, the amplitude of the signal corresponding with the desired phase shift. The pulse width is varied by an arrangement consisting of interconnected one shot multivibrators and operational amplifiers. The rectangular wave form is then converted to a square wave, and the square wave is, in turn, converted to a phase shifted sinusoidal wave. The phase shifter for a PAL system consists of two channels, one of the channels producing one of the PAL phases and the other channel producing the complementary PAL phase.
Abstract: The invention relates to a matrix wipe generator for television signals. With matrix switching, the television screen is divided into a plurality of blocks, and, if the screen originally contains the picture A, then picture B is switched into the blocks one at a time until all of the blocks, i.e., the whole screen, are filled with the picture B. The novel generator in accordance with the invention provides waveforms which give a Z-axis wipe effect, that is, the B picture appears to come into the screen from behind the A picture in each block.
June 26, 1978
Date of Patent:
April 22, 1980
Central Dynamics Ltd.
Raymond L. Greenfield, John G. Lauderdale
Abstract: This invention relates to a mix/effects switch arrangement and a mix/effects switching system including the switch arrangement. The mix/effects switch arrangement includes five switches each of which has two input terminals, an output terminal and a control terminal. One of the switches is the output switch, and a first and second one of the remaining switches are serially arranged to constitute an input to one of the input terminals of the output switch. The remaining two switches are serially arranged in parallel to constitute the input to the other input terminal of the output switch. At least the output switch constitutes a soft switch, and, preferably, the two input switches also are soft switches. In the switching system, a source of first background video signal is applied to one input terminal of an input switch, and a source of second background video signal is applied to one input of the other input switch.