Displaying waveforms

An apparatus for generating, from a voltage waveform which repeats at a predetermined rate, a video signal suitable to cause a representation of said waveform to be displayed on a raster scan display device having a display surface, means for producing a visible spot at the display surface, means for causing said spot to scan over said display surface in a rectangular raster scan pattern made up of a plurality of substantially rectilinear scan lines extending substantially parallel to one another in a predetermined direction, and means for varying the intensity of the spot, said apparatus comprising:

• first means for forming an output signal representing the instantaneous difference between the voltage of the waveform and a voltage representing the position, in the raster scan pattern, of the scan line then being executed;
• second means for receiving an input signal and producing, as an output signal, a clipped version thereof;
• third means for receiving an input signal having voltage levels which are positive and negative with respect to a predetermined reference level and generating an output signal representing the absolute value thereof with respect to said reference level;
• fourth means for receiving an input signal and producing, as an output signal, the inverse thereof;
• fifth means for receiving an input signal including excursions from a given voltage level and producing an output signal in which the given voltage level is shiftable to a predetermined voltage level;
• and
• sixth means for receiving an input signal including excursions of a given amplitude and producing an output signal in which the excursions are adjustable to a predetermined amplitude;
• said second, third, fourth, fifth and sixth means being connected together so that the input signal received by one such means is the output signal provided by another such means, and being connected to the first means so that the output signal of the first means is the input signal of one of the second to sixth means.