Abstract: A method and an apparatus detect the presence of and correct for timing misalignment between waveforms acquired by digital oscilloscopes. In a preferred embodiment, a digital oscilloscope (50) includes a waveform alignment system (60) that receives a first waveform (86) and a similar second waveform (88) of a periodic electrical signal. A digital signal processor (80) of the waveform alignment system generates an autocorrelation value in connection with the first waveform and a first cross-correlation value in connection with the first and second waveforms and compares the values to determine whether they differ by more than a preselected tolerance, thereby to detect a timing misalignment between the first and second waveforms.

Abstract: A bipolar-CMOS (Bi-CMOS) digital interface circuit (50) of the present invention provides an interface between a bipolar digital circuit (52) and a CMOS digital circuit (54). The digital interface circuit includes a digital transform circuit (56) that receives a bipolar logic signal generated by the bipolar digital circuit and transforms the signal into an intermediate logic signal whose voltage waveform is positioned symmetrically about a logic threshold generated by a CMOS digital input circuit (58). The CMOS digital input circuit receives the intermediate logic signal and generates a CMOS logic signal that is delivered to the CMOS digital circuit, thereby to interface the CMOS digital circuit with the bipolar digital circuit.

Abstract: A graphics display system (10) includes a display screen (14) on which images are formed and a data transform circuit (12) that provides transformations between model data representing the basic shape of an object and display data that are employed in the formation of an image of the object on the display screen. The model data are transformed into display data in accordance with position data and orientation data that correspond, respectively, to a translation and a rotation of the image on the display screen. The data transform circuit communicates with a central processing unit (30) that controls the operation of the graphics display system. The data transform circuit includes data storage registers (34, 36, 38, 40, 42, 44, 46) that receive and hold the model, position, and orientation data. A multiplier circuit (68) and an adder circuit (112) calculate the transformation of the model data into display data.

Abstract: An acceleration and scan expansion lens system for use in an electron discharge tube provides scan expanion in which the amount of scan expansion provided in the horizontal direction is independent of the amount of scan expansion provided in the vertical direction. In a preferred embodiment, the lens system (10) is employed in a cathode-ray tube (12) which has greater deflection sensitivity in the vertical direction than in the horizontal direction. The lens system includes a mesh electrode structure (62) that has a dome-shaped mesh element (66) which is supported by an electrically connected to a metallic cylindrical support element (70). The dome-shaped mesh element is formed to have a concave surface as viewed in the propagation direction (35) of the electron beam and is of rotationally symmetric shape. The lens system also includes an annular electrode element (64) that has an aperture of elliptical shape and is positioned adjacent the output end of the mesh electrode structure.