Abstract: A capability for internal self-testing is provided for a test instrument in which data, in digital and in analog form, is sampled from various test points. A programmable delay generator is used to process some of the data and to provide strobes which control the data output and which control the sampling of data. This enables measurements to be made at a preselected time after the occurrence of a particular signal, thereby giving the system a capability of using the delay generator not only for providing comparisons of time functions but also for initiating test sub-routines.The self-test capability enables test equipment having time-dependent functions, such as test equipment for video displays, to be verified with respect to accuracy in order to establish a confidence test.

Abstract: A front for test patterns is made programmable by programming individual "characters" to be displayed on a video display. The individual characters are assigned memory locations and can be adjusted in height and width, as well as in color and intensity. Complex characters are formed by programming additional features onto a character memory space assigned to each character. The system provides a greater ratio of pattern generating capability-to-required hardware, while providing most features of a fixed character generator. The system's programmability is particularly adapted to use with a test system which has capabilities of incrementally varying scan rate and raster patterns, as well as a capability of random stroke and fixed mode stimuli generation.

Abstract: A Digital Automatic Gain Control for a display system having a video display driven by a remote display generator including a display processor which generates binary words that are converted by multiplying digital-to-analog converters to analog deflection voltages that are applied to the video display. The deflection voltages applied to the display are sensed and a digital feedback signal is derived therefrom that is returned to the display generator. The digital feedback signal has a word size larger than the word size of the binary words generated by the display processor. The feedback signal is processed and applied to multiplying digital-to-analog converters and output amplifiers to modify the conversion from binary words to analog deflection voltages to thereby accomplish higher display resolution and accuracy than can be achieved by the display processor alone due to limited binary word size.

Abstract: A video test pattern generator is able to be incrementally adjusted in its number of lines and in its line resolution, and at the same time is able to produce a reference frequency. The reference frequency is established at a selected value and offset from the selected value by an amount necessary to coincide with a multiple of a scan line frequency. This can be accomplished despite changes in scan rate and raster pattern. A stroke generation capability is provided and the system can be utilized with programmable character generation and can produce a high-resolution image with a minimum of hardware. Further advantages include the ability of the system to adapt to new or changed equipment to be tested.

Abstract: A display analyzer analyzes an image from a unit (10) under test. The analyzer has a carriage (18, 20) for adjustably supporting a detection device (16). The carriage has at least two degrees of freedom. The detection device has a given field of view and can produce a viewing signal responsive to the image size and brightness within the field of view. This viewing signal is produced with a predetermined characteristic in response to the appearance of a given image at the center of said field of view. The display analyzer also has an analyzing device (50) for producing a carriage adjustment signal. The carriage is operable to move in response to this adjustment signal. The analyzing device is operable to produce information in response to the production of the viewing signal.