Abstract: A display test system includes a symbol source and a controller connected to the symbol source for receiving a symbol in response to a testing event whereupon the controller causes the display to produce a first area having a first light intensity, and the symbol at a second light intensity within the first area. A viewer uses an input device to verify to the controller the ability to discern the difference in light intensities of the symbol and the first area by describing or identifying the symbol.

Abstract: A display test system includes a symbol source and a controller connected to the symbol source for receiving a symbol in response to a testing event whereupon the controller causes the display to produce a first area having a first light intensity, and the symbol at a second light intensity within the first area. A viewer uses an input device to verify to the controller the ability to discern the difference in light intensities of the symbol and the first area by describing or identifying the symbol.

Abstract: A method and apparatus for evaluating the degradation of a video display device. Single parameter test signals and patterns, generated either internally or externally to the video device, are displayed on the screen. A sensing device such as a CCD camera reads the screen and transmits the data to a processing unit. Codes, imbedded in the test signal or pattern, indicate to the testing device what test is currently being run, the content of the test, and/or the specific setup situation. The code may be inherent in the pattern, the sequencing, or in addition thereto. The processing unit reads and interprets the results in accordance with the received test codes. The apparatus includes a portable, hand-held unit capable of detecting video degradation on a pass/fail basis. The unit is separate from the display under test and is capable of identifying and evaluating the test through the receipt and interpretation of the embedded codes in the test patterns, and evaluating performance on a go/no-go basis.

Abstract: A method and apparatus for evaluating the degradation of a video display device. Single parameter test signals and patterns, generated either internally or externally to the video device, are displayed on the screen. A sensing device such as a CCD camera reads the screen and transmits the data to a processing unit. Codes, imbedded in the test signal or pattern, indicate to the testing device what test is currently being run, the content of the test, and/or the specific setup situation. The code may be inherent in the pattern, the sequencing, or in addition thereto. The processing unit reads and interprets the results in accordance with the received test codes. The apparatus includes a portable, hand-held unit capable of detecting video degradation on a pass/fail basis. The unit is separate from the display under test and is capable of identifying and evaluating the test through the receipt and interpretation of the embedded codes in the test patterns, and evaluating performance on a go/no-go basis.

Abstract: A control system for controlling a heating system having a heat pump and a source of supplemental heat. The indoor heat exchanger temperature is monitored, such as by a thermocouple or the like, and when the temperature falls below a given threshold level, defrost cycling of the heat pump is initiated. The control system monitors the defrost cycling of the heat pump, and when the heat pump is in its defrost cycle for more than a predetermined portion of a heating cycle, the heat pump will be shut down until the outdoor ambient temperature has risen by a predetermined amount or a given interval of time has elapsed.

Abstract: A television video pattern generator system comprises a keyboard for entering pulse width and timing parameters for a video scanning rate. The individual incremental pulse width and timing parameters for the horizontal and vertical synchronizing waveforms are entered into a keyboard. A pattern selector selects a particular pattern which the operator wants to display on the video screen. The entered values are stored in a memory and a central processing unit processes the entered parameters and causes horizontal and vertical generators to generate the horizontal and vertical scan signals. A sync generator receives inputs from the horizontal and vertical generators and generates the scan rate. A pattern generator receives inputs from the sync generator and a pattern selector and generates a video display pattern in accordance with the selected pattern parameters and the selected scan rate parameters.

Abstract: A control system for controlling a heating system having a heat pump and a source of supplemental heat. Simultaneous operation of the heat pump and supplemental heat source is monitored, and when such simultaneous operation occurs for a given portion of a heating cycle, the heat pump will shutdown until the temperature has risen by a predetermined amount or a given interval of time has elapsed. The heat pump is also shutdown if the outside ambient temperature falls below a certain level and is automatically reenabled if the outside ambient exceeds a second level.

Abstract: A control system for controlling a heating system having a heat pump and a source of supplemental heat. The control system monitors the defrost cycling of the heat pump, and when the heat pump is in its defrost cycle for more than a predetermined portion of a heating cycle, the heat pump will be shut down until the outdoor ambient temperature has risen by a predetermined amount or a given interval of time has elapsed. The heat pump is also shut down if the outside ambient temperature falls below a certain level and is automatically reenabled is the outside ambient exceeds a second level. The system results in more efficient operation of the heat pump/supplemental heat system by disabling the heat pump when weather conditions do not favor efficient heat pump operation.

Abstract: A method and apparatus for measuring the Gray Scale characteristics of a CRT display wherein a luminance meter surveys a ten percent portion of the total surface area of the screen of the CRT display screen. The luminance meter is positioned far enough from the screen so that the cone surveyed by the luminance meter will intersect the plane of the screen to cause ten percent of the screen surface area to be surveyed. A special test pattern is generated for display on the CRT screen whereby a surveyed area is provided having a sufficiently large surface area and being of uniform brightness. The test pattern also provides for an additional screen area equal in size to the surveyed area. The average picture level for the surveyed area and the non-surveyed area is maintained at fifty percent of peak picture level while the brightness of the surveyed area is varied in incremental steps through the Gray Scale.

Abstract: A pulse stretching circuit for a raster display for causing certain vertical control pulses to either have the same widths or at least terminate at the same time in both the odd and even fields. The vertical blanking pulses or vertical sync pulses in the odd fields are stretched so that they terminate coincident with the trailing edges of the 2H rate horizontal blanking or sync pulses respectively.

Abstract: A method and apparatus for testing the geometry of a cathode ray tube raster scan under beam duty cycle variation. Alternate polarities of white on black and black on white images of a test pattern are displayed on the CRT screen, and the displacement of a reference point from one polarity to the other is measured to determine quantitatively the amount of displacement. Preferably, the pattern comprises a plurality of regularly arranged and spaced graphic elements, such as a bar, dot or dot grating pattern, wherein the pattern occupies a low percentage of the screen area. By alternately switching the polarity, the electron beam of the CRT undergoes wide swings in the amount of current it draws from the high voltage supply, and the amount of image displacement and size deviation can be readily measured.

Abstract: The method for testing the linearity and other raster scan geometry of a television display apparatus or a television camera. The method is used when the display apparatus or camera being tested has a scan rate which cannot match the currently used EIA linearity chart due to fundamental differences in the raster structure and can also be used on the 525/60 scan rate as used in broadcast mode without requiring the unusual alternate count required for the EIA chart. In testing a display apparatus, a bar or dot pattern is formed on the screen by a test pattern generator wherein the spacing of the horizontal rows of dots or bars is selected to correspond to a particular scan rate. A linearity chart having a geometry corresponding to that scan rate is selected from a plurality of test charts and the image thereof is projected on the screen to match, as closely as possible, the dots or bar intersections on the screen.

Abstract: A selectable rate sync generator system for use with a television test pattern generator includes a master oscillator of predetermined frequency, selector switches for selecting the desired total horizontal line time, and a horizontal line trigger circuit for generating a train of clock pulses having twice the repetition rate (2H) of the line time selected. H rate blanking and drive pulses are generated in response to the clock pulses. Selector switches are provided for selecting a desired number of horizontal scanning lines in two fields, and a vertical trigger circuit generates vertical trigger pulses having the repetition rate (V) of the number of lines selected. V rate blanking and drive pulses are generated in a response to the V trigger pulses, and the H and V rate blanking pulses are summed to provide a composite blanking signal. H rate sync pulses are generated in a response to the clock pulses and are delayed therefrom by a predetermined interval.

Abstract: The application relates to an interlace detector for a raster beam control circuit, such as in a television or computer display. Under 1:1 interlace conditions, depending on the condition of the logic at the time that the 1:1 interlace is selected, an odd field condition may result wherein the first half of the top horizontal line and the second half of the bottom horizontal line are blanked. The interlace detector detects this situation by detecting coincidence between a horizontal blanking pulse and the vertical reset pulse, and delays the transmission of the vertical reset pulse to the vertical field counter for one-half of the horizontal line scan time. This, in turn, delays vertical blanking so that a full line of information appears in the upper and lower lines of the display. In the specific embodiment disclosed, a bistable circuit triggered by horizontal blanking pulses and the undelayed vertical reset pulse produces the delayed vertical reset pulse.

Abstract: A selectable rate sync generator system for use with a television test pattern generator includes a master oscillator of predetermined frequency, selector switches for selecting the desired total horizontal line time, and a horizontal line trigger circuit for generating a train of clock pulses having twice the repetition rate (2H) of the line time selected. H rate blanking and drive pulses are generated in response to the clock pulses. Selector switches are provided for selecting a desired number of horizontal scanning lines in two fields, and a vertical trigger circuit generates vertical trigger pulses having the repetition rate (V) of the number of lines selected. V rate blanking and drive pulses are generated in a response to the V trigger pulses, and the H and V rate blanking pulses are summed to provide a composite blanking signal. H rate sync pulses are generated in a response to the clock pulses and are delayed therefrom by a predetermined interval.

Abstract: An electronic switch in which first, second and third transistors are arranged in a group and provide for switching signals from a supply thereof to a signal buss. The source of signals is supplied to the base of the first transistor and from the emitter thereof to the base of the third transistor. The emitter of the third transistor is connected to the signal buss. The second transistor is connected between the signal path leading from the emitter of the first transistor to the base of the third transistor to ground and is controlled as to conductivity by the selective supply of voltage signals to the base thereof. The signal path from the source of signals to the signal buss is characterized in extremely low impedance when the switch is `ON` and in extremely high impedance when the switch is `OFF`, with the switch operating between on and off conditions extremely rapidly.

Abstract: A start-stop oscillator circuit in which the oscillator circuit includes an inductor connected in parallel with a pair of serially connected capacitors. The inductor and capacitors form the tank circuit for the oscillator which is in the form of a Colpitts oscillator. In order to start and stop the oscillator within a brief period, not to exceed the conventional blanking interval for a television, switches are connected between one end of the inductor and ground and from a point between the capacitors to ground. The end of the inductor opposite the end to which the switch is connected and the corresponding end of the capacitor branch are also connected to ground.

Abstract: A power loss alarm system in which an electric power supply is connected to a relay so that the relay is energized while the power supply is on. If the power supply fails, or if the voltage is reduced below a certain minimum amount, the relay is de-energized and an alarm signal is activated. The alarm signal is connected to second source of electric power, a battery, for example, so that power loss in the power circuit will not prevent actuation of the alarm. The system includes a selector switch having an "OFF" position, an "ON" or "RETURN" position in which the system is checked and is also operative to sound the alarm when power returns to the system, and a "LOSS" position in which the system is operative to indicate the occurrence of loss of power.