Abstract: A pressure transducer comprises two similar resonantly vibratable cylinders, one disposed coaxially inside the other and each having its own resonant vibration excitation system. A pressure P1 is applied to the inside of the inner cylinder and to the outside of the outer cylinder, while a pressure P2 is applied between the cylinders, whereby the difference in the respective vibration frequencies of the cylinders is dependent on the pressure difference P1-P2. Either P1 or P2 can be a reference pressure, e.g., a vacuum for an absolute pressure version of the transducer. Alternatively, either P1 or P2 can be atmospheric pressure, so that the transducer operates as a gauge pressure transducer.

Abstract: A control meter is disclosed having a structural arrangement readily adaptable for usage as either a potentiometric or photoelectric type of instrument. Commonality of parts for the two types is maximized and only a few additions are required to operably complete the structure of either type.

Abstract: An on-screen television display including means internally of the receiver for generating characters to indicate the channel number, time of day or other data. The system includes circuit means responsive to the horizontal and vertical sync signals of a television receiver for positioning and timing of the display. BCD data is coupled to a character generator, and the output of the character generator is then multiplexed with positioning and timing signals. The multiplexed output is coupled to a video interface which supplies the video signal to the cathode ray tube.

Abstract: Apparatus for testing, cleaning, and rejuvenating three gun, color television, cathode ray picture tubes is disclosed. The apparatus shown permits the cleaning and rejuvenating procedures to be performed separately and on selected, individual ones of the cathode ray tube guns so that these procedures need be carried out only on those guns actually requiring them. The apparatus includes a great deal of flexibility and, in particular, its full capabilities may be used even with cathode ray tubes having the control grids of the separate guns connected together in parallel.

Abstract: A time delay switch is disclosed for permitting a load to be powered over a preselected period of time. The switch automatically cuts off power to the load when the period expires. The disclosed switch draws no power in its "Power Cut-Off" state thereby conserving the life of the power source. In addition to being power conservative the disclosed switch features rapid power turn on, emergency power cut off and is capable of being operative in its "Power On" state over relatively long periods of time.

Abstract: The analogue storage circuit comprises a nonlinear amplifier for amplifying an input voltage. The amplifier includes means for generating a sequence of predetermined voltages, each predetermined voltage being higher than the preceding one in the sequence. A plurality of voltage level responsive circuits are each connected to receive the input signal and a respective one of said predetermined voltages and are each arranged to change from a first state to a second state as the input voltage passes through a level of equality with the respective predetermined voltage in a given direction. An output circuit is provided, as well as a plurality of voltage follower circuits each having a first input connected to receive a respective one of the predetermined voltages and an output connected to the input of the output circuit.

Abstract: A frequency counter is disclosed which determines the frequency of an input signal in a high speed and accurate manner. High speed is achieved by utilizing electronic digital processing circuitry. The high degree of accuracy is achieved by a combination of elements which perform period averaging of an integral number of periods of the input signal over a flexible measurement interval. The counter is particularly useful in accurately measuring low frequency signals.

Abstract: A highly linear AC to DC conversion system comprises a variable gain amplifier via which an AC signal to be converted is applied to an AC/DC converter. The output of the AC/DC converter is compared with a reference level and a control signal dependent on the difference therebetween adjusts the gain of the variable gain amplifier so as to reduce the difference. The output of the AC/DC converter is also applied to one input of a comparator, whose DC output is applied via the variable gain amplifier to the other input of the comparator. The variable gain amplifier has exactly the same gain for both AC and DC signals. It can then be shown that the DC output signal produced by the comparator is very accurately linearly related to the magnitude of the AC input signal.

Abstract: A fully digital spectrum analyzer accepting as an input either an analog signal or a series of digital numbers and using time compression and DFT (Discrete Fourier Transform) techniques to provide the spectral component values of the input signal. Novel techniques and means are used in obtaining the power values for selected spectral lines and in averaging these power values. Statistically controlled noise is added to the input of the spectrum analyzer to enhance its resolution beyond the resolution which would be otherwise available. Advanced and efficient techniques are used for generating and applying trigonometric functions in the course of finding the real and imaginary part of Fourier transforms, and for providing running averages of the power spectra.

Abstract: A dual slope analog-to-digital converter, which has an autozeroing circuit for cancelling out integrator and detector offset and drift, is additionally provided with a circuit for injecting a voltage of selected polarity and magnitude to offset the input voltage of the converter such that the input voltage can be measured with respect to a nonzero reference line.