Abstract: An analog-to-digital converter latching circuit functions alternatively in a degenerative mode and a regenerative mode. During degeneration, circuit stray capacitances are substantially discharged for resulting in fast operation. When the circuit switches from degeneration to regeneration, a small signal current is able to start the latch in the proper direction without first having to overcome charge stored in the stray capacitances.

Abstract: A dual output balun distributes substantially all of the available power in a single ended input signal applied thereto (less small parasitic losses) equally to two or more pairs of push-pull output terminals (or vice versa).

Abstract: A transmission line transformer that can balance imperfectly balanced signals, and can convert a balanced input to an unbalanced output. The transformer includes two unbalanced transmission lines each having a characteristic impedance Z.sub.o. The outer conductor of each is interrupted at its midpoint and is connected to the corresponding interrupted outer conductor of the other. An input signal applied across the ends of the first line's center conductor yields a balanced outer signal across the ends of the second line's center conductor. An unbalanced output can be obtained by terminating one end of the second line with an impedance Z.sub.o.

Abstract: A single-ended to differential coupling device includes an input coaxial transmission line feeding sections of output coaxial transmission line across a break or gap between the outer conductors of the output transmission lines. A shunt resistor across the input transmission line and a series resistor interposed between the center conductors of the output transmission lines provide exact impedance matching in conjunction with plural ferrite toroids disposed about at least one of the transmission lines to prevent shorting of the input signal.

Abstract: An acoustic detection method and apparatus includes a source of high voltage pulses to be applied to an underground cable suspected of having a ground fault. As the pulses encounter the fault, acoustic energy is generated which may be sensed by a pair of transducers located along the path of the cable. The transducers are connected to signal processing circuitry which provides a display signal indicating which of the two transducers lies closer to the fault. The transducers are moved along the path of the cable in the direction indicated and the test is repeated until the fault is indicated as lying in the opposite direction. Thereafter the transducer are moved in the opposite direction in a shorter increment. This procedure is repeated until the direction to the fault changes each time the transducers are moved. The fault then lies midway between the midpoints of each of the two final transducer positions.

Abstract: A fault is located in an insulated electrical conductor buried in earth by establishing a voltage gradient through the earth emanating from the fault, and thereafter sensing the direction of the gradient to locate the fault. The voltage gradient is established by applying a pulsed voltage initially to the conductor at a voltage level significantly less than the maximum voltage level of which the voltage source is capable. The presence or absence of a voltage gradient as a result of such initial voltage level is sensed and, if no gradient has been established, the voltage level is increased somewhat and reapplied, but at a level still significantly less than the maximum level of which the voltage source is capable. After the voltage gradient has been established, the voltage level varies within a range no higher than the initial voltage level at which the gradient was established, so as to maintain the voltage gradient.

Abstract: A method for analyzing stored image details for identification purposes is disclosed in which slopes are abstracted from an image to provide three-dimensional recognition information as abstractions. Data representing light levels of an image are stored in a picture memory device, which is analyzed in a predetermined manner to select absolute illumination magnitudes between fixed locations of the image. This information is directly related to the slope between the locations. Steeper slopes and their corresponding locations are stored as recognition data in a learn mode. These abstractions are compared and several are permanently stored. In an access mode, the previously-obtained information is utilized to verify with current data, and depending upon the degree of correlation therebetween, an indication of recognition is either verified or rejected.

Abstract: A method for analyzing stored image details for identification purposes is disclosed in which slopes are abstracted from an image to provide three-dimensional recognition information. Data representing light levels of an image are stored in a picture memory device, which is analyzed in a predetermined manner to select absolute illumination magnitudes between fixed locations of the image. This information is directly related to the slope between the locations. Steeper slopes and their corresponding locations are stored as recognition data in a learn mode. In an access mode, the previously-obtained information is utilized to locate new data, and depending upon the degree of correlation therebetween, an indication of recognition is either verified or rejected.

Abstract: A battery powerable electrical signaling apparatus for assisting in locating a concealed electrically conductive element, such as an underground pipe. Provided in the apparatus is circuitry which functions automatically to change the output impedance of the apparatus, when such is coupled electrically to a pipe or like element, so as to match as closely as posible, the apparatus' output impedance with that of the hidden element. Thus, the proposed circuit conserves limited energy of a battery, and extends service life.

Abstract: An identification system includes means for scanning an identity pattern in a predetermined manner and correlating previously-obtained recognition data with information derived therefrom to determine a positive identification. In obtaining recognition data, the identity pattern is scanned and digitized in a predetermined manner, and then analyzed and sorted to provide prominent information most likely to be recognized in subsequent identity verifications with the original recognition pattern. In this manner, unique recognition data for each identity pattern is stored and is available for rapid retrieval and correlation when the original identity pattern is presented.

Abstract: Scaling apparatus for measuring the dimensions of an article, such as a log, including a two-dimensionally curved parabolic mirror for viewing an article, and a constant-speed, rotary, electro-optical scanner located at the focal point of the mirror for scanning the mirror's view. Electrical pulse-generating circuitry in the apparatus operates during such scanning to generate, for each revolution of the scanner, a stored pulse count which directly indicates the side-to-side dimensions of a viewed article. Included in such circuitry is means for varying, in effect, the rate at which pulses are counted so as to correct the finally stored count for nonlinearity inherently encountered in the scanned view of the mirror.