Abstract: A filter utilizing charge transfer devices and having resonant transfer characteristics is described. The filter includes a first charge transfer shift register including a plurality of stages to which a first sequence of packets of charge is serially applied and clocked from stage to stage. Charge division and collection means are provided at the various stages of the shift register to divide and collect fractions of charge appearing in the various stages thereof. The charge collection means of the various stages except the last are connected together to provide a first output representing the sum of the charges collected at the various stages thereof. These fractions represent the weighting coefficients of the various stages of the first shift register. A second charge transfer shift register identical to the first shift register is provided. A second sequence of packets of charge is serially applied to the second shift register and clocked from stage to stage.

Abstract: The input data format in a single-sector or multi-sector scanner imaging system is chosen such that angulated scan lines intersect a lateral line at equal increments, and along the scan lines the echo signal is sampled at different rates whereby sampling points are along parallel raster lines. Successive scan lines are stored in adjacent columns of a row-column oriented digital memory. Echo data is read out of memory row by row at a variable rate to convert the read-out data back to sector geometry. The image is displayed in real time in a cathode ray tube.

Abstract: A conductor-insulator-semiconductor (CIS) structure for a random access surface charge memory system is disclosed. The memory system comprises an array of memory cells including charge storage regions, charge transfer regions and charge receive-source regions formed along the surface-adjacent portions of a semiconductor substrate. A charge-storage line insulatingly overlies the storage regions of a row of memory cells and a bit line, comprising an extended region of opposite-conductivity-type, interconnects the receive-source regions of the same memory cells. Addressing in the Y-direction (word selection) is provided by charge transfer lines insulatingly overlying the charge transfer regions of a column of memory cells. Selected memory cells are addressed for read and write purposes by first activating the word select line which makes available one cell in each row of the memory. The desired row is then selected by means external to the array of memory cells.

Abstract: A curved transducer array or a flat array with an acoustic converging lens functions as a fixed focus physical lens and is focused near maximum range. At longer ranges the full aperture is utilized for good resolution, and at shorter ranges up to a specified fraction of maximum range improved resolution is achieved by a dynamic aperture control which increases the array aperture by steps by switching in more transducer elements. This simplified sector scanner does not require dynamic electronic focusing.

Abstract: A linear transducer array with low overall side lobe sensitivity for use in steered beam imagers has a different interelement spacing for transmit than for receive, and preferably has a shorter transmit array with elements spaced at one-half wavelength as the center portion of a longer receive array whose unit elements are spaced at a full wavelength. Two or more elements in the center portion can be coupled together to a receiving channel to maintain constant spacing for the receive aperture in a 100% active transducer.

Abstract: A charge-coupled device (CCD) multiplying digital-to-analog converter mullies a bipolar analog signal, representing as a charge, by a digital word, and produces a four-quadrant analog product, also represented as a charge. An analog signal S is added to or subtracted from a bias, resulting in signals S+B and -S+B, which are converted into corresponding positive charges, Q.sub.S +Q.sub.B and -Q.sub.S +Q.sub.B, which are transferred into potential wells at X.sub.i and Y.sub.i, respectively. A digital word may be represented as b.sub.1 b.sub.2 b.sub.3 . . .b.sub.N, where N is the word length. The CCD converter comprises N parallel devices, each of which performs the function of multiplying the signal S by either 0 or 1/2.sup.i. A gate between X.sub.i and Y.sub.i is controlled by the binary bit b.sub.i. Equilibration occurs or does not occur depending on whether b.sub.i equals 0= or 1. The charges left in X.sub.i and Y.sub.

Abstract: A real time ultrasound imaging system which includes coherent demodulation of echo signals followed by time delay and coherent summation of the demodulated signals is described. As the range from which echoes are being received increases, coherent demodulation is maintained. Demodulation and time delay accuracies are relatively easy to maintain over a large field of view and a long range. The system has high resolution and high sensitivity.

Abstract: A real time ultrasound imaging system provided with a fixed focus and including coherent demodulation of echo signals followed by time delay and coherent summation of the demodulated signals is described. As the range from which echoes are being received increases, coherent demodulation is maintained. Demodulation and time delay accuracies are relatively easy to maintain over a large field of view and a long range. The system has high resolution and high sensitivity.

Abstract: A B-scan ultrasonic imager produces a rectilinear image and has a linear transducer array with only one switch per element. Individual elements or overlapping transmit subarrays are selected sequentially to generate pulses of ultra-sound. Received echo signals are sequentially sent down a long shift register delay line, are tapped off at the pulse repetition rate, and delayed by different amounts in the several channels and summed to effect time delay focusing of the echoes. The video output signal is post-processed to improve the TV monitor picture; interpolated image lines are conveniently derived with this architecture.

Abstract: A charge transfer filter includes an accumulator charge storage location and means for alternately introducing charge into the accumulator charge storage location and then for removing a preselected fraction of the total charge in the accumulator charge storage location so that the total accumulated charge is known.

Abstract: Geometries suitable for split or paired electrode structures of small effective dimensions which are readily implementable with a high degree of accuracy are provided.

Abstract: Methods for storing and transferring electrical charges between adjacently spaced storage regions in semiconductor substrate are disclosed. In one embodiment, a plurality of adjacently spaced conductor members are insulatingly disposed over a major surface of a semiconductor substrate. Each storage region is separated from each other storage region by an electrical barrier region underlying the spacing between the adjacent conductor members. These barrier regions are controllably lowered by an electrode interposed between adjacent conductor members. Electrical charges stored in one storage region are transferred to an adjacent storage region by applying a voltage signal to the interposed electrode to lower the barrier region between the adjacent storage regions. Direction of charge transfer is controlled by the relative surface potentials of the adjacent storage regions and the magnitude of transfer is controlled by the height of the barrier region when lowered.

Abstract: The output circuit includes a high gain differential amplifier having an inverting input terminal, a non-inverting input terminal and an output terminal with a feedback capacitance connected between the output terminal and the inverting input terminal. The input terminals are connected to first and second commonly phased lines of the charge transfer transversal filter. First and second charging and isolating means are connected between a source of operating voltage and the first and second commonly phased lines, respectively. The lines are charged periodically to the voltage of the source by the first and second charging and isolating means prior to the transfer of charge in a cycle of operation of the filter and are then isolated from the source during the transfer of charge in the filter by the first and second charging and isolating means.

Abstract: Apparatus and methods for regenerating electrical charges to predetermined levels are disclosed. In one embodiment, electrical charges are regenerated in response to a changed voltage condition on an electrically isolated diffused region adapted to receive such charges. The regenerated charges are of predetermined magnitudes substantially independent of the magnitude of the received charge except for whether or not the received charges are above or below a threshold value. Means for regenerating a level of charge substantially less than 100 per cent of a normalized charge are also disclosed.

Abstract: In a charge transfer device electrode operating voltage is applied through a high-gain differential amplifier having an inverting and a non-inverting input terminal with capacitive feedback from the output terminal to the inverting terminal. The inverting terminal is connected to the charge transfer device electrode. The non-inverting terminal is connected to a source of operating voltage. During the transfer of charge the voltage on the electrode is maintained substantially constant and a voltage change is produced at the output of the amplifier which is approximately equal to the induced charge divided by the feedback capacitance.