Abstract: A serial access memory includes a pair of bit lines, a plurality of memory cells each coupled to one of the bit lines and a pair of data lines. The serial access memory also includes a sense amplifier drive line, a sense amplifier, data latch circuit, data transfer circuit and a drive capability control circuit. The sense amplifier drive line is coupled to a potential source for supplying a sense amplifier drive signal from the potential source. The sense amplifier is coupled to the bit lines and the sense amplifier drive line for amplifying a difference of electrical potentials appeared on the bit lines in response to the sense amplifier drive signal. The data latch circuit is coupled to the bit lines and the data lines for latching the amplified electrical potentials appeared on the bit lines as data. The data transfer circuit is coupled between the bit lines and the data latch circuit for controlling an electrical connection between the bit lines and the data latch circuit.

Abstract: A method and apparatus are disclosed for filtering ghost signals from a video signal sequence. Storage circuitry stores a representation of a reference signal, Input circuitry inputs video signals from the video signal sequence. Comparison circuitry compares the stored representation of the reference signal with a reference signal received in the video signal sequence at the input circuitry, thereby to detect ghosts. Filter coefficient generating circuitry is connected to the comparison circuitry to generate a frequency domain representation of filter coefficients dependent on ghost signals detected. A forward Fourier transform pipeline is connected to the input circuitry to form a frequency domain representation of data in the video signal sequence received by the input circuitry. Product forming circuitry forms in the frequency domain a product of the filter coefficients with the frequency domain representation of the data in the video signal sequence.

Abstract: A track and hold system for use with a test instrument such as a multimeter includes an input circuit, a buffer amplifier, a storage device such as a capacitor, an output amplifier, an output circuit, a detector for detecting a pulse on a signal passing from the input to the output, and a switch responsive to the detector for isolating the storage device from the input circuit but not the output circuit for a predetermined period. The system also includes a timer responsive to the detector to provide an isolation command to the switch for the predetermined period. Further, the system includes a delay circuit, responsive to the detector, for interposing a delay of variable duration prior to activating the timer.

Abstract: An interface circuit for use in a data transmission system has a first port for connection to a 16 wire data highway of the type proposed by the I.E.C. (International Electrochemical Commission) for the interconnection of instruments, and a second port capable of being connected to an eight-wire or two-wire data link. The interface circuit includes an encoding circuit operative to encode at least some commands applied to the first port, and an enabling circuit for selectively enabling data applied to the data terminals of the first port and the encoded commands to pass to the second port.

Abstract: A position indicator is disclosed which includes the combination of a linear voltage differential transformer (LVDT) and accuracy assurance circuitry. The LVDT includes a movable core connected to a mechanism whose position is to be indicated. The accuracy assurance circuitry permits the disclosed indicator to operate substantially independent of fluctuations in input voltage or frequency. This substantial independence is achieved in the following manner. First, the voltage across the LVDT is rectified by a first precision rectifier. Simultaneously, the LVDT tap voltage is rectified by a second precision rectifier. Each precision rectifier output is filtered and then applied to an analog divider which "cancels out" the effects of input voltage or frequency fluctuation. The divider output is an analog signal which is a true ratio of tap voltage to voltage across the LVDT. This true ratio signal accurately represents the position of the mechanism connected to the movable core.

Abstract: A printed circuit mother board, for interconnecting the respective edge connectors of a plurality of other printed circuit boards having digital circuitry thereon, has a set of generally straight, approximately parallel tracks on each side. Each set of tracks comprises alternate signal tracks and ground tracks, and the ground tracks of each set are interconnected with each other to approximate to a ground plane. Additionally, the tracks on one side of the board are slightly laterally displaced with respect to the tracks on the other side, so that each signal track on either side is opposite a ground track on the other side. The possibility of interference between signals carried by the signal tracks is thus reduced, and the board has transmission line characteristics.

Abstract: A partial response QAM Modem is provided wherein a transmit signal is generated by modulating band limited, multilevel, partial response precoded data with inphase and quadrature carriers in inphase and quadrature phase channels, respectively, and summing the modulated outputs. The received signal is processed by a passband automatic complex equalizer. The equalized signal is delayed and then demodulated with recovered inphase and quadrature carriers to recover the inphase and quadrature phase baseband signals. The recovered baseband signals are sampled at appropriate instants to produce estimates of the transmitted symbols. These symbols are partial response decoded and processed by error correctors to improve the overall system performance. The error corrector outputs are decoded to convert the multilevel estimated data to binary data and the binary data of the two channels is summed to obtain estimates of the binary data transmitted.

Abstract: An uninsulated contact array of resilient electrically conducting metal with bridging strips at each end to hold multiple conductors in predetermined spaced relation to each other. The bridging strips permit terminal tips at one end of the conductors to be stabbed into a circuit board simultaneously, for subsequent soldering. The other ends of the conductors, having contact ends, are maintained in spaced apart relation by a second bridging strip, the conductors and contacts permitting threading the contact ends simultaneously into multiple recesses of a display holder socket. The display holder socket is so arranged, that curving the resilient conductors increases the contact pressure of the contacts by bowing them. Resilient mounting arms of the contact holder provide for shock proof mounting of the contact holder in a casing by clamping the resilient arms between the casing and cover of an instrument housing.

Abstract: A digital voltmeter for measuring an input voltage which can lie in any one of M successive ranges comprises an input scaling device which scales the input voltage to produce a voltage lying in a single predetermined range, and which also produces a range signal indicative of the range in which the input voltage lies. An analogue-to-digital conversion circuit then converts the scaled voltage to a corresponding digital signal which has up to N significant decade figures of resolution, where N<M. The voltmeter has a display unit with M decades, each of which represents a fixed order of magnitude of the input voltage, and control means responsive to the range signal to direct the digital signal to the group of N adjacent decades of the display means appropriate to the magnitude of the input voltage.

Abstract: A displacement transducer comprises a charge coupled device having a plurality of light sensitive stages arranged in a line. An obturating member connected to a member whose displacement is to be transduced is disposed between the charge coupled device and a light source. As the obturating member is moved, it varies the amount of light received by the respective stages of the charge coupled device, so that the charge distribution in the charge coupled device is representative of the position of the obturating member and therefore of the member whose displacement is to be transduced.

Abstract: A correction circuit for correcting the frequency of the output pulses produced by a gas flowmeter in dependence on the temperature of the gas comprises a control input for receiving a voltage representative of the difference between the temperature of the gas and a reference temperature. A voltage-controlled oscillator, operative during fixed short periods initiated by each flowmeter pulse, produces auxiliary pulses at a rate dependent on the voltage at the control input, and the auxiliary pulses are counted in a counter. Each time the counter counts a predetermined number of auxiliary pulses, it produces a signal which either blocks one flowmeter pulse or adds an additional pulse to the flowmeter pulses, in dependence on the polarity of the temperature difference.