Abstract: Data processing apparatus for processing data relating to information represented by lines on a chart includes two stores, a computer, and a logic unit. One of the stores contains the cartesian coordinates of a plurality of spaced points along the lines while the other store contains the individual elements forming the lines between the spaced points. The computer operates to select sets of elements which may approach within a predetermined area around a point of interest on the chart, while the logic unit checks whether any element actually does fall within this predetermined area.

Abstract: Apparatus for signalling the position of a point on a surface divided into a plurality of identical subsidiary areas includes primary transducer means operable to identify uniquely the subsidiary area in which the point is located, and secondary transducer means representing the sub-divisions of a single subsidiary area. The primary and secondary transducer means may each be represented by a rectangular matrix of light-emitting devices which may be scanned sequentially by scanning means.

Abstract: A floated gyroscope having a float pivoted within a housing for limited rotational movement is provided with a rotational limit control for limiting rotation when the gyroscope is not in use. The rotational limit control includes a locating pin mounted on either the float or the housing, and cooperating limit arms mounted on the other of the float and housing.

Abstract: A pulse circuit for reshaping pulses received over a long line includes a transformer having a primary winding connected to the line and a center-tapped secondary winding. The transformer and the line are together arranged to have a time constant which is short compared to the signal pulse duration. Pulse forming means controlled by the output of the transformer reconstitute the original pulse.

Abstract: A circuit arrangement for use with a scanned-beam moving-surface blemish detector uses the detection of leading-and trailing-edges of the surface in each scan to provide in the following scan a margin or margins, the separation of which provides a measure of the surface width over which detection can take place without the edges being detected as faults. In a modification the margins are extended to the direction of surface movement by introducing a minimum width, between leading-and trailing-edge margins, which must exist before fault detection is permitted.

Abstract: A discrimination circuit arrangement operable to discriminate between signals in the form of d.c. pedestals and superimposed thereon disturbance signals in the form of voltage variations, comprises high pass filter means to remove the d.c. pedestal, except adjacent the leading edge where a decaying impulse is produced by the filter means. A rectangular pulse is generated, triggered by the discontinuity of the pedestal and having an amplitude related to that of the pedestal; the pulse is passed through further high-pass filter means having the same time constant as the input signal filter means to produce a replica signal of the filtered input signal in the form of a decaying impulse, free of disturbance signals. The two decaying impulse signals are compared in comparison means, with a threshold signal, and disturbance signals exceeding the threshold signal produce an output signal.

Abstract: For weighting input signal in accordance with a mathematical transfer function represented by a plurality of straight lines each of which intersects the next at a separate break-point, signal processing apparatus receives or generates a train of pulses, the number of pulses received over a sampling period being related to the signal, and detects preset numbers of pulses corresponding to the break-points, the number detected at the end of the sampling period identifying the highest break-point reached. The detection of each break-point is used to produce an analogue signal corresponding to the value of the break-point and a voltage source is selected corresponding to the gradient of the straight line section following the break-point. Pulses received after each break-point are counted, to be re-set at the next break-point, and the total at the end of the sampling period multiplied by the gradient in a D/A converter to give the analogue value of the signal in excess of the highest break-point.

Abstract: Automatic gain control is provided in a two stage amplifier in which the first stage has a signal voltage gain related to its supply voltage and the second, or output, stage comprises an output transistor. The load of the output stage comprises an earphone in series with the supply. The supply for the first stage is taken from the junction of the output transistor and the earphone such that the gain varies inversely with the output of the earphone. The amplifier stages may be formed as a monolithic integrated circuit and contained in the housing of the earphone.

Abstract: A radar receiver for a frequency-agile radar system includes a variable frequency oscillator and an automatic frequency control operable to exert fine control over the frequency generated by the local oscillator. Control means are provided to derive from a number of previous values of the local ocillator frequency a control signal for application to the local oscillator to bring the generated frequency close to that required for fine correction by the automatic frequency control.

Abstract: A high-speed pulse detection circuit comprises a Schmitt trigger stage connected to a second stage to form a bistable feedback loop having a working characteristic with an infinite gain loop.

Abstract: A multiple-stage binary-coded decimal counter comprises a number of stages each having four preset data input points capable of being energized in parallel binary fashion. A presetting counter is provided, arranged to supply to the preset data input points binary signals representing a decimal digit. The presetting counter is itself actuated by an abrupt signal, and means are provided for selecting the counter stages one at a time for setting from the presetting counter. This last-mentioned means is inhibited except during the presetting procedure.

Abstract: A frequency sensitive switching arrangement is arranged to cause a bistable switching arrangement to produce an output signal at a first or second level depending whether the pulse rate is below a lower rate or above a higher rate with hysteresis preventing change of level between the rates. The bistable switch is arranged to give an output signal at a first or second level in dependence on whether an input pulse is applied to a first or second input. A first monostable element having a first preset unstable period opens a gate to permit pulses to be applied to the second input for the first unstable period and a second monostable element having a second preset unstable period, longer than the first, closes a gate to prevent pulses from being applied to the first input terminal for the second unstable period. Any input pulses occurring between the end of first and second periods is not applied to either terminal and the output level remains as previously.

Abstract: A circuit arrangement for indicating when the pulse repetition frequencies of two pulse trains differ by a predetermined amount comprises a multi-stage shift register containing a binary digit in one of the central stages, pulses from each train are applied to the register alternately by means of clock pulses and individual pulses of each train cause the binary digit to be moved through one stage but in opposite senses. While the repetition frequencies are equal the binary digit oscillates between two stages but if unequal numbers of pulses are received in each train then the binary digit migrates along the stages of the register. An output signal is derived from stages of the register displaced by a predetermined number from the central stages. The circuit is reset after a predetermined number of input pulses so that the percentage difference between the two repetition frequencies is indicated.

Abstract: A logical circuit for maintaining uniform the density of the trace made on a photographic negative by the beam of a CR tube where the beam is subject to displacements in X and Y coordinate directions. The circuit includes a first bistable stage which represents by its state which (X or Y) displacement occurred last, and so controls (by way of a gating network and a second bistable stage) the beam intensity as to briefly reduce it whenever X and Y displacements occur alternately.

Abstract: A multiplier circuit arrangement comprises two parallel paths for the same signal, one of the paths being associated with signal level adjusting means; and means responsive to imbalance of d.c. components including any in said parallel paths, th imbalance being in accordance with a d.c. signal in a third signal path, to produce a control signal for varying the signal level adjusting means to reduce the imbalance, so that a.c. components in said parallel paths will be unbalanced to an extent proportional to the d.c. signal in said third path. Such multipliers are particularly suited to resolving signals in a first set of axes into signals in a second set of axes where other signals are available which are combinable to give trigonometric functions required to translate between the first and second sets of axes.

Abstract: An analog store includes a four-arm resistance bridge in which the resistance of one arm is formed by the drain-source path of a field-effect transistor. The bridge is energised across one diagonal by an alternating voltage and the output is derived from the other diagonal through a high-gain amplifier. The input is applied to the gate of the field-effect transistor. A capacitor is connected between the gate of the field-effect transistor and biasing means.

Abstract: Apparatus in which gold tape is to be servered and placed on selected parts of support members of supports for semiconductor devices has means to feed the tape to severing means including a reciprocatable dog to engage the tape. The dog may pierce or indent the tape, or may frictionally engage the tape.

Abstract: Cardiac monitoring apparatus comprises means for detecting normal and/or ectopic complexes in an electrocardiogram waveform, means for comparing the intervals between successive detected complexes, and means for detecting that successive said intervals differ by more than a predetermined amount. Reversible counters are used in pairs with different counting rates for the counters of each pair to perform the comparing and detecting. Preferably the monitoring apparatus further comprises shifting means arranged to be clocked once for each electrocardiogram complex, whether ectopic or not, and operative to store ectopic indications, and means for indicating that, at any one time, the shift register means contains more than a predetermined number of ectopic indications.

Abstract: A semiconductor device having a plurality of constituent components within a semiconductor body such that the device in combination with one of a plurality of different possible metallisation patterns of conductors forms a desired circuit arrangement, is provided in a semiconductor body having a epitaxial layer of one conductivity type on a substrate of the same conductivity type and suitable to be employed as a conductive plane, and is manufactured by a method which includes the diffusion step of providing simultaneously within the epitaxial layer regions of opposite conductivity type of the constituent components of the device and a network of conductive tracks, it being possible, for example, for the device to include bipolar transistors of the so-called collector-diffusion-isolation construction or isoplanar construction.

Abstract: A support for a semiconductor device comprises a lead frame having a matrix of cranked conductors, which may be on an insulating substrate, with a recess being defined within the lead frame, the arrangement being such that by merely placing a correctly oriented device in the recess, and providing the required electrical interconnections between the device and the conductors, the device is accurately located in its required position on the lead frame.