摘要:

The paper describes a transistorized digital system for improving the signal/noise ratio of a search radar, by correlating the responses from several successive transmitted radar pulses. The main emphasis in the paper is on the circuit techniques employed.The radar information is first quantized into 2 levels of amplitude (‘0’ and ‘1’) and then into 1024 range elements each of ¼ nautical mile, i.e. 3.09 microsec. The correlation is achieved by counting the ‘1’s stored at each range for a number of consecutive radar p.r.f. periods and deciding whether or not the results are significant. The criteria chosen for this should enable the system to have an overall bearing accuracy somewhat better than the aerial beamwidth.Four separate correlation circuits are used, each handling every 4th range quantum. Thus the clock period is 12.4 microsec, which allows the use of standard magnetic-core-storage techniques.The machine is entirely transistorized and among the circuits described are (a) a precision 323 kc/s triggeredLCoscillator, (b) highspeed logical circuits using transistors and diodes, (c) a high-speed reversible counter and (d) parts of the storage system.

DOI:10.1049/pi-b-2.1959.0126

出版商:IEE    

年代:1959

数据来源: IET

摘要:

The system uses two semiconductor diodes and a capacitor to store each binary bit. At present the store consists of 64 words of 38 parallel bits, with a random-access cycle time at any selected address of 4 microsec.The design of the selection circuits will be described, including a reference to the use of transistors to produce voltage pulses of either polarity having well-defined amplitudes. Reference will be made to the sensing and writing circuits, and also to the selection of diodes for use in the storage elements. In addition, information on reliability gained during operation will be given.

DOI:10.1049/pi-b-2.1959.0127

出版商:IEE    

年代:1959

数据来源: IET

摘要:

The paper describes new types of transistor storage circuits for binary data processing. The active state is denned by the generation of a pulse waveform across the output windings of a transformer which is provided with a multiplicity of output windings, and the timing of the output signal is controlled by a clock waveform coupled to each circuit. This permits the design of logic circuits in which the output voltages generated by different storage circuits are combined additively or subtractively, by series connection of a group of output windings. The inclusion of a diode in each series-connected group allows parallel connection of several groups. In this way logic circuits corresponding to complex logical functions may be constructed in which the only components are diodes. Transistors and resistors may, however, also be included, giving added flexibility in design if required. Any of these logic circuits may be made to control the state of an associated storage circuit by direct connection of the output terminal of the logic circuit to the input terminal of the storage circuit.The storage circuits described are of two types, namely delayed and undelayed. A design is given for a parallel adder in which undelayed storage circuits are used for the ‘carry’ register and in which the addition process is completed in a single clock cycle. In an experimental circuit using type OC44 transistors and operating at a clock frequency of 500kc/s, correct operation is obtained for the addition of numbers up to six binary digits, giving a 7-digit sum. It should be possible to perform parallel operations on much larger numbers at the same clock frequency by using faster transistors in the undelayed storage circuits, while still using relatively low-frequency transistors in the delayed circuits.

DOI:10.1049/pi-b-2.1959.0128

出版商:IEE    

年代:1959

数据来源: IET

摘要:

The paper describes the various circuits associated with a coincident-current ferrite store, all of which use transistors and no valves. A switched-current pulse generator supplies the drive pulses to the store and makes use of the high-frequency power transistor type OC23. Selection is done economically by using gating matrices controlled by transistors. Junction diodes type OA10, or gold-bonded point-contact diodes type OA5, pass the current pulses in the matrices with a very small voltage drop. Two methods of gate selection and drive are described, one of which makes use of square-hysteresis-loop cores to select and drive the gating transistors, and the other uses a diode matrix to provide potential levels at the bases of the gating transistors. The output of the store is amplified by high-frequency transistors, strobed, and standardized. Provision is made for writing new information, or for rewriting information immediately it has been read, by a diode logical network controlling the ‘inhibit’ pulse generator.

DOI:10.1049/pi-b-2.1959.0129

出版商:IEE    

年代:1959

数据来源: IET

摘要:

The digital differential analyser is a type of computer combining digital accuracy with analogue speed and flexibility. Where maximum flexibility is required, the organization of a machine of reasonable size demands many switching elements, and it seems doubtful whether thermionic valves would be sufficiently reliable. Transistors, however, offer sufficient reliability to make a design feasible, and the paper describes several practical circuits which are used in digital differential analysers.

DOI:10.1049/pi-b-2.1959.0130

出版商:IEE    

年代:1959

数据来源: IET

摘要:

The paper describes circuits for performing logical operations in data processing. They operate reliably at 1 Mc/s and at a maximum ambient temperature of 45° C. The logic circuits use an alloy-junction transistor with an alpha cut-off frequency exceeding 10 Mc/s and an aluminium-bonded diode. Complete digital systems can be built using a number of logic units called ‘bricks’, in conjunction with the circulating pulse stores described in a companion paper [Showell, H. A., Barrow, C. W. M., and Collis, R. E. (Convention paper*)]. A set of simple rules determine the interconnections that can be used between units.The logic units described are gates, buffer amplifiers, inhibit-inverter amplifiers, bistable triggers and monostable triggers. D.C. coupling is used between units in order to obtain uniform operation irrespective of the time pattern of the pulse signals. Each one-microsecond digit period is terminated by a common discharge pulse of short duration that restores all transistors, by removing minority carriers from the base regions. No regenerating amplifiers are used, because the circulating pulse stores perform the dual functions of storage and of regenerating pulses, which have suffered attenuation and delay in the logic circuits.Each circuit unit is on a small printed wiring card. These are assembled in the required combinations on larger cards which form convenient plug-in packages.

DOI:10.1049/pi-b-2.1959.0131

出版商:IEE    

年代:1959

数据来源: IET

摘要:

The construction of a Hall-effect multiplier is described and such design features as linearity, frequency response, temperature stability and circuit considerations are discussed. Suggestions are made as to possible uses for this device.

DOI:10.1049/pi-b-2.1959.0133

出版商:IEE    

年代:1959

数据来源: IET

摘要:

The errors produced in a Hall-effect multiplier are examined and shown to belong to one of two categories: either they are due to coupling between input or output, or they are produced by non-linear processes within the device. An estimate of the magnitude of the errors is given and interpreted in terms of carrier leak, modulation leak and envelope distortion for the particular application of a Hall-effect modulator. A comparison is made between plates constructed of indium antimonide and indium arsenide on the bases of carrier suppression, temperature stability, conversion efficiency and distortion. Carrier suppressions of up to 80 dB can be obtained for both materials.

DOI:10.1049/pi-b-2.1959.0134

出版商:IEE    

年代:1959

数据来源: IET

摘要:

Recent developments in airborne radars call for low-noise power supplies at voltages very much greater than the maximum voltage ratings of available transistors.This paper discusses problems in the design of precision high-voltage regulators which can tolerate severe overloads and also meet the stringent requirements of, for example, an f.m. reflex klystron operating over the temperature range −55°C to +65°C.Three basic circuits are described and their inherent power and voltage limitations are discussed. It is shown that high-voltage regulators operating in either the series or shunt mode provide a satisfactory solution, particularly where only a single output is required. However, the most economical approach for the particular case of a reflex-klystron supply is a low-voltage series regulator followed by a square-wave-oscillator type of d.c./d.c. convertor, since the convertor may have a multiplicity of output windings which can, for example, feed the resonator, reflector and filament of the klystron, respectively. The convertor type of design uses a high-current 20-volt regulated supply to control the amplitude of a square-wave oscillator operating at 8.5 kc/s. The output is 500 volts at 90 mA, the conversion efficiency from 20 volts is 80%, and the d.c. stability at the 500-volt level is better than ±0.75 volt from −55 to +65°C. The noise, including ripple, is less than 2 mV (r.m.s.). The addition of a negative-feedback loop between the output of the supply and the low-voltage series regulator improves the d.c. stability and reduces the output impedance.

DOI:10.1049/pi-b-2.1959.0135

出版商:IEE    

年代:1959

数据来源: IET

摘要:

An array of solar batteries for use as the power source of unattended u.h.f. repeaters has recently been established at the top of Mt. Shinobu in Fukushima Prefecture. The equipment consists of two pairs of transmitter-receivers, each of which is partly transistorized. The entire equipment takes approximately 4.5 watts.The silicon solar batteries are used to convert solar energy directly into electrical energy to feed the equipment and simultaneously to charge a set of nickel-cadmium batteries in a floating circuit arrangement as a provision for unfavourable weather.After a series of careful investigations, it became clear that to keep the equipment operating during a long rainy season such as prevails in the Fukushima area, the total capacity of the solar batteries must be designed to be ten times the power actually consumed by the entire equipment. Consequently, the maximum output available from the solar batteries was designed to be about 70 watts. A total of 4320 units were connected to generate 6.5, 60 and 130 volts to supply the transistors, valve heaters and valve anodes respectively.The operating conditions and the reliability of the entire repeater system are discussed in the paper.

DOI:10.1049/pi-b-2.1959.0136

出版商:IEE    

年代:1959

数据来源: IET