Patent GB-1320379-A (GB)
Title: Circuit arrangement utilizing oscillatory diode
IPC: H03C3/00
Filed: 1970-09-17
Abstract: 1320379 Pulse generating diode circuits MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 17 Sept 1970 [19 Sept 1969 20 Sept 1969 (4) 28 Jan 1970 (2) 30 Jan 1970 15 June 1970] 44487/70 Heading H3T A circuit arrangement for producing a pulse signal in response or in dependence on an applied input signal, comprises an oscillatory diode 10, Fig. 7(a) having an N-type Ga As wafer bearing spaced electrodes and having a v-layer doped with iron adjacent to one of the electrodes, biasing means 22 for applying a bias voltage to the electrodes, input means 25 for superposing the input signal on the bias voltage so as to initiate or control oscillation of the diode and output means 26, for picking up the oscillation of the diode. The iron doped layer provides a resistive layer and may be formed by diffusion or crystal growth. The electrodes may be of tin alloy or a mixture of gold and germanium. When the voltage applied across the diode is above an oscillation starting threshold (V 1 , Figs. 2 and 3, not shown) avalanche multiplication of carriers and trapping effects take place in the resistive layer and oscillations are produced. The diode 10 may be biased by source 22 below the oscillation terminating voltage so that an input trigger pulse (Fig. 6(a), not shown) of sufficient length and amplitude to raise the voltage across the diode above the oscillation threshold voltage causes a train of output pulses to be generated at 26. Shorter width input pulses each cause only a single output pulse to be generated by the diode (Fig. 6(b), not shown). Applying an input pulse train having a shorter period than that of the output pulses causes the diode to act as a pulse divider (Fig. 6(c), not shown) which may be used for counting such as in a shift register. With the bias voltage from 22 between the oscillation starting and terminating voltages the diode may be triggered by a pulse to produce a pulse train (Fig. 6(d), not shown) until stopped by triggering with a negative input pulse at 25. When the bias voltage is above the oscillation starting voltage a pulse train is obtained the frequency of which depends on the bias voltage. By applying an input sinusoidal trigger signal (Fig. 6(e), not shown) above the oscillation starting voltage the output pulse train is frequency modulated. By omitting load impedance 23 and taking the output across the diode 10 (Fig. 5(b), not shown) an inverted output signal is obtained. By connecting further inputs via capacitors 24 to this modification a NOR circuit is provided (Fig. 9(b), not shown). Similarly by connecting inputs via further capacitors 24 to the circuit comprising 10, 21, 22, 23 in Fig. 7(a) an OR circuit is provided (Fig. 9(a), not shown). These NOR and OR circuits may be combined to form logic circuits. In the pulse delaying circuit Fig. 7(a) an input pulse to 25 causes diode 10 to generate an output pulse across 26 delayed by the time taken for the input to diode 10 to reach its oscillation threshold. This is repeated for diodes 10<SP>1</SP> and 10<SP>11</SP> to produce further delayed outputs at 32, 33. A scanning device may be provided by using all the outputs 26, 32, 33. The delaying circuit can be formed on a singlecrystal substrate in matrix form. In the pulse generator shown in Fig. 8(a) the diodes 10, 10<SP>1</SP>, 10<SP>11</SP> are biased below the oscillation terminating voltage and are interconnected by delaying elements 35, 36. A pulse input (b-1, Fig. 8(b), not shown) to 37 causes diode 10 to generate an output pulse (b-2) at 41 and due to the delay elements 35 and 36 the diodes 10<SP>1</SP> and 10<SP>11</SP> produce sequentially delayed output pulses (b-3, b-4) (6-4) so that a pulse train of three pulses is produced for each trigger pulse applied at 37. The delaying elements 35, 36 may be identical or different. The pulse train produced may be useful for pulse radar. The pulse generating circuit comprising 21-25 and 10 of Fig. 7(a) may be used to drive high frequency oscillator elements such as an avalanche or Gunn effect diode (43, Fig. 10, not shown) or electroluminescent elements or a radiative diode (45) which luminesces when the diode 10 produces oscillation. The high frequency oscillator arrangement (43) may be applied to radar for measuring an object located at a close distance. Specification 1,275,545 is referred to.