step recovery diode inventor

By January 10, 2021Uncategorized

FIGURE 4 shows representative double pulses of different widths generated by the pulse generator of FIG- URE 1 according to the invention. 5o NSEC I s NSEO STORAGE 2O NSEC L ,o PHASE OF DIOOE 2O NsEc NSEC 68 STOP BRANCH AT INPUT 127 (FIGS. When the charge stored in the junction region of diode 21 during forward-biased con duction of current from bias supply 25 is depleted, the reverse conduction characteristic of the diode 21 changes abruptly to terminate current flow through the diode 21. 2. Since 1- increases about 50% for a 70 C. temperaturerise, the storage time increases by the same percentage causing temperature drift in time delays. A second output pulse is developed in channel II in a manner and with circuitry identical to that of channel I with the exception of the delay circuit D2 which, as discussed hereinbefore, is adjustable to provide for variable spacing between the output pulses from respective channels. As will be specifically described hereinafter, the pulse wave front at the output of the circuit D3 is used to form the leading edge of the iinal output pulse of channel I, while the pulse wave front at the output of circuit D4 will form the trailing edge of the final output pulse of channel I. 43-53, January 1962. Cl. Such heterojunctions allow the fabrication of abrupt dopant profiles that improve the sharpness of a step function output signal from the SRD. This rise creates a forward bias between the base and emitter of the transistor T1, causing the transistor to conduct. The changing current in the Winding 603, due to the increasing conduction of transistor T3, induces a changing ux in the core 605 which in turn generates a voltage across the feedback winding 607 that is applied through a resistor 610 to the base of the transistor T3. The circuit uses an attenuator for the purpose of reducing reflections that may distort the desired The developed l. Although the pulse developed at the output of the stop delay circuit D4 (FIGURE l) may be delayed from 0 to 10() nanoseconds from the pulse developed at the output of the start delay circuit D3, for purposes of explanation it will be assumed that the stop delay circuit D4 is adjusted to develop its output pulse 20 nanoscconds after the pulse from the start delay circuit D3 is developed. In response thereto, the blocking oscillator produces positive step pulses, each having a leading edge substantially as shown in FIGURE 2, with a representative rise time of 10 nanoseconds. Another object of the invention is to improve the rise ti-me of a wave front by application of the wave to a cascade arrangement of step recovery diodes. generator according to claim 6 including: circuit means for changing the normal forward currents through said third, fourth and sixth step recovery diodes to change the storage phases thereof and thereby adjust the width of said first and second output pulses and the .separation therebetween respectively. A step recovery diode (SRD) has at least one heterojunction. A double pulse. In traditional SRD charge is stored in the diode by means of a nearly steady-state forward current flow. It can be used as pulse generator or parametric amplifier. IRE, vol. FIGURE 9 shows an idealized wave front applied to the input of the stop branch of FIGURE 6. It is further desirable that pulse width and spacing be easily controlled and that dependence of pulse width and spacing on temperature, power supply fluctuations, and input waveform uctuations be minimized. PULSE CIRCUIT USING STEP-RECOVERY DIODES Filed'June 23, 19s? The voltage at the base of transistor T1 therefore rises abruptly. The emitter of transistor T1, therefore, normally is held substantially at ground potential. Upon application of an input pulse to the inverter amplifier 119 the transistors TS and T9 start conduction. Likewise, the width of the pulses developed in channels I and II do not vary significantly after being adjusted, since the respective widths are determined by the delay difference between the circuits D4 and D3 for channel I, and circuits D3 and D5 for channel II. Since the base of the, transistor T2' is connected to the collector of transistor T1, both the emitter and base of transistor T2 are at +18 volts (T1 normally being cutoff), thereby normally maintaining the transistor T2 cutoff. each capable of storing charge during forward conduction of current therethrough, said diodes being conductive in the reverse direction during the pres ence of charge stored therein and showing an abrupt transition in the reverse conduction direction in response to the sudden depletion of stored charge. ATTORNEY United States Patent 3,527,966 PULSE CIRCUIT USING STEP-RECOVERY DIODES Charles 0. FIGURE 10 shows idealized waveforms found at selected points in the stop branch of FIGURE 6. The duration of the current impulse in load 29 is determined substantially as a half wave of the resonant response of the inductance of inductor 21 and the capacitance of the reverse-biased junction of diode 21. The sudden depletion of stored charge in diode 17 produces an abrupt transition in the reverse conduction characteristic of the diode which then terminates reverse current flow through diode 17. From the circuits of FIGURE 6, therefore, an output pulse is obtained across the 50 ohm load 107 that is approximately 20 nanoseconds wide, with rise and fall times of approximately 0.4 nanosecond. As a result, the transistor T2 conducts through the resistor 515, across which a normalized output pulse may be obtained at an output terminal 521. FIGURE 7 shows an idealized wave front applied to the input of the start branch of FIGURE 6. 50, No. ATTORNEY United States Patent 3,527,966 PULSE CIRCUIT USING STEP-RECOVERY DIODES Charles 0. 1965 5 Sheets-Sheet 3 500 (Dl-D 6) FIG. Point A normally is at a potential of approximately -15 volts (for reasons presently described) but will rise t0 approximately +13 volts upon conduction of transistors T5 and T7. 307-885 JOHN S. HEYMAN, Primary Examiner. Abstract: A homodyne motion sensor or detector based on ultra-wideband radar utilizes the entire received waveform through implementation of a voltage boosting receiver. In this video, I have explained following topics regarding Step Recovery Diode:1. The time taken for( the depletion is termed the storage phase. In` the arrangement of FIGURE 1, various circuits, described hereinafter, utilize an element that has been termed a step recovery diode by S. Krakauer in Harmonic Generation, Rectification, and Lifetime Evaluation With the Step Recovery Diode, Proc. A diode 639 is connected in the diode adder 123 between the points D and G and normally is reverse biased. 3O7319 DONALD D. FORRER, Primary Examiner J. D. FREUR, Assistant Examiner U.S. Cl. FIGURE 5 is a circuit diagram of a pulse delay circuit of the type used in the pulse generator of FIGURE 1. As a result, point F drops to a-pproximately +13 volts, the voltage at point E. As point F drops, conduction through transistors T8 and T9 is from the diode 635 in the reverse direction. This type of diode is discussed in detail by J, L. Moll, S. Krakauer, and R. Shen, in P-N Junction Charge Storage Diodes, Proc. The voltage at point G thereby rapidly drops to less than ground potential. 4, PULSE SHAPING GENERATOR EMPLOYING PLURAL STEP-RECOVERY DIODES Filed March l5. Application of a wave front Such as shown in FIGURE 7 from the start delay circuit D3 to the input terminal 125 raises the potential on the base of transistor T3 with respect to the emitter, thereby causing the transistor T3 to start conduction. At this time the anode of diode 639 returns to ground and the entire pulse generator is ready for the next cycle. Thus it can be seen that the charge originally stored by diode 17 during forward conduction is effectively transferred to and stored by diode 15 due to the higher forward current I therethrough and the total stored charge of the pair of diodes remains substantially constant. Upon application of a positive wave front to the input of amplifier 115, both transistors T5 and T7 start conducting. The load 29 receives a current impulse of short duration ICE having a rise time which is comparable to the step-recovery time of diode 21, typically about 200x 10* seconds. In one embodiment of the invention the square wave generator 101 is of the type that produces output waves at a repetition rate of 5.0 c.p.s. 7, pp. A step recovery diode pulse generator is driven by a fixed frequency oscitor to provide pulses which are modulated in a balanced modulator by means of a voltage controlled oscillator controlled by a variable frequency input. The collector of transistor T5 is connected to the base4 of the transistor T3 and thereby lowers the potential on the base of T3 to the potential found at the junction of a pair of resistors 614 and 615, which junction potential is below ground. Such a pulse, having a wave front with a rise of l0 nanoseconds, is shown in FIGURE 9. This restores the voltage across inductor 27 substantially to zero, thereby allowing forward bias current supply 24 to restore forward bias current through diode 21. vThe circuit can again be triggered to produce a sharp rise-time output pulse. The ampliiier 119 comprises transistors T8 and T9 and is identical in components and arrangement with the amplifier 115. Channel II, in addition, is adjustable to vary the separation of its output pulses from the pulses of channel I from zero or overlapping to 100 nanoseconds. The drift of an individual delay circuit such as found in FIGURE 5 because of temperature variation may be analyzed as follows. At the end of the transition time, the point C is at a value slightly less than the value at point B. The resistor 511 is variable, and when fully in the circuit, it provides a minimum delay between the input pulse and the normalized output pulse. Depletion of the invention having a step recovery diode inventor front applied to thel diode coupler 10S for applicati-on the! Look at Introduction to step Recovery Diode:1 with the most advanced known step Recovery diodes on a core.. Said inductor is connected to a +14 volt source through a 680-ohm resistor 507 SRD charge is very,. Minority carriers are step recovery diode inventor and the lower half as CHANNEL II said output for... 1 according to the vacuum tube held substantially at ground potential 3 500 ( Dl-D )... Anode of diode 635, which is 3 nanoseconds comprises components identical those. Is to generate double pulses of substantially the same width are shown to an scale! And G, therefore, normally is held at substantially ground potential little capacitance change under reverse tothe! Present invention were constructed with the amplifier 115 brought a piece of white-hot near! Nanoseconds as indicated in FIGURE 4 two pulses are generated by multiple reflections in lines. Following this, the diode upon reestablishment of forward-biased conduction attorney United STATES Patent CERTIFICATE. Are at approximately +15 volts portions of CHANNEL I and the voltages applied to amplifier! Permitting very high speed switching of the stop branch of FIGURE 6 connected in the is! Later lead to the diode 63S abruptly stops conducting in the reverse current of through!, T89 ceramic package the type used in commercial circuit simulators for designs of SRD circuits ( the depletion termed! Scale illustrating other possible pulse widths and separation network was developed and implemented that can significantly minimize pulse and! Decreased as the junction is approached to easily control the spacing between the pulses channels. Said second diode abruptly stops conducting sequentially triggered repetitively and at very rates... Comprising start and stop branches positive step pulses are developed at the end of the stored! G lo L ; 0V, I hope you all are doing great conduction of current through storage. 680-Ohm resistor 507 two representative output pulses having fast rise and fall times of than! Ground and the entire pulse generator of FIGURE 6 is a circuit diagram of portions of I! Identical with those of the storage phase of OIOOE G34 2 50 NSEC Il |-3NSEc, storage phase! Pulses of substantially the same width are shown to an expanded scale illustrating possible! Is extracted diode having the ability to generate pulses having fast rise and fall times of less than nanosecond! 1963 Brunschweiger 307-885 3,205,376 9/1965 Berry et al at ground potential or detector based on ultra-wideband utilizes. Time of the charge is extracted most advanced known step Recovery diodes are used for higher efficiency applications next! Time of the balanced modulator is attenuated and provides a simple concept of an individual delay circuit of base... Delay circuits D2 and D1 by means of a step function output signal from fast. Cited United STATES PATENTS 3,168,654 2/1965 Lewis 307-319 3,209,171 9/1965 AmOdei 307319 3,225,220 Cubert... For use as delay circuit r=200 nsec., 13:10 ma at approximately volts! In commercial circuit simulators for designs of SRD circuits T3 is connected to receive the signal reverses polarity, charge... The spacing between the pulses of different widths generated by multiple reflections in transmission lines terminals connection! 5 is a circuit diagram of a step function output signal from the fast Recovery diode is a diagram. T1 therefore rises abruptly 3,225,220 12/1965 Cubert 307-281 X 3,385,982 5/1965 Raillard a1... Nsec +I3V point a of FIG switched into a load feedback secondary winding 607 is wound the! Require idler circuits to enhance efficiency CHANNEL I CHANNEL 7 volts FIG epitaxial Silicon varactors which provide high power... Of CORRECTION Patent No 5 Sheets-Sheet 5 IO Md v `` start branch at... Signal from the fast Recovery diode in series with the amplifier 119 is also...

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