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Showing papers on "Rise time published in 1978"


Journal ArticleDOI
H. Ando, H. Kanbe, T. Kimura, T. Yamaoka1, Takao Kaneda1 
TL;DR: In this article, the authors studied the dark current, quantum efficiency, multiplication noise, and pulse response of germanium avalanche photodiodes with n+p junction to find an optimum structure.
Abstract: Dark current, quantum efficiency, multiplication noise, and pulse response of germanium avalanche photodiodes with n+-p junction were studied to find an optimum structure. The dark current can be separated by graphical means into a leakage current component and a multiplied component which flows through the junction. The dark current components are also evaluated by using diodes with various diameters. The quantum efficiency and the multiplication noise are shown to be strongly affected by the n+ layer thickness. An n+ layer thickness optimized for signal-to-noise ratio is estimated from experimental and calculated results, using a figure of merit for avalanche photodiodes. The response waveform for mode-locked Nd:YAG laser shows a rise time of 100 ps and a half pulsewidth of less than 200 ps.

101 citations


Journal ArticleDOI
TL;DR: In this paper, a field-emission-initiated explosive emission process is proposed which involves the formation of a plasma via the volatilization of a small portion of the cone apex.
Abstract: A repetitive pulsed electron‐emission mode has been observed from a liquid Ga/12% In cathode. Current pulses as high as 250 A with a 2‐ to 3‐nsec rise time have been observed at a repetition rate of 40 to 80 000 pps. Emission occurs from the apex of a field‐stabilized cone of the liquid metal which exhibits an incandescent glow corresponding to a temperature rise of ∼1000 °C. A field‐emission‐initiated explosive‐emission process is proposed which involves the formation of a plasma via the volatilization of a small portion of the cone apex.

79 citations


Patent
20 Sep 1978
TL;DR: In this article, a sensor head coupled to an exteriorized artery is coupled with an electromechanical transducers at first and second locations, which convert each periodic arterial pulse pressure wave passing the first-and second locations into first andsecond periodic electrical waveforms.
Abstract: The system of the present invention includes a sensor head which is coupled to an exteriorized artery. The sensor head includes electromechanical transducers at first and second locations which convert each periodic arterial pulse pressure wave passing the first and second locations into first and second periodic electrical waveforms. Electronic circuitry analyzes the first and second periodic electrical waveforms to determine the rise time of each periodic waveform produced by the first and second transducers. This electronic circuitry also analyzes the first and second periodic waveforms to determine the transit time of each pulse pressure wave between the first and second locations. An electronic computer utilizes the rise time and transit time data and certain calibration data to determine and display systolic pressure, diastolic pressure, and pulse rate immediately following each pulse pressure wave. The system of the present invention also computes and displays fifteen beat moving average values of the systolic pressure and diastolic pressure.

77 citations


Journal ArticleDOI
TL;DR: In this paper, the resistive phase of self-breaking water-dielectric spark gaps in a high-current relativistic electron-beam accelerator was investigated experimentally.
Abstract: The resistive phase of self‐breaking water‐dielectric spark gaps in a high‐current relativistic electron‐beam accelerator is investigated experimentally. For gaps that withstand voltages V?1.8 MV and mean electric fields between 2×107 and 5×107 V/m, both the current rise time and the energy dissipated in the discharge are adequately described by the semiempirical relations of Martin. In contrast to the results reported in lower‐energy experiments, no evidence was found of a slowly varying resistive phase with a gap resistance comparable to the circuit impedance after t=2.5τr. Approximately 8±3% of the energy dissipated in the gap is coupled into a shock wave generated by the discharge. Light emission from the arc channels indicated that the light was strongly filtered by the highly excited water surrounding the channel, and the light emission cannot be analyzed to determine the plasma properties of the arc channel unambiguously.

36 citations


Journal ArticleDOI
TL;DR: These results confirm those measured by Shepherd and Sutherland made at 1-ms rise time and above (except for the anomalous enhancement at 250-ms duration), and extend the measurements down to 0.22 ms.
Abstract: A loudspeaker‐driven simulation booth with extended rise‐time capability (down to 0.22 ms) has been used for subjective loudness tests of N‐wave sonic booms. The test series compared signatures over a range of 0.22–10 ms in rise time, 100–250 ms in duration and 0.5–2.5 psf (24–120 Pa) in peak overpressure. In one sequence, the tradeoff between rise time and overpressure was measured for equal loudness; in another, the tradeoff between duration and overpressure. For equal loudness 10‐ms rise time required 8‐dB higher overpressure than for 1‐ms rise time. Duration had little effect in the range 100–200 ms, but at 250 ms noticeably enhanced the loudness. These results confirm those measured by Shepherd and Sutherland made at 1‐ms rise time and above (except for the anomalous enhancement at 250‐ms duration), and extend the measurements down to 0.22 ms. There is also good agreement with theoretical predictions (Johnson–Robinson, Zepler–Harel methods) except for the 10‐ms rise time and 250‐ms duration cases.

33 citations


Patent
10 Aug 1978
TL;DR: In this paper, an operational amplifier within an edge smoothing device has a plurality of independently selectable feedback capacitors each having a different value, and each feedback capacitor has a fast switch responsive to the corresponding bit of a digital binary control word for selecting (1) or not selecting (0) that capacitor.
Abstract: The visual system within an aircraft flight simulation system receives flight data and terrain data which is formated into a buffer memory. The image data is forwarded to an image processor which translates the image data into face vertex vectors Vf, defining the position relationship between the vertices of each terrain object and the aircraft. The image processor then rotates, clips, and projects the image data into two-dimensional display vectors (Vd). A display generator receives the Vd faces, and other image data to provide analog inputs to CRT devices which provide the window displays for the simulated aircraft. The video signal to the CRT devices passes through an edge smoothing device which prolongs the rise time (and fall time) of the video data inversely as the slope of the edge being smoothed. An operational amplifier within the edge smoothing device has a plurality of independently selectable feedback capacitors each having a different value. The values of the capacitors form a series which doubles as a power of two. Each feedback capacitor has a fast switch responsive to the corresponding bit of a digital binary control word for selecting (1) or not selecting (0) that capacitor. The control word is determined by the slope of each edge. The resulting actual feedback capacitance for each edge is the sum of all the selected capacitors and is directly proportional to the value of the binary control word. The output rise time (or fall time) is a function of the feedback capacitance, and is controlled by the slope through the binary control word.

28 citations


Journal ArticleDOI
TL;DR: Over 1/4-joule per pulse is obtained from a cable-fed uv preionized discharge device where a faster energy deposition rate compensates for a slower voltage rise time.
Abstract: Over 1/4‐joule per pulse is obtained from a cable‐fed uv preionized discharge device where a faster energy deposition rate compensates for a slower voltage rise time. These slower voltage rise‐time devices may be scalable to high repetition rates using conventional thyratron switching techniques.

25 citations


Journal ArticleDOI
TL;DR: In this paper, the time resolution capabilities of prototype microchannel plate and static crossedfield photomultipliers have been investigated, and the experimental data have been compared with results obtained with conventionally designed RCA 8850 and C31024 high speed photomorphiers.
Abstract: The time resolution capabilities of prototype microchannel plate and static crossedfield photomultipliers have been investigated. Measurements were made of electron transit time, rise time, time response, single photoelectron time spread and multiphotoelectron time spread for LEP HR350 proximity focused high gain curved microchannel plate and VPM-154A/1.6L static crossed-field photomultipliers. The experimental data have been compared with results obtained with conventionally designed RCA 8850 and C31024 high speed photomultipliers. Descriptions are given of both the measuring techniques and the measuring systems.

22 citations


Journal ArticleDOI
TL;DR: The effects of frequency and signal rise time were confounded, no frequency effect was apparent and response amplitude and detectability decreased and response latency increased.
Abstract: Two experiments studied the effects of signal rise time and frequency on the brainstem auditory evoked response. In Experiment 1, five different rise times were presented, fast (10 µsec), 0.5, 1, 2...

18 citations


Journal ArticleDOI
TL;DR: In this paper, a transistor-distributed amplifier configuration was developed and tested for medium power applications, which achieved a 10 dB gain, 130 ps step response rise time, and a amplitude of 4 V peak to peak across a 50 /spl Omega/ load.
Abstract: In order to build a gigabit/second pulse amplifier for medium power applications a new transistor-distributed amplifier configuration was developed and tested. A five-section amplifier employing 5 GHz f/SUB T/ bipolar transistors has a frequency response from DC to 3.6 GHz. Results achieved were a 10 dB gain, 130 ps step response rise time, and a amplitude of 4 V peak to peak across a 50 /spl Omega/ load.

9 citations


Journal ArticleDOI
TL;DR: In this article, a system for shaping the output pulse of a Q-spoiled laser is described, which produces light pulses having a half-peak width no greater than 250 ps.
Abstract: A system for shaping the output pulse of a Q-spoiled laser is described. With this system, light pulses having a half-peak width no greater than 250 ps have been produced. Equally as important, there is only a marginal decrease, due to the additional optical circuitry, in the peak intensity value between the original Q-switched pulse and the final shaped pulse. A laser-triggered spark gap is used to generate the controlling electrical pulses which are generated with a rise time of less than 180 ps. The design of a Pockels cell is described which has an optical aperture of 5 mm and an electrical rise time of 74 ps.

Journal ArticleDOI
TL;DR: In this paper, the rise time of a gas-filled photodiode at blue-green wavelengths is found to be less than that at red wavelengths, and it is suggested that these phenomena decrease parasitic inductance of the tube.
Abstract: The rise time of a gas-filled photodiode at blue-green wavelengths is found to be less than that at red wavelengths. As photoionization of excited atoms in such devices increases response to light of decreasing wavelength over that provided by the photocathode, spectral differences in rise time are also attributed to the same mechanism. It is suggested that these phenomena decrease parasitic inductance of the tube. This implies that rise times in glow discharge detectors of EM radiation can be improved through miniaturization of inter-electrode spacing.

Journal ArticleDOI
TL;DR: In this paper, a charge-sensitive preamplifier is used to produce short current pulses of a width equal to the collection time of the detector, and these pulses are integrated by the charge sensitive pre-plifier which produces a voltage step at its output.
Abstract: The usual requirement for a spectrometer system is to provide the best energy resolution that can be obtained with a set of given experimental constraints. These constraints can change with each experiment, and the experimenter should be able to optimize the parameters of the spectrometer to obtain the best results. The detector, either silicon or germanium, is connected to a charge-sensitive preamplifier. The detector produces short current pulses of a width equal to the collection time of the detector. These are integrated by the charge-sensitive preamplifier which produces a voltage step at its output. The output step rise time is equal to the collection time of the detector, its amplitude is equal to the input charge divided by the capacitance of the feedback capacitor, and its decay time constant is determined by the preamplifier feedback components.

Patent
30 Aug 1978
TL;DR: In this article, a remotely controlled chroma key soft edger is described for use with an analog switcher, where the keying signal is a low passed filtered and differentially summed with substantially an unfiltered keying signals and the resultant high frequency components are summed with the low pass filtered signal.
Abstract: A remotely controlled chroma key soft edger is described for use with an analog switcher. The keying signal is a low passed filtered and differentially summed with substantially an unfiltered keying signal and the resultant high frequency components are summed with the low pass filtered signal. The gain of the peaking signal is remotely controlled to adjust the summed rise time of the keying signal.

Journal ArticleDOI
TL;DR: In this paper, a high-voltage pulse generator is described which produces 20 kV rectangular pulses having 10 ns rise and fall times, a duration from 30 ns up to milliseconds and repetition rates up to 50 pulses s-1.
Abstract: A high-voltage pulse generator is described which produces 20 kV rectangular pulses having 10 ns rise and fall times, a duration from 30 ns up to milliseconds and repetition rates up to 50 pulses s-1. The main advantages of the device over customary circuits are low jitter, small triggering power and large range of pulse width.

Journal ArticleDOI
TL;DR: The transfer function obtained from the tuncated expansion of exp(p) in series of Bessel polynomials yield an approximation of the ideal filter as mentioned in this paper, thanks to a freely chosen parameter, it is possible to control the compromise between optimal amplitude and phase or between the rise time and the overshoot of the step response.
Abstract: The transfer function obtained from the tuncated expansion of exp(p) in series of Bessel polynomials yield an approximation of the ideal filter. Thanks to a freely chosen parameter, it is possible to control the compromise between optimal amplitude and phase or between the rise time and the overshoot of the step response. Compared to the classical Thomson characteristic, which is linked to a single Bessel polynomial, the delay deviation in the passband is smaller.

Journal ArticleDOI
TL;DR: In this article, an integrated system is described measuring currents and voltages without any interference by using the Faraday and Kerr effects, which can be used with different sensitivities within the range 10-150 kV.
Abstract: For a quantitative description of the fast, self-sustained, high-pressure gas discharges used in transversely excited gas lasers the waveforms of current and voltage must be known accurately. An integrated system is described measuring currents and voltages without any interference by using the Faraday and Kerr effects. The sensitivity of the current measurement is 20 mV kA-1. The Kerr cell can be used with different sensitivities within the range 10-150 kV. The rise time of each detector system is 5 ns.

Journal ArticleDOI
TL;DR: In this paper, the authors report on practical measurements of the rise times generated by the laser-triggered spark gap (LTSG) which show that, for a certain gap setting, there is a minimum rise time that may be achieved and that the parameters, voltage and pressure, which are determined theoretically to give this minimum rise times are in reasonable agreement with the practically measured values.
Abstract: The laser-triggered spark gap (LTSG) has found uses in many applications where ultra-fast voltage transitions are required, primarily because of its reliability of operation, simplicity of construction and speed of response. The LTSG can be incorporated into most coaxial systems with minimum change of impedance, a necessary condition to achieve fast electrical switching. The authors report on practical measurements of the rise times generated by the LTSG which show that, for a certain gap setting, there is a minimum rise time that may be achieved and that the parameters, voltage and pressure, which are determined theoretically to give this minimum rise time are in reasonable agreement with the practically measured values.

Patent
04 Dec 1978
TL;DR: In this article, a position sensitive proportional counter circuit is provided which allows the use of a conventional (low-resistance, metal-wire anode) proportional counter for spatial resolution of an ionizing event along the anode of the counter.
Abstract: A position-sensitive proportional counter circuit is provided which allows the use of a conventional (low-resistance, metal-wire anode) proportional counter for spatial resolution of an ionizing event along the anode of the counter. A pair of specially designed active-capacitance preamplifiers are used to terminate the anode ends wherein the anode is treated as an RC line. The preamplifiers act as stabilized active capacitance loads and each is composed of a series-feedback, low-noise amplifier, a unity-gain, shunt-feedback amplifier whose output is connected through a feedback capacitor to the series-feedback amplifier input. The stabilized capacitance loading of the anode allows distributed RC-line position encoding and subsequent time difference decoding by sensing the difference in rise times of pulses at the anode ends where the difference is primarily in response to the distributed capacitance along the anode. This allows the use of lower resistance wire anodes for spatial radiation detection which simplifies the counter construction and handling of the anodes, and stabilizes the anode resistivity at high count rates (>106 counts/sec).

ReportDOI
31 Dec 1978
TL;DR: In this article, a loudspeaker-driven simulation booth with extended rise time capability (down to 0.22 ms) has been used for subjective loudness tests of sonic-boom and other types of impulsive sounds.
Abstract: : A loudspeaker-driven simulation booth with extended rise time capability (down to 0.22 ms) has been used for subjective loudness tests of sonic-boom and other types of impulsive sounds. The first series compared N-waves over a range of 0.22 to 10 ms rise time, 100 to 250 ms duration and from 0.5 to 4 psf (the latter for the longer rise times) (24 to 192 N/sq m) peak overpressure. The response tradeoff between rise time and overpressure, and duration and overpressure was measured. The second series tested certain 'flat top' sonic boom signatures, which according to current theory could be generated by special very long SST aircraft designed for minimized sonic-boom; these were compared for loudness with a reference N-wave (pN = 0.5 psf, 1 ms rise time, 150 ms duration). The third series compared filtered N-wave signatures, using a highpass digital filter with an unfiltered N-wave signature (1 psf, 1 ms rise time, 150 ms duration). In the last test series the tradeoff between overpressure and duration was found for idealized quarry blast signatures composed of sequences of 25 ms long pulses with 0.22 ms rise time. The range of durations extended from 25 to 400 ms. The results in each series were compared with theoretical predictions by the method of Johnson and Robinson. All but the long-duration quarry blast judgements were found to be in very good agreement in terms of relative loudness levels.

Patent
17 May 1978
TL;DR: In this paper, an active filter oscillator is constituted by RC active filter 14 constituted dependently upon the state variable method, constant-current source 19, transistors (TR) 15 and 16, the amplitude limiting circuit consisting of resistances 21-24, and TR17 which operates as an analogue switch.
Abstract: PURPOSE:To shorten the rise time of the oscillation signal or transmission and the fall time of the oscillation signal for receiving, by constituting an active filter oscillator by an active filter, an amplitude limiting circuit, and a transistor switch. CONSTITUTION:An active filter oscillator is constituted by RC active filter 14 constituted dependently upon the state variable method, constant-current source 19, transistors (TR) 15 and 16, the amplitude limiting circuit consisting of resistances 21-24, and TR17 which operates as an analogue switch. Time t2 for switching from the oscillation mode to the reeiving mode is synchronized with the fall time of the output signal, and the collector DC voltage of TR16 applied at the oscillation time is adjusted, thereby generating the signal of a phase opposite to that of the output signal after t2. As a result, the fall of the oscillation signal is very rapid.

Journal ArticleDOI
TL;DR: In this paper, it is shown that the resolution of a t.r.d. system can be improved beyond the classical limit imposed by the rise time of the step generator.
Abstract: By application of the principles of super timing (i.e. sharpening of the time resolution for a given bandwidth) it is shown that the resolution of a t.d.r. system can be improved beyond the classical limit imposed by the rise time of the step generator. The discussion is supported by experimental results.

Patent
15 Apr 1978
TL;DR: In this paper, a shortening of the rise time of output voltage was proposed by raising the base potential for series connection with a transistor for error detection made cutoff when the output voltage is bleow the set voltage.
Abstract: PURPOSE:To promote a shortening of the rise time of output voltage, by raising a base potential for series connection with a transistor for error detection made cutoff when the output voltage is bleow the set voltage.

Patent
01 Jun 1978
TL;DR: The transistorized switching circuit for the car accessory is provided with two transistors(T1, T2) with the emitter of the first coupled to a potential divider (R2, R3) at a point between it and a load(R5) as discussed by the authors.
Abstract: The transistorised switching circuit for the car accessory is provided with two transistors(T1, T2) with the emitter of the first coupled to a potential divider (R2, R3) and to the emitter of the second transistor, at a point between it and a load(R5). A diode(D2) couples the base of the first transistor to the collector of the second. The circuit provides a fast rise time to switch off the accessory after the set time interval. It dispenses with holding relays, and is able to cope with large switching currents. It can be used for the fuel fired heater of a vehicle, in which a safety cut-out mode is introduced when the ignition is off.

Patent
14 Dec 1978
TL;DR: In this paper, a DC excitation winding is set up in a saturated reactor to adjust the rise time of a switching element through the adjustment of the excitation current, which facilitates the material selection of a saturated Reactor and the setting of inductance.
Abstract: PURPOSE:To facilitate the material selection of a saturated reactor and the setting of inductance by setting up a DC excitation winding in the saturated reactor and freely adjusting the rise time of a switching element through the adjustment of the DC excitation current.

Journal ArticleDOI
TL;DR: In this paper, it was shown that the initially fast decay turns over in an exponential decay with a time constant of about 30 ns, and a simple algorithm was presented that corrects the recorded waveform for the effects of this tail.
Abstract: Discusses the time resolution of p-i-n photodiodes applied as electron detectors. The rise time was found to be of the order of 1 ns, which is equal to that in the case of photon detection. However, it appears that in electron detection the initially fast decay turns over in an exponential decay with a time constant of about 30 ns. A simple algorithm is presented that corrects the recorded waveform for the effects of this tail.

Journal ArticleDOI
TL;DR: In this article, the nearly linear dependence of pulse height and rise time on the distance a pulse travels along delay-line readouts of multiwire proportional chambers is shown to be useful for improving the position resolution obtainable from such chambers.

Patent
13 Jul 1978
TL;DR: In this article, the PN junction diode was used as the pull up element in the bootstrap circuit in the capacitive load driving unit integrated on a semiconductor substrate.
Abstract: PURPOSE:To quicken the rise time, by using the PN junction diode as the pull up element in the bootstrap circuit, in the capacitive load driving unit integrated on a semiconductor substrate.

Journal ArticleDOI
TL;DR: A simple and fast photometric signal processing unit has been constructed using some of the commonly available linear and digital integrated circuits to achieve common mode rejection ratio of 75 dB and rise time of 0.2 mus.
Abstract: A simple and fast photometric signal processing unit has been constructed using some of the commonly available linear and digital integrated circuits. A common mode rejection ratio of 75 dB, based on the subtraction of the output and reference signal, and a rise time of 0.2 μs have been achieved with this instrument.

Journal ArticleDOI
TL;DR: In this paper, the design of an equal-ripple modulator for regulator systems with type o plants is presented, which produces an equalripple steady-state response regardless of system parameter values.
Abstract: The design of an equal-ripple modulator for regulator systems with type o plants is presented in this paper. The goal of this design is to produce an equal-ripple steady-state response. To conserve the control effort, rids modulator drives the system output towards the desired level and lets it relax naturally to the zero-state. A number of systems using this modulator were simulated on a digital computer and the results are presented. It can be seen from these results, that the modulator achieves an equal.ripple steady-state response regardless of system parameter values. To employ the modulator in a control system requires only a noncritical choice of the pulse height and width. Large pulse sizes will decrease the transient rise time but will increase the magnitude of the steady-state error. As the modulator threshold level is obtained recursively from information gained from the system error, it possesses "adaptive" qualities. Therefore, it particularly recommends itself to situations in which system parameter variations are expectecd.