Sweep Circuit Research Articles

Streak tube imaging lidar with kilohertz laser pulses and few-photons detection capability

Lidar using active light illumination is capable of capturing depth and reflectivity information of target scenes. Among various technologies, streak tube imaging lidar (STIL) has garnered significant attention due to its high resolution and excellent precision. The echo signals of a STIL system using single laser pulse are often overwhelmed by noise in complex environments, making it difficult to discern the range of the target. By combining high-frequency laser pulses with the repetitive sweep circuit, the STIL system enables efficient detection of few-photons signal in weak-light environments. Additionally, we have developed a robust algorithm for estimating the depth and reflectivity images of targets. The results demonstrate that this lidar system achieves a depth resolution better than 0.5 mm and a ranging accuracy of 95 um. Furthermore, the imaging of natural scenes also validates the exceptional 3D imaging capability of this system.

INVESTIGATION OF THE MECHANISM OF THE PRESSURE WAVES DISTRIBUTION IN THE INJECTED FLUID FROMTHE WELLHEAD TO THE BOTTOM HOLE

Based on the analysis of the existing material on pumping liquids with pressure pulses into the borehole we suggest to consider wellhead injection. The processes of the pressure pulse propagation in the pumped liquid by using wellhead pulsers. Based on the mathematical expressions graphs of the pressure values of the borehole depth and radius sweep circuit are constructed. According to the results recommendations are given on the development of optimal wellhead pulser designs.

Energy feedback used for oscillators control

There are many types of oscillators and many different circuit configurations that produce oscillations. Some oscillators produce sinusoidal signals, and others produce nonsinusoidal signals. Nonsinusoidal oscillators, such as pulse and ramp (or sawtooth) oscillators, find use in timing and control applications. Pulse oscillators are commonly found in digital-systems clocks, and ramp oscillators are found in the horizontal sweep circuit of oscilloscopes and television sets. Sinusoidal oscillators are used in many applications, for example, in consumer electronic equipment (such as radios, TVs, and VCRs), in test equipment (such as network analyzers and signal generators), and in wireless systems. There are two widely used methods of oscillator amplitude control. In the first method, the oscillator active element has a nonlinear characteristic of the limiting type. In the second method the oscillator active element has linear control of gain. In this paper a new method of control based on state energy concept is proposed. It will show that system controlled by a linear controller with energy feedback can generate different types of signals. Depending on parameters of the controller the generated output signal can be sinusoidal, nonsinusoidal, or even chaotic. A new chaotic attractor was found by means of state energy feedback.

A new optical oscilloscope

A new optical oscilloscope has been developed on the basis of the image-converter tube camera technology. Optical or electrical pulses in single or repetitive mode can be tested. When single pulse without time dependence on the sweep circuit is tested, an optical-fiber delay unit is adopted to ensure the pulse is captured. The optical oscilloscope works at a fixed frequency while repetitive pulses of any frequency less than 20 GHz were tested. A newly designed photocathode optical oscilloscope tube, control circuits, and a linear charge-coupled device readout system have been incorporated into the optical oscilloscope. Experimental results show that the temporal resolution of the optical oscilloscope is better than 5 ps, the spectral response range is 380–850 nm, and the single pulse can be captured with the probability of 100%.

High-dynamic-range laser-pulse-contrast measurement with a plasma-shuttered streak camera

The dynamic range of a picosecond visible streak camera has been improved by the combination of a plasma shutter and multishot averaging performed with a photoconductive switch sweep circuit. We use this technique to measure the contrast of a 100-fs laser pulse over 2 ns with a dynamic range of 7 orders of magnitude.

A simple and compact high-voltage switch mode power supply for streak cameras

The design and development of various high-voltage switch mode power supplies (SMPSs) for use with streak cameras are described. This work details -15 kV(), (1 mA) and (1 mA) SMPSs for biasing the streak and image intensifier tubes, driving the sweep circuit and positioning the photoelectron beam on the phosphor screen of the streak camera respectively. The design of the high-frequency pulse transformer - the main part of these SMPSs - is also presented.

Sweep circuit design for a picosecond streak camera

A review of the operation of a streak camera is presented. This is followed by a discussion of measurement techniques with time resolutions on the order of 1 ps using the streak camera. A sweep circuit design is presented using power metal oxide semiconductor field effect transistors (MOSFETs). The sweep circuit generates two ramps of +or-2 kV in amplitude. With these ramps sweep times of less than 5 ns (125 ps mm-1) to greater than 200 ns are achieved. The time-base variation is adjustable with a DC voltage provided by a front-panel potentiometer (knob) similar to an oscilloscope.

Improvements In Avalanche-Transistor Sweep Circuitry For Electro-Optic Streak Cameras

We have improved the performance of the avalanche-transistor deflector-driver (sweep) circuitry used in the high-speed, electro-optic streak camera at Lawrence Livermore National Laboratory. In the previous design for the sweep circuit, trigger-to-output delay time drifted on some cameras. This delay drift is a function of a somewhat randomly unstable breakdown voltage of some avalanche transistors. Both temperature and differences in manufacturing methods for transistors affect this instability. However, a significant improvement in system performance is achieved by long-term burn in and by selection of only the most stable transistors for the sweep circuit. The peak-to-peak sweep voltage has been increased about 80% by increasing the number of avalanche transistors in the string and raising the quality factor (Q) of the resonant circuit. The result is an improvement in sweep uniformity by a factor of approximately 2. Design equations for selecting components are given. Fast-recovery diodes are used to prevent undershoot and to keep the beam out of the intensifier field of view until after the intensifier is gated off. The sweep time range has been extended to over 100 ns.

Design of a Contourograph Using Integrated Circuits

Many physiological signals happen to be quasi-periodic because of the presence of a natural clock, the heart; and are nonidentical because of the variation in biological activity with time. The contourograph is a device for visual presentation of such quasi-periodic and nonidentical data in a compact form. This paper describes an accessory unit that has been developed to convert a laboratory CRO into a real-time contourograph.Most of the features required for this type of presentation are present in a normal oscilloscope except that the horizontal sweep circuit cannot be retriggered until the beam has traversed the full screen and hence a retrace, which may be required in case a significant event occurs in this period, cannot be provided on demand. Other major modifications needed are in the intensity circuit and the addition of a slow sweep to the vertical channel to form a raster display. For the proposed accessory unit, the slow sweep, intensity control and horizontal sweep circuits needed for the cont...

Tangent sweep circuit

A tangent sweep circuit for application in recording of airborne i.r. line-scan data is described, which uses only low-cost components. Sweep parameters are directly related to circuit parameters, and a sweep velocity signal is available. Minor modifications give hyperbolic or hyperbolic-tangent waveforms.

Horizontal Output Transistor Base Circuit Design

The recently introduced high voltage power transistor has found increasing usage in such applications as TV horizontal sweep circuits, switching regulators and other switching applications. A serious problem confronting the circuit designer is how to design circuitry so that transient switching losses are minimized. It is the purpose of this paper to discuss some of the aspects of device behavior and circuit design which can lead to optimum performance with respect to fast current fall at turn off.

A precision monolithic time delay generator for use in automotive electronic fuel injection systems

A high-performance low-cost IC time-delay generator has been developed to be used as a building block for automotive electronic fuel injection systems. Time-delay accuracies are achieved by employing the IC to precisely control both the reset time and the initial ramp voltage of an external RC voltage sweep circuit by means of a gated voltage regulator. Reference information, derived from the rotating distributor shaft, triggers an input flip-flop that controls a reset generator to produce the required gating pulses. The resulting exponential voltage sweep is sensed at the input of three externally programmable voltage comparators that provide three separate time-delayed output signals within a /spl plusmn/1-percent accuracy from -40/spl deg/ to +125/spl deg/C. This technique is contrasted to a linear voltage sweep approach which offers less desensitivity to IC parameter variations.

Transverse section scintigraphy by means of rotating cathode ray tube.

A method of taking transverse section scintigram, using a rotating cathode ray tube with a sweep circuit, is described. A rotating table for a patient is prepared, which is set so as to be that the rotation center of a rotating table should be placed within the perpendicular line from the center of the detector facing sideways. A rotating table rotates synchronously with rotation of the deflection coil of CRT. Two points 2.5 cm apart from each other could narrowly resolved in a transverse section scintigram thus obtained. This method has some characteristics differ from those have already been reported by others.

A transistorized point on a wave selector†

A transistorized point on a. wave selector which gives a 200 volts positive pulse at any desired point on an input sine wave is explained. It can work either in single shot or in repetitive mode. The circuit ia synchronized with the input sine wave shape on any point of which a pulse is needed, and tho output voltago pulse is obtainod only when the sinusoidal voltage is present. It also gives a positive trigger pulso which can trigger an oscilloscope sweep circuit. The trigger pulse leads the output pulso ao that at least one cycle of the sine wave will bo displayed on the oscilloscope screen before tho output pulse.

An improved method of coulostatic titrations

The complexities of performing coulostatic titrations have been greatly reduced by using a special external sweep circuit which produces a horizontal sweep rate for the oscilloscope that varies with the square root of time. Since the potential decay at a large H.D.M.E. also varies with the square root of time and was applied to the vertical plates, linear decay curves were obtained. The slopes of the linear decay curves were plotted against volume of titrant. Lead and cadmium were titrated successfully in the concentration range of 4.4·10 -6-4.7·10 -5 M.

Current Sweep Circuit with Sweep Speed Feedback

A current sweep circuit is described which allows the quick and accurate recording of narrow current peaks in the I-V characteristic of a Josephson tunnel junction driven by the circuit. A feedback feature senses the current peaks and slows the sweep rate in these regions to allow for the finite slewing speed of the X-Y recorder. The performance of the circuit is demonstrated using a simple test arrangement.

A Simplified Color Television Camera

A three-vidicon live-color TV camera has been designed primarily for closed-circuit use, but it can be adapted for broadcasting. Its demagnifying relay system simplifies optical problems. The 35mm single-lens-reflex format was chosen for the objective lens to maximize lens availability and minimize cost. Plate beamsplitters employing dichroic coatings were computer designed to minimize hue shift and polarization and angle difference. The camera is completely self-contained and includes sync generator and encoder, requiring only 117-V ac power and a single coaxial output connection. Optical and mechanical alignment is factory set with precise jigs; the critical optical elements are sealed in a single removable subassembly. The stable sweep circuits require an absolute minimum of adjustment for achieving and maintaining registration. Other design features are: video circuits to provide stability of gain and dc level; a crystal-controlled syncgenerator; the camera adaptable to systems of any complexity; and remote control of all critical operating parameters. Sensitivity enables usable color pictures to be obtained with as little as 75-fc illumination.

Simple Electronic Linear Sweep Circuit for Current-Regulated Magnet Power Supplies

Simple Electronic Linear Sweep Circuit for Current-Regulated Magnet Power Supplies

Characteristics and Applications of Vidicon Scan Converters

This paper discusses the use of a vidicon storage tube in scan converter operations. It outlines the design considerations and pertinent characteristics of devices employing the storage vidicon in scan converter applications. It discusses optics, transfer characteristics and sensitivity considerations. It discusses the significant factors in choosing tube type, sweep circuits, and other associated electronics when assembling a special purpose instrument. It outlines modifications and operating techniques when utilizing an ordinary TV camera. Instruments designed and built by NOLC, both a general purpose laboratory instrument and an airborne unit, are described. The paper concludes by giving a number of example applications.

Solid-state bootstrap sweep generator

An analysis of the bootstrap-integrator sweep circuit is presented which is applicable to circuits using both field-effect and bipolar transistors. Sources of error are investigated, and it is shown that ramp rates ranging from 0 1 V/s to 10 MV/s may be generated with high accuracy.