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Voltage-to-frequency converter, with ultra-high input impedance and linear response, is used in analog to digital data conversion systems. Voltage-to-current converter, using MOSFET devices and a multivibrator, has ultra-linear voltage-to-frequency characteristics. It replaces voltage sensitive magnetic-core oscillators.
Millimeter-wave frequency converters on a diode with a Schottky barrier were analyzed. The analysis includes investigation of the effect of the variable capacitance of the diode's elements on the frequency converters. Specifically, the transmission, impedance, and noise characteristics of the frequency converters were examined.
Pneumatic analog-to-pulse frequency converter circuit has output pulse frequency proportional to the pressure level of the input signal. Converter circuit drives a pneumatic stepping motor and is part of a pneumatic control system for nuclear powered spacecraft.
Fluidic analog to pulse frequency converter for pneumatic reactor control drum actuator system
Controlling the frequency of a square-loop magnetic core oscillator using a dc voltage to give a voltage-to-frequency conversion for use in pulse frequency modulated telemetry systems
Output autocorrelation function and power spectral density of diode frequency converter
Quantum frequency conversion serves a key role in the realization of hybrid quantum networks by interfacing between wavelength-incompatible platforms. Here we present what is believed to be the first quantum frequency converter connecting visible and telecom domains on a silicon nitride (SiN) chip, using Bragg-scattering four-wave mixing to upconvert heralded single photons from 1260 to 698 nm, which covers a 192 THz span. We examine the noise sources in SiN and devise approaches to suppress noise photons at the source and target frequencies to enable measurements at the single-photon level. We demonstrate an on-chip conversion efficiency of 5% in photon flux and describe design modifications that can be implemented to significantly improve it. Our results pave the way for the implementation of complementary metal-oxide-semiconductor (CMOS)-compatible devices in quantum networks.
Recently, studies on the commercialization of magnetic resonance wireless power transfer (WPT) systems are underway domestically and internationally. The magnetic resonance WPT technology enables power transmission between transmitter and receiver coils with the same resonance frequency. If the resonance frequencies of the transmitter coil and receiver coil are different, the efficiency of the WPT will rapidly decrease. Various organizations, such as A4WP, have been striving to standardize resonance frequencies, but the countries around the world are sticking to their own distinctive standards based on the frequency bands available in their territories. Therefore, each country uses a slightly different resonance frequency band. In this paper, a frequency converter that enables WPT when the transmitter and receiver coils have different resonance frequencies is proposed. The frequency converter consists of two coils, and its structure is very simple. The two coils transmit power using the magnetic induction method, and frequency variation is possible using variable capacitors. It was confirmed from the experiment that WPT is possible even if the resonance frequencies of the transmitter and receiver coils are different.
A voltage to frequency converter (VFC) for general use with photomultipliers is described. For high light levels, when the dead-time corrections for a photon counter would be excessive, the VFC maintains a linear response and allows the recording of data at high time resolution. Results of laboratory tests are given for the signal-to-noise characteristics, linearity, stability, and transient response of the VFC when used in conjunction with EMI 9658 and RCA C31034 photomultipliers.
This paper discusses total dose effects on voltage-to-frequency converters which impose different requirements on internal circuitry, and are also very high-precision devices (for example, linearity is typically specified between 0.002 and 0.05%).
A new Static Frequency Converter (SFC) system has been installed and tested at the NASA Glenn Research Center s Central Air Equipment Building to provide consistent, reduced motor start times and improved reliability for the building s 14 large exhausters and compressors. The operational start times have been consistent around 2 min, 20 s per machine. This is at least a 3-min improvement (per machine) over the old variable-frequency motor generator sets. The SFC was designed and built by Asea Brown Boveri (ABB) and installed by Encompass Design Group (EDG) as part of a Construction of Facilities project managed by Glenn (Robert Scheidegger, project manager). The authors designed the Central Process Distributed Control Systems interface and control between the programmable logic controller, solid-state exciter, and switchgear, which was constructed by Gilcrest Electric.
This letter describes a resonantly two-photon pumped frequency converter with application to the generation of tunable ultraviolet and vacuum ultraviolet radiation and also to infrared-to-visible up-conversion and imaging. Calculations show that up-conversion power efficiencies in excess of 100% should be obtained with tunable dye lasers having peak powers in the hundred watt to kilowatt range.
A time-to-frequency converter was constructed using an electro-optic phase modulator as a time lens, allowing the pulse shape in time to be transferred to the frequency domain. We used such a device to record the temporal shape of infrared pulses at a wavelength of 1053 nm (width about 7 ps) and compared these measurements to those made by using both a streak camera and an autocorrelator. This side-by-side comparison illustrates the benefits and limitations of each of the measurement methods. Numerical simulations were used to establish that our time-lens-based system can accurately measure the shape of infrared pulses between 3 ps and 12 ps. We also use our numerical model to determine how such a system can be modified to measure pulses whose width lies in the range of 1–30 ps, a range of interest for the OMEGA-EP laser at the Laboratory for Laser Energetics.
A simple, direct procedure was developed for converting frequency domain aerodynamics into indicial aerodynamics. The data required for aerodynamic forces in the frequency domain may be obtained from any available (linear) theory. The method retains flexibility for the analyst and is based upon the particular character of the frequency domain results. An evaluation of the method was made for incompressible, subsonic, and transonic two dimensional flows.
Measurements of pressures on walls of wind tunnels and on surfaces of models in wind tunnels made with help of electronically scanned pressure-measurement (ESP) system. Voltage-to-frequency converter circuit, designed to convert 0- to 5-Vdc analog output voltage from high-line-pressure, low-differential-pressure standard to required frequency range. Enables selection of wider variety of high-accuracy pressure standards to enhance accuracy of measurement of ESP instrumentation while requiring little modification of manufacturer's system and no modification of operating software of system. Useful primarily in wind-tunnel instrumentation and readily adaptable to commercial instruments currently in use.
Voltage controlled, variable frequency relaxation oscillator with MOSFET variable current feed
As the semiconductor technologies progress rapidly, the power densities and switching frequencies of many power devices are improved. With the existing technology, high frequency power systems become possible. Use of such a system is advantageous in many aspects. A high frequency ac source is used as the direct input to an ac/ac pulse-density-modulation (PDM) converter. This converter is a new concept which employs zero voltage switching techniques. However, the development of this converter is still in its infancy stage. There are problems associated with this converter such as a high on-voltage drop, switching transients, and zero-crossing detecting. Considering these problems, the switching speed and power handling capabilities of the MOS-Controlled Thyristor (MCT) makes the device the most promising candidate for this application. A complete insight of component considerations for building an ac/ac PDM converter for a high frequency power system is addressed. A power device review is first presented. The ac/ac PDM converter requires switches that can conduct bi-directional current and block bi-directional voltage. These bi-directional switches can be constructed using existing power devices. Different bi-directional switches for the converter are investigated. Detailed experimental studies of the characteristics of the MCT under hard switching and zero-voltage switching are also presented. One disadvantage of an ac/ac converter is that turn-on and turn-off of the switches has to be completed instantaneously when the ac source is at zero voltage. Otherwise shoot-through current or voltage spikes can occur which can be hazardous to the devices. In order for the devices to switch softly in the safe operating area even under non-ideal cases, a unique snubber circuit is used in each bi-directional switch. Detailed theory and experimental results for circuits using these snubbers are presented. A current regulated ac/ac PDM converter built using MCT's and IGBT's is evaluated.
The results of calculations of the increase in losses in an induction motor with frequency control and different forms of the supply voltage are presented. The calculations were performed by an analytic method based on harmonic analysis of the supply voltage as well as numerical calculation of the electromagnetic processes by the finite-element method.