Frequency Of Output Signal Research Articles

An 80–84.8 GHz PLL with auto-tracking Miller divider for FMCW applications

To generate high frequency signals for frequency modulated continuous wave (FMCW) application, components such as doubler, tripler or multiplier are usually utilized to process further signals from the low frequency voltage controlled oscillator (VCO). In this paper, a phase-locked loop (PLL) is intended to be the primary part used to generate frequency modulated continuous wave (FMCW) signals from 80 to 84.8 GHz by utilizing a fundamental frequency VCO. To divide those high frequency output signal and large output bandwidth, the auto-tracking Miller divider topology is proposed. This new topology can achieve 9 GHz locking range. In order to generate FMCW signals with a straight-line triangular chirp, the cascaded PLL is used. The integrated jitter from 1 kHz to 1 GHz is 887 fs for the cascaded PLL, while the single stage PLL used 1.264 ps. Moreover, when architecture with doubler or multiplier is used, the fundamental tone has an effect towards the next systems, while the cascaded PLL does not. It can be highlighted that this work achieves the best RMS-FMerror/BWchirp and RMS-FMerror/(BWchirp × fc × Tc) with value of 0.013% and 0.77e−12, respectively. The designed PLL for FMCW signal generator is implemented in 28 nm CMOS technology. By using a supply voltage of 1.2 V, the chip consumes power of 102 mW. Including all the chip pads, the implemented circuit occupies a silicon area of 1440 µm × 820 µm.

Terahertz-frequency oscillator driven by spin–orbit torque in NiF2/Pt bilayers

Exploration and manipulation of terahertz signal generators are crucial steps in the creation of numerous applications. Antiferromagnets can boost output signal frequency to the terahertz range. We propose a nanometer-scale generating device that produces terahertz signals by DC-exciting in a bilayer structure. The structure comprises a heavy metal layer (Pt) and a non-collinear antiferromagnetic layer (NiF2), where the magnetic moments in NiF2 with single-ion anisotropy are excited by the spin current from the Pt layer through spin–orbit torque. The inhomogeneous dynamic behaviors of the magnetic moments of NiF2 are calculated by the Landau–Lifshitz–Gilbert equation. It is found that terahertz-frequency AC can be reliably output from the bilayer structure, with the frequency that can reach to 1.82 terahertz. The oscillator shows the best performance when the polarized direction of the spin current is along the hard-axis of NiF2. The frequency and the amplitude of the AC can be adjusted by the current density, thickness and damping constant of the NiF2 layer. The threshold currents for exciting and maintaining the stable oscillation increase with the thickness and damping constant of the NiF2.

Control Strategy of Three-level Active Neutral Point Clamped Grid Connected Inverters in Unbalanced Power Grid

Traditional phase-locked loops in three-level active neutral point-clamped inverter grid-connected systems for photovoltaic power generation exhibit a deficiency in the decoupling of positive and negative sequences under unbalanced power grid conditions. To address this issue, this study proposes the implementation of the fourth-order generalized integrator into the phase-locked loop to facilitate positive and negative sequence decoupling. Initially, a 3L-ANPC inverter grid connection system is established. However, under unbalanced grid voltage conditions, the PLL effect of the Decoupled Double Synchronous Reference Frame Phase-Locked Loop is found to be suboptimal, leading to considerable fluctuations and distortions in the output frequency signal. To address these complications, we propose an optimized phase-locked loop structure. In this improved design, the PLL first utilizes the FOGI to filter out multiple harmonics in the grid voltage prior to decoupling the positive and negative sequence voltage. This process effectively mitigates the effect on the PLL, thereby enabling rapid and precise tracking of the grid voltage. Simulation analysis is conducted by using Matlab/Simulink to substantiate the effectiveness of the proposed PLL, demonstrating its ability to reliably lock onto the frequency and phase of the fundamental voltage under conditions of unbalanced power grid voltage.

Dynamic Control of the Efficiency of Mechanic Cutting of Material

Solution to the problem of improvement in the efficiency of material cutting equipment is an important task in the development of modern mechanical engineering and related areas of science and technology. Various material cutting methods are available at present: mechanical, hydromechanical (hydroabrasive), electrical discharge, plasma, laser, and others. Further improvement in the efficiency of the operation of material cutting equipment is related to the development of rapid methods and tools for monitoring the efficiency of cutting processes. The existing strain gauge means for monitoring the cutting power of materials are limited by the output signal frequency of up to 100 kHz. High-speed control of the efficiency of cutting processes can be carried out on the basis of the developed dynamic method and traditional controls of high-performance material processing equipment with an output signal frequency of up to 1 MHz.

Quartz crystal based sensor head design and analysis for robot torque sensor application

Background: Background: In recent years, with the gradual development of robot human-computer interaction, robots need to meet the precise control of more complex movements. Torque sensors play an important role. The traditional sensor uses metal strain gauge as the sensing element, which makes the sensor slow in response and low in resolution. In view of the shortcomings of strain gauge sensor, a sensor with cut quartz square as the sensing head is proposed. Methods: In order to study the quartz square sensitive head, COMSOL56 simulation modeling was first used to obtain the stress ratio relationship between the square quartz chip and the circular quartz chip. The formula for calculating the force frequency coefficient of the circular quartz chip was modified based on the ratio coefficient, and the formula for calculating the force frequency coefficient of the square quartz chip was obtained. The feasibility of the formula was verified through practical experiments; Secondly, theoretical simulation and experimental research were conducted on the buckling limit force of quartz chips, and the calculation formula for the buckling limit force during the installation process of quartz chips was revised, laying the foundation for the theoretical design of quartz sensors; Finally, the designed sensitive head is installed on the elastomer structure for verification; In order to collect frequency signals at a sampling rate of 1000Hz, the frequency signal output by the square quartz sensitive head is mixed, filtered, and amplified to form a 3.3V square wave between peaks. The frequency signal is collected by STM32. Conclusion: the test shows that the sensor with square quartz chip as the sensor head has a range of 150Nm, a sensitivity of 350 Hz / Nm, a linearity of 98.14%, a hysteresis of 0.51%, a repeatability of 98.44% and a resolution of 0.02%.

Transmission grating couples and enhances the second harmonic of the electron beam to generate tunable high-power terahertz radiation.

Vacuum electronic devices utilizing free-electron-based mechanisms are a crucial class of terahertz radiation sources that operate by modulating electron beams. In this study, we introduce what we believe is a novel approach to enhance the second harmonic of electron beams and substantially increase the output power at higher frequencies. Our method employs a planar grating for fundamental modulation and a transmission grating operating in the backward region to augment the harmonic coupling. The outcome is a high power output of the second harmonic signal. Contrasting with traditional linear electron beam harmonic devices, the proposed structure can achieve an output power increase of an order of magnitude. We have investigated this configuration computationally within the G-band. Our findings indicate that an electron beam density of 50 A/cm2 at 31.5 kV can produce a 0.202 THz center frequency signal with an output power of 4.59 W. As the electron beam voltage is adjusted from 23 kV to 38.5 kV, the output signal frequency shifts from 0.195 THz to 0.205 THz, generating several watts of power output. The starting oscillation current density at the center frequency point is 28 A/cm2, which is significantly lower in the G-band compared to conventional electron devices. This reduced current density has substantial implications for the advancement of terahertz vacuum devices.

Tunable multi-outlet single photon quantum router in an optomechanical system

An experimentally accessible tunable single-photon multi-channel quantum router is investigated in a system consisting of an optomechanics cavity coulomb coupling to a nano-mechanical resonator. The router can extract a single-photon from the coherent input signal directly modulate into three different output channels, and the output probability is all close to 1. More important, the two output signal frequencies can be selected by adjusting Coulomb coupling strength. We also demonstrate the vacuum and thermal noise will be insignificant for the optical performance of the single-photon router at temperature of the order of 20 mK. Our proposal may have paved a new avenue towards multi-channel router and quantum network.

SELF-OSCILLATING PARAMETRIC HUMIDITY SENSOR WITH FREQUENCY OUTPUT SIGNAL

A self-oscillating parametric humidity sensor has been developed that implements the principle of "humidity-frequency" conversion into hybrid integrated circuit based on a microelectronic transistor structure with a negative differential resistance, in which the humidity-sensitive element is a resistor of the HR202 type. For the purposes of determining parameters self-oscillating parametric humidity sensor with frequency output a mathematical model has been developed that takes into account the effect of humidity on a sensitive resistive element, which is an integral element of the device. Based on the mathematical model, analytical expressions for the transformation function and the sensitivity equation are obtained. It is shown that the main contribution to the conversion function is made by relative humidity. The computer simulation and experimental studies of a self-oscillating parametric humidity sensor with a frequency output signal contributed to obtaining the main parameters and characteristics, such as the dependence of the generation frequency on changes in relative humidity in the range from 30% to 99%, the change in sensitivity on relative humidity, the dependence of the active and reactive components of the impedance in the frequency range from 50 kHz to 2 GHz; standing wave ratio, change in logarithmic magnitude and spectra of the output signal of a parametric humidity sensor with a frequency output signal in the LTE-800 Downlink frequency range. The obtained electrical characteristics confirm the operability of the developed device. The sensitivity of the developed self-oscillating parametric humidity sensor in the range of relative humidity change from 30% to 99% has a value from 332.8 kHz/% to 130.2 kHz/%.

Simulation and Analysis of an FMCW Radar against the UWB EMP Coupling Responses on the Wires

An ultra-wideband electromagnetic pulse (UWB EMP) can be coupled to an FMCW system through metal wires, causing electronic equipment disturbance or damage. In this paper, a hybrid model is proposed to carry out the interference analysis of UWB EMP coupling responses on the wires to the FMCW radar. First, a field simulation model of the radar is constructed and the wire coupling responses are calculated. Then, the responses are injected into an FMCW circuit model via data format modification. Finally, we use the FFT transform to identify the spectral peak of the intermediate frequency (IF) output signal, which corresponds to the radar’s detection range. The simulation results show that the type of metal wire has the greatest influence on the amplitude of coupling responses. The spectral peak of the IF output changes to the wrong frequency with the increase of injection power. Applying interference at the end of the circuit can more effectively interfere with the detection of the radar. The investigation provides a theoretical basis for the electromagnetic protection design of the radar.

Mathematical model of a frequency pressure transducer based on a resonant tunneling diode

The paper presents the design of pressure sensor with a frequency output signal that is based on the physical processes in a resonant tunnel diode under the action of pressure. The use of devices with negative differential resistance can significantly simplify the design of pressure sensors in the entire radio frequency range. Depending on the operating modes of the sensor, an output signal can be obtained in the form of harmonic oscillations. Pressure sensor characteristics researches based on complete equivalent circuit diagram resonant tunnel diode, which takes into account its capacitive and inductive properties. A mathematical model of the pressure sensor was developed, upon which the analytical dependences of the change in the elements tunnel resonance diode from pressure have been determined, as well as conversion functions and sensor sensitivity. It is shown that the main contribution to changes in the conversion function and sensor sensitivity is made by the change in the negative differential resistance with the change in pressure. This, in turn, results in different readings of the instrument's output frequency. The sensitivity of the sensor varied from 1.15 kHz/Pa·105 to 14.16 kHz/Pa·105 in the pressure range from 50·105 Pa up to 350·105 Pa.

Chen system-based chaotic transceiver for frequency output quartz transducers

The application of unidirectional synchronization of two coupled Chen systems is exhibited in this work. In spite of the high dependence on initial conditions, which means that two initially close phase trajectories with time become uncorrelated, it is possible to synchronize two dynamic systems to make them evolve identically. Data transmission using chaos requires mixing an information signal with a chaotic carrier. This procedure performs data encryption and spreads the spectrum of an information signal, which increases information security and reliability. Thus, the prospect of using devices with chaotic dynamics in modern telecommunication and telemetry applications is due to several factors, including high information capacity, various frequencies, and confidentiality of messages. The proposed scheme is considered to be used in a measuring transducer design that requires sensors to operate at a long distance from the rest of the scheme. We propose an application of a chaotic oscillator as a transceiver module for a quarts sensor transducer, which could be used in a telemetry application. The process of producing non-periodic but determined oscillations by the non-linear Chen system and signal transmission application, based on it, are the subject of the research. The complete synchronization of two unidirectionally connected Chen systems and its signal transmission application are considered. The goal is to develop a transceiver extension for the quartz measuring transducer scheme to ensure the stable operation of sensors at a long distance from the rest of the scheme. The result of the research: a chaos synchronization scheme was applied to transmit a frequency-modulated signal, obtained from a difference-frequency block of the quartz sensor transducer. Additionally, the mathematical model and numerical modeling of the Chen dynamical system has been done. The numerical solution of the system's differential equations was obtained using Matlab software. To study the change in the dynamic regime depending on the parameters of the model, the spectrum of Lyapunov exponents was calculated and bifurcation diagrams were constructed. The circuit design of the Chen oscillator was built using Multisim software, which uses the PSpice model to simulate electrical components. A model of an analog signal transmission system with chaotic mixing of a frequency output signal with a chaotic carrier has been proposed as an extension of the use of quartz transducers in measuring devices.

AUTOGENERATOR PARAMETRIC SENSORS OF THE MAGNETIC FIELD WITH A HALL ELEMENT AND A TWO-COLLECTOR BIPOLAR MAGNETOTRANSISTOR

Self-oscillating parametric magnetic field sensors with a frequency output signal based on transistor structures with negative differential resistance with primary magnetically sensitive Hall elements and a bipolar two-collector magnetically sensitive transistor are proposed, moreover, the primary magnetically sensitive elements also act as active circuit elements. Magnetic field sensors with a frequency output do not require analog-to-digital converters and amplifying devices for further processing of information signals, which reduces the cost of information-measuring equipment, in addition, it is possible to transmit information over a distance when the sensors operate at microwave frequencies. Based on the analysis of physical processes in primary magnetically sensitive elements and self-oscillators, mathematical models of sensors were developed, on the basis of which parametric dependences of the conversion and sensitivity functions were obtained. The obtained functions clearly show the influence of each element of the primary magnetic converters and self-oscillator elements on the output frequency of the sensors in comparison with the calculations of the conversion functions from equivalent device circuits based on the Kirchhoff solution equations. It is shown that the main contribution to the conversion functions is made by a change in the magnetic induction, which causes a change in the negative differential resistance and the equivalent capacitance of the oscillatory circuit of the self-oscillator, which in turn changes the output frequency of the magnetic field sensors. Self-oscillating parametric magnetic field sensors with a frequency output signal can significantly improve the accuracy and sensitivity of measuring magnetic induction, abandon analog-to-digital converters and amplifying devices in the further processing of information signals, they also allow transmitting initial information over a distance when operating at microwave frequencies. The sensitivity of the magnetic field sensors varies from 1.45 kHz/mT to 11.95 kHz/mT when the magnetic induction changes from 0.1 to 120 mT.

Simulation of acoustic effects of postural laryngeal oscillatory movement during vocalization

This paper addresses the contributions of low-frequency postural laryngeal kinematics to frequency and amplitude modulations of the vocal output signal. A one-dimensional Navier–Stokes solution for fluid transport and wave propagation is used along with a laryngeal source model to simulate voice production. Vocal fold adduction and vertical laryngeal posture are modulated sinusoidally at 2–10 Hz with various amplitudes to approximate kinematic phenomena observed with MRI during production of vocal vibrato and voice tremor. The acoustic modulations are quantified in terms of formant (resonance) and fundamental frequency shifts in the radiated output signal from the mouth. Postural oscillation of the larynx is a common kinematic component of vocal tremor, although less documented during production of vibrato.

Design of a Variable Frequency and Energy Aeroengine Ignition Device Based on MCU

That the aeroengine ignition device’s ignition properties are set as a rule of thumb causes the waste of ignition device’s resources, low efficiency of aeroengine’s operation, and short service life of plugs. In this paper, a variable frequency and energy aeroengine ignition device is developed for improving aeroengine combustion chamber’s ignition properties. The STC89C52 MCU was chosen as the device’s core controller. Power supply circuit, MCU and external circuit, IGBT drive circuit, boost circuit, current-voltage monitor circuit, and discharge circuit are all part of the hardware circuit. Because the MCU is in charge of driving the IGBT and discharging the capacitor, the device can accurately generate a corresponding frequency output signal. It also creates frequency control and energy control modules, both of which can adjust ignition properties according to user needs. The ignition device proposed in this paper is stable and lighter and has a predetermined frequency and energy. It lays the groundwork for improving the aeroengine's ignition reliability.

Design and Implementation of Charge Pump Phase-Locked Loop Frequency Source Based on GaAs pHEMT Process.

This paper realized a charge pump phase locked loop (CPPLL) frequency source circuit based on 0.15 μm Win GaAs pHEMT process. In this paper, an improved fully differential edge-triggered frequency discriminator (PFD) and an improved differential structure charge pump (CP) are proposed respectively. In addition, a low noise voltage-controlled oscillator (VCO) and a static 64:1 frequency divider is realized. Finally, the phase locked loop (PLL) is realized by cascading each module. Measurement results show that the output signal frequency of the proposed CPPLL is 3.584 GHz–4.021 GHz, the phase noise at the frequency offset of 1 MHz is −117.82 dBc/Hz, and the maximum output power is 4.34 dBm. The chip area is 2701 μm × 3381 μm, and the power consumption is 181 mw.

Вопросы формирования зондирующего сигнала орбитального радиовысотомера

The accuracy of the formation of sounding signals of quasi-continuous radars is determined by the requirements for the permissible instrumental component of the error in measuring of the distance and Doppler frequency shift. High-precision orbital radio altimeters, as a rule, use precision signals with linear frequency modulation (chirp signals) as sounding signals, the linearity characteristics of which are quite demanding, since deviations from the linear law of change in the frequency of the radio altimeter sounding signal cause additional measurement errors. To reduce the instrumental error of the radio altimeter, it is necessary to improve the quality of the formation of the probing chirp signal, which can be ensured by forming them digitally. To assess the possibility of using a synthesizer based on the 1508PL8T microcircuit as a generator of the probing signal of a radio altimeter, measurements of the frequency modulation linearity were performed. The linearity of the modulation was estimated by the deviation of the instantaneous phase of the synthesized signal from the quadratic dependence. Studies have shown that fast fluctuations of the chirp signal frequency are significantly influenced by the time it takes the synthesizer to change the rate of rise of the signal phase. The selection of the parameters of the synthesized signals and the characteristics of the filters at the output of the digital-to-analog converters made it possible to reduce the formation error to 2.9·10−3 rad (RMS). When choosing the type of integrated synthesizer, it is necessary to focus on microcircuits with a high DAC clock frequency (above 1 GHz) and a short time spent on changing the output signal frequency (no more than 4 clock periods).

High linearity AlGaN/GaN HEMT with double-V th coupling for millimeter-wave applications

We demonstrated an AlGaN/GaN high electron mobility transistor (HEMT) namely double-V th coupling HEMT (DVC-HEMT) fabricated by connecting different threshold voltage (V th) values including the slant recess element and planar element in parallel along the gate width with N2O plasma treatment on the gate region. The comparative studies of DVC-HEMT and Fin-like HEMT fabricated on the same wafer show significantly improved linearity of transconductance (G m) and radio frequency (RF) output signal characteristics in DVC-HEMT. The fabricated device shows the transconductance plateau larger than 7 V, which yields a flattened f T/f max-gate bias dependence. At the operating frequency of 30 GHz, the peak power-added efficiency (PAE) of 41% accompanied by the power density (P out) of 5.3 W/mm. Furthermore, the proposed architecture also features an exceptional linearity performance with 1-dB compression point (P 1 dB) of 28 dBm, whereas that of the Fin-like HEMT is 25.2 dBm. The device demonstrated in this article has great potential to be a new paradigm for millimeter-wave application where high linearity is essential.

AlGaInP optical source integrated with fiber links and silicon avalanche photo detectors in fiber optic systems

This study has clarified aluminium gallium indium phosphide (AlGaInP) optical source integrated with fiber links and silicon avalanche photodetectors in fiber optic systems. The output spectral power, rise time, signal frequency and resonance frequency for AlGaInP laser diode. The laser diode rise time, output spectral power and resonance/signal frequencies versus injection current and ambient temperatures are sketched. The silica doped germanium fiber link pulse broadening and the signal fiber bandwidth are investigated against temperature variations. The signal per noise ratio is related to Q value and bit error rate (BER) at the receiving point (Si avalanche photodetector (APD)) are sketched with temperature.

Research on DDS-based Portable Signal Generation Testing Device

The signal generator has a wide range of applications in the fields of communication, measurement and control, navigation, radar, and medical treatment. At present, most of the signal generators in the laboratory are purchased precision instruments, which are not only expensive, but also can not fully perform their functions, resulting in a waste of resources [1]. Based on the analysis of the working principle of the existing signal generator, this paper takes the programmable DDS integrated chip as the core, and designs a sine wave and square wave signal generator that is simple in structure, high in accuracy, small in size, and suitable for laboratory requirements. The precision and error analysis are carried out on it. The signal generator is composed of a power supply system, a single-chip computer system, a DDS waveform generation module, an amplitude adjustment module, a square wave generation module, and a relay output module. A multiplier is used to multiply the sine signal and the analog signal of the single-chip microcomputer to achieve the purpose of amplitude modulation of the waveform. Compared with the general signal source, the signal generator has the advantages of small output signal frequency error, high resolution, full digital realization, easy integration, small size, light weight, convenient use, stable work, etc.

ДОСЛІДЖЕННЯ СЕНСОРА ТЕМПЕРАТУРИ З ЧАСТОТНИМ ВИХОДОМ НА ОСНОВІ КВАНТОВОЇ ГЕТЕРОСТРУКТУРИ З ВІД’ЄМНИМ ДИФЕРЕНЦІЙНИМ ОПОРОМ

Physical processes in a quantum two-barrier heterostructure, which is the basis for the development of tunnel-resonant diodes, are considered. These studies have shown that tunnel resonance diodes can be used as temperature sensors with a frequency output signal. The use of devices with negative differential resistance makes it possible to significantly simplify the design of temperature sensors in the entire radio frequency range, at which, depending on the operating modes of the sensor, an output signal can be obtained both in the form of harmonic oscillations and in the form of impulse oscillations of a special form. The study of the characteristics of the sensor is based on the equivalent circuit of the tunnel-resonant diode, which takes into account its capacitive and inductive properties. The current-voltage characteristic of the sensor has a falling section, which is responsible for the appearance of a negative differential resistance in this section. The descending section arises due to a decrease in the current that flows through the double-barrier quantum heterostructure, with an increase in voltage. A decrease in the current occurs due to a decrease in the transparency coefficient of the potential barriers of the heterostructure. A mathematical model of the temperature sensor has been developed, on the basis of which the analytical dependences of the change in the elements of the equivalent circuit of the sensor on temperature, as well as the transformation function and sensitivity, have been determined. It is shown that the main contribution to changes in the conversion function and sensor sensitivity is made by the change in the negative differential resistance with a change in temperature. This, in turn, results in different readings of the instrument’s output frequency. The sensor sensitivity was varied from 480 kHz/0С to 220 kHz/0С in the temperature range from -150 0С to 50 0С.