Buffer Stage Research Articles

Forward Body Biased Low Power 4.0-10.6 GHz Wideband Low Noise Amplifier

A forward body biased low power Low Noise Amplifier (LNA) is designed using Common Gate (CG) topology. By using current reuse technique between the first stage and second stage Common Source topology accompanied with forward body biasing leads to low power dissipation. A series to parallel tank circuit at this stage leads to wideband design. A shunt peaking inductor at the drain terminal of second stage causes the higher frequency peak to increase leading to wide bandwidth. Two CS cascade stages are used to increase the overall gain of the proposed LNA with a buffer stage at the output for output matching. The proposed LNA attained maximum gain of 26.39 dB with a gain greater than 16 dB over entire range. The circuit gives reflection coefficient less than – 10 dB with NF 2.7 dB. With Vdd of 0.925 V, a DC current of 8.32 mA is consumed giving 7.7 mW power consumption.

Analysis of plantar impact characteristics of walking in patients with flatfoot according to basic mechanical features and continuous wavelet transform

Flatfoot is a common foot deformity, and the collapse of the arch structure affects the foot cushioning during walking. A growing number of scholars have found that the analysis of the impact force should be combined with both the magnitude and the frequency of the impact force. Therefore, the aim of this study is to investigate the plantar impact characteristics of flatfoot patients and normal foot people at different load-bearing buffer stage from the time and frequency domains. Sixteen males with flatfoot and sixteen males with normal foot were recruited to walk on the plantar pressure test system at the same step speed, and the vertical ground reaction force data were collected from the heel contact stage and the arch support stage. The differences in the frequency domain of the ground reaction force between the flatfoot and the normal foot in the two stages were analyzed according to the basic mechanical characteristics and the continuous wavelet transform. Independent sample t-test was used to compare the baseline data of subjects, and the differences in foot impact force characteristics at different stages of foot type and weight-bearing cushion phase were compared by two-factor repeated measures Analysis of Variance. 1) In terms of basic mechanical characteristics, In both groups for flatfoot patients and normal foot people, the peak ground reaction force was higher in the arch support stage compared to the heel contact stage (Pflatfoot<0.001, Pnormal foot<0.001), and the load rate of force change was smaller in this stage (Pflatfoot<0.001, Pnormal foot<0.001). However, no differences in peak ground reaction force and time of occurrence were found between flatfoot and normal foot in the two stages (p > 0.05), in the arch support stage, the force change load rate of patients with flatfoot was lower than that of normal foot people (p = 0.021). 2) The results of time and frequency domain characteristics showed that during the heel contact and the arch support stage, no significant differences in the maximum signal power as well as the corresponding time and the frequency of the main impact force between the normal foot and the flatfoot were found. In both flatfoot and normal foot types, compared with the foot heel contact stage, the maximum signal power in the arch support stage was higher (Pflatfoot < 0.001, Pnormal foot<0.001), and the corresponding impact frequency was smaller (Pflatfoot = 0.002, Pnormal foot = 0.004). Once the step speed was controlled, the flatfoot patients only showed a smaller impact force load rate in the arch support stage, which may be related to their lower arch rigidity. The characteristics of the impact force in different stages of walking support period were different in time and frequency domain, suggesting that there may be differences in the function of various parts of the foot.

Land Use and Soil Type Exert Strongly Interactive Impacts on the pH Buffering Capacity of Acidic Soils in South China

Soil acidification is a severe environmental problem around the world. Soil pH buffering capacity (pHBC) is the intrinsic factor affecting the soil acidification rate and is intensively impacted by anthropogenic and natural conditions. However, composite assessments of the effects of land use and soil type on soil pHBC are still limited. Therefore, we collected samples of five soil types (red soil, lateritic red soil, latosol, paddy soil and acid sulphate soil) from two land use patterns of agricultural and adjacent forest fields at different depths (0–10 cm, 10–20 cm and 20–30 cm) in South China, aiming to investigate the effects of land use and soil type on soil pHBC in this region. The results show that land use, soil type and their interactions greatly influence soil pHBC and physico-chemical properties. Forest soils have a significantly higher pHBC (11.40–49.50 mmol·kg−1 soil·unit−1 pH), cation exchange capacity (CEC), exchangeable Al3+ (EAl3+) and clay content than agricultural soils. Acid sulphate soil has the highest pHBC (49.27–117.83 mmol·kg−1 soil·unit−1 pH) values and exchangeable acid (EA) content among all investigated soil types, whereas lateritic red soil has the lowest pHBC (10.56–31.71 mmol·kg−1 soil·unit−1 pH). In agricultural fields, soil pHBC is positively related to CEC, soil organic carbon (SOC) and EA, indicating that agricultural soils may be in a cation exchange buffering stage. The soil pHBC of forest fields is positively correlated with SOC and EAl3+, implying that forest soils may be in the Al buffering stage. In conclusion, soil pHBC would vary with different land use forms and soil types, in which a series of key complex physico-chemical processes and interactions would occur to regulate soil pH buffering capacity.

A Reference Source Circuit Design for Voltage Controlled Oscillator Chips

The basic principle and typical structure of the bandgap voltage reference source are introduced in detail in this paper. The performance index of the bandgap voltage reference is analyzed. The core circuit of a bandgap voltage reference source with good temperature characteristics and a high power supply rejection ratio (PSRR) is designed, in which a two-stage differential operational amplifier with a buffer stage is used, a start-up circuit without a capacitor is used to reduce the start-up time, and a common beta multiplication self-bias circuit is used to attenuate the effects of the power supply voltage. It is shown from the final HSPICE simulation results that the reference voltage temperature coefficient is approximately 7 ppm/°C within the range of -20 to 80°C in temperature, and the average PSRR can reach more than −56 dB within the range of 1 Hz to 10 kHz in frequency.

The Process of Soil Nutrient Stabilization in Micro-Patches in Alpine Kobresia Meadows

Micro-patches are the basic unit of grazing ecosystems; the characteristics of these micro-patches are relatively stable in species under different grazing intensities in the same vegetation, but obviously different in terms of the distribution pattern. This leads to differentiation of plant community numerical characteristics under different grazing intensities. Understanding the driving force of soil nutrient variation in micro-patches under grazing disturbances will help us comprehend the regulation strategy and adaptation mechanisms of the ecosystem against over-disturbance. We designed four scales: spatial (three typical micro-patches), temporal serial (6 years), a degradation succession process (four key degradation stages), and recovery treatment (three treatments: the original grazing intensity based on herder preferences, half of the original grazing intensity, and zero grazing). The soil nutrient characteristics used to estimate stabilization were the typical soil total nutrient content (soil organic matter [SOM], total nitrogen [TN], total carbon [TC], inorganic carbon [IC], total phosphorus [STP], total potassium [TK], and pH), and available soil nutrients (NH4+, NO3−, phosphorous [avP], and potassium [avK]). Variations in the SOM, TC, IC, TN, STP, avK, and NO3− levels in the main root distribution layers (0–20 cm) on the spatial scale were 69.8–79.7%, 61.4–80.35%, 49.8–79.58%, 60.52–76.34%, 46.44–89.89%, 45.5–71.36%, and 59.21–65.38%, respectively, which accounted for the largest variation in the four scales, based on multivariable analysis. The variations in the avP and NH4+ content of the main root distribution layers (0–20 cm) at the temporal scale were 46.42–67.93% and 48.11–64.55%, respectively, which accounted for the greatest variation in the four scales, based on a multivariable analysis. Upon comparing the degradation succession stages and recovery treatment in each stage, we found that the variation in avP, avK, STP, TN, TC, SOM, TC, and TN content was greater at the degradation succession scale than at the recovery treatment scale. The soil nutrient content of the micro-patches exhibited the smallest decrease in the Gramineae-Kobresia transformation (G-KP) micro-patch, followed by the Gramineae micro-patches (G) and Kobresia micro-patches (KP). The number of G micro-patches decreased with increasing grazing intensity whereas the number of KP micro-patches increased. When the number of KP micro-patches increased to a certain degree, the number of G-KP micro-patches then increased as well. G-KP micro-patches, characterized by cracking in the mattic epipedon in alpine meadows, increased with the grazing intensity increasing in a certain degree in K. pygmaea meadows with mattic epipedon cracking (CP); the latter buffered the nutrient variation and maintained the soil nutrients’ relative stability in the ecosystem. Thus, CP formed the buffer stage for maintaining self-stabilization during a regime shift and was considered the withstanding stage during the alpine Kobresia meadow degradation process.

Real-time measurement system for overlapping reflection signals of fiber Bragg gratings using high-speed wavelength-swept laser

We propose a real-time measurement system that prevents overlapping reflection signals in fiber Bragg gratings (FBGs). The system combines a wavelength-swept laser using Fourier domain mode-locking (FDML) and a buffer stage with three optical paths to obtain a high-speed measurement rate of 304.2 kHz. Systems using high-speed wavelength-swept lasers are affected by the propagation time (delay) of the optical fiber. The delay causes problems such as inaccurate measurements, difficulty in distinguishing FBG reflection signals, and overlapping FBG reflection signals. To prevent these problems, we introduce a method for pulse modulation of a wavelength-swept laser by a fiber switch. This method allows for correction of delays by extracting and identifying only the reflection signal of the FBG at a specific wavelength. By identifying the reflection signals of all FBGs, the overlapping signals can be determined. Accordingly, we devise a measurement method that uses a fiber switch to shade light in the wavelength region of one FBG with overlapping signals from the wavelength-swept light of the laser. This method suppresses overlapping and allows only the reflection signal of the other FBGs to be extracted and demodulated. The proposed system uses bidirectional forward and backward scans with the wavelength-swept laser, such that the shaded FBG signals can be demodulated with either scanning direction. We demonstrate that the system using a three-buffered FDML laser can simultaneously measure the strain or vibration of FBGs installed at arbitrary distances.

Performance Characterization of Form-Stable Carbon-based Network Microcapsules for Thermal Energy Storage

In order to solve the problems of easy leakage and low thermal conductivity of paraffin in molten state. In this study, modified phase-change microcapsules with paraffin as the core material, melamine-formaldehyde resin as the wall material, flake graphite (FG), multilayer graphene (GNP) and expanded graphite (EG) as heat conduction additives were prepared by in-situ polymerization. The results show that the thermal conductivity of the composite phase change material gradually increases with the increase of the mass fraction of carbon additives, and the heat transfer enhancement effect of EG/MPCMs composite phase change material is the most obvious, with a thermal conductivity of 1.9 W/(m⋅K), which is 9.5 times that of pure paraffin. The addition of FG/MPCMs, GNP/MPCMs and EG/MPCMs carbon-based materials have little effect on the latent heat of phase change microcapsules, and the latent heat retention rates are 83.8%, 78.8% and 86.4% respectively. Microcapsules with phase change have good leakage prevention performance, and there are two obvious temperature buffering stages in the process of melting and condensation, so which have good thermal regulation ability. Compared with the previous studies, the prepared composite phase change microcapsules have high thermal storage capacity while ensuring high thermal conductivity, and have potential applications in industry.

A 7.2-mW V-Band Frequency Doubler With 14% Total Efficiency in 130-nm SiGe BiCMOS

Low-voltage and low-power frequency multiplier blocks used in millimeter-wave RF frontends suffer from high conversion loss leading to lower overall efficiency. In this letter, an alternative approach in the design of a low-power <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}$ </tex-math></inline-formula> -band frequency doubler (FD) block without requiring an additional buffer stage is presented. The transconductance stage of a conventional Gilbert multiplier is replaced by a passive trifilar transformer serving as a power splitting, matching, and biasing network. The switching quad transistors are biased with the lowest possible dc current which still provides a positive conversion gain. Experimental results show that the circuit implemented in a 130-nm SiGe BiCMOS technology achieves 14% total efficiency at 58 GHz for an input power of 0 dBm while consuming only 7.2 mW of dc power. The measured saturated output power is 2 dBm and the measured fundamental rejection ratio (FRR) is 49 dBc. To the best of the authors’ knowledge, the lowest power consumption while maintaining a positive conversion gain among high FDs based on silicon is reported.

The Effect of Exercise Training on the Detection of Heart Rate and Body Temperature Sensors in Adolescents

The aim of this study is to study the effect of exercise training on heart rate and body temperature sensor detection in adolescents. For the methods of logical analysis, test, and mathematical statistics, this paper takes 60 students aged 13-15 in the experimental middle school as the research subjects to explore the characteristics of heart rate changes of middle school students under different high-intensity intermittent exercise schemes. Then, it analyzes the characteristics of heart rate change in exercise center and heart rate change in high-intensity intermittent exercise. The experimental results show that the high-intensity intermittent exercise of adolescents aged 13-15 presents the stage of rapid recovery and buffer recovery. Whether in the quiet heart rate buffer stage or the rapid heart rate increase stage, as well as the “extreme heart rate maintenance stage” and heart rate recovery stage, the heart rate change point of 15-year-old adolescents is 1-3 seconds later than that of 13-year-old and 14-year-old adolescents. In addition, in the heart rate maintenance stage of 15-year-old adolescents, the heart rate fluctuates greatly. The rapid recovery stage of boys is 1 minute, and the heart rate can reach the quiet heart rate after 4-5 minutes. The rapid recovery stage of girls is 1.5 minutes, and the heart rate can reach the quiet heart rate after 4-5 minutes. The older the age of high-intensity intermittent training of adolescents aged 13-15, the longer the rapid rise stage of heart rate change, and there was no significant change in quiet heart rate buffer stage and body temperature.

Design and Experimental Validation of a Shock-Absorption Mechanism Inspired From the Frog's Forelimbs

Frogs reveal superior shock-absorption ability, which is mainly brought by the forelimbs. Frogs touch the ground with their forelimbs first in landing, followed by the elbow joints’ compression. In this process, the muscles and tendons of the forelimbs are pulled to store energy. However, muscles and tendons reveal different characteristics in the buffering process. The shock-absorption principle of the frog's forelimbs should be discussed explicitly and systematically on the coordination of muscles and tendons. In this study, we compared the EMG signals of m. anconeus, a primary muscle of frog's forelimb for landing, with the dynamic motions of the forelimb in the landing process. A short muscle potential resting was found around the time of ground touching. Meanwhile, we found that after the frog's toes touched the ground, the movement of the frog went into a buffer stage to absorb impact energy, and the buffering process exhibited different stages, revealing linear and nonlinear characteristics. These results revealed that the forelimb muscles and tendons worked at different times in landing, which formed the different stages. Inspired by the buffering principle of the frog, a bionic shock-absorption mechanism was designed using the torsion springs and dampers. The newly designed mechanism revealed improved buffering performances than the traditional spring-damper devices.

Impact Analysis of Initial Cracks’ Angle on Fatigue Failure of Flange Shafts

A fatigue test on the failure mode of flange shafts was conducted. The propagation characteristics of the initial crack at the junction between the shaft and the flange as well as its angle effect were studied. This study developed an analysis program of fatigue crack propagation, based on the APDL (ANSYS Parametric Design Language). It obtained the effective angle interval within which the initial crack is able to propagate. The fitting calculation formula was derived and the results showed that: (1) The initial crack at the junction between the shaft and the flange would propagate in the radial and axial directions; the unstable crack propagation would cause an abrupt fracture of the cross-section, failing connection; and the angle of initial crack was uncertain. (2) The crack followed the I-II-III mixed mode, which was dominated by mode I. An initial crack with a larger angle showed more noticeable II-III characteristics; KII and KIII affected the crack’s propagation angle in the radial and axial directions and they also affected the structure’s surface direction. (3) The deepest point A of the crack was located at the junction between the shaft and the flange. Its crack propagation can be divided into three stages: rapid growth (stage 1), steady decline (stage 2, buffer stage), and instability (stage 3). The initial crack angle not only affected the propagation rate at stage 1 but also influenced the fatigue life distribution of the structure during propagation. The larger the initial crack angle was, the smaller the proportion of buffer stage in the total fatigue life would be. Moreover, the propagation of crack with a larger initial angle reached instability faster after stage 1, which would cause an abrupt fracture of the cross-section. This was unfavorable for deciding the crack detection time or carrying out maintenance and reinforcement. (4) The crack propagation at the junction between the shaft and the flange was determined by the size relation between ΔKI and ΔKth, instead of the effective stress intensity factor. The effective stress intensity factor can partly reflect the law of crack propagation, but cannot serve as the only criterion for crack propagation; it must be combined with the effective angle interval, which was negatively correlated with the crack’s shape ratio, to determine whether the crack would propagate.

Frequency Doubler Gate Drive Circuit Suitable for High-Frequency Applications

In megahertz (MHz) power converters, the gate drive loss becomes one of the main issues that should be addressed. In the relevant literature, several gate drive circuits had been proposed to reduce the gate drive losses. A literature survey is provided in the introduction section to summarize the merits and demerits of each circuit. These studies proposed innovative methods to reduce gate drive loss. Nonetheless, they did not propose any solution to reduce the loss of the buffer stage inside the drive IC. In this article, we present a frequency doubler gate drive circuit. The proposed gate drive circuit can double the frequency of the input PWM signal at the driver output stage, using the second harmonic of the input signal. Therefore, the loss of the buffer stage inside the drive IC can be significantly reduced, compared with the hard-switching, the inductive resonant, and multiresonant gate drive circuits. This article focuses on designing, simulating, and experimentally validating the frequency doubler gate drive circuit with a 6.78-MHz input frequency and 13.56-MHz driving frequency. The concept of a frequency tripler gate drive circuit is also introduced and discussed. For instance, the frequency tripler gate drive circuit can triple the frequency of the input PWM signal at the driver output stage using the third harmonic; in this scenario, a 20.34-MHz driving frequency can be obtained. The proposed frequency doubler gate drive circuit is experimentally tested in a 13.56-MHz class E inverter.

Low Noise Amplifier with Improved Gain and Reduced Noise-Figure in 90nm CMOS Technology

A CMOS low noise amplifier (LNA) for ultra-wideband (UWB) wireless applications is presented in this paper. The proposed CMOS low noise amplifier (LNA) is designed using common-gate (CG) topology as the first stage to achieve ultra-wideband input matching. The common-gate (CG) is cascaded with common- source (CS) topology with current-reused configuration to enhance the gain and noise figure (NF) performance of the LNA with low power. The Buffer stage is used as output matching network to improve the reflection coefficient. The proposed low noise amplifier (LNA) is implemented using CADENCE Virtuoso Analog and Digital Design Environment tool in 90nm CMOS technology. The LNA provides a forward voltage gain or power gain (S21) of 32.34dB , a minimum noise figure of 2dB, a reverse-isolation (S12) of less than - 38.74dB and an output reflection coefficient (S22) of less than -7.4dB for the entire ultra-wideband frequency range. The proposed LNA has an input reflection coefficient (S11) of less than -10dB for the ultra-wideband frequency range. It achieves input referred 1-dB compression point of 78.53dBm and input referred 3-dB compression point of 13dBm. It consumes only 24.226mW of power from a Vdd supply of 0.7V.

RETRACTED ARTICLE:Monsoon climate change based on cloud data and numerical simulation of basketball

Holocene is an important period for the evolution of human civilization and the study of the relationship between climate change and the development of human society. In the Asian monsoon region, monsoon climate change is an important factor affecting social culture and the change of historical dynasties. Therefore, the evolution of Holocene East Asian monsoon and the abrupt change of Millennium scale are the focus of scientific research. Holocene, as a typical interglacial period, is characterized by a series of abrupt climatic events on a millennium scale, such as Holocene rapid climate change (RCC) and high latitude bond events. In this paper, the quality of point cloud data and the quality of point cloud processing and rendering algorithm can be indirectly evaluated by evaluating the image quality of point cloud data directly drawn, so as to study the monsoon climate change. This paper also analyzes the origin of basketball, which originated in Massachusetts. It was invented by James Naismith, a Christian in Springfield, in 1891. It was introduced to China’s Tianjin YMCA in 1895. In 1896, the Tianjin YMCA held a basketball game performance. As a result, modern basketball officially began in China and gradually spread to the whole country extension. Basketball has been invented for more than 100 years. This paper analyzes and simulates the kinematic data of basketball players in the four stages of holding the ball preparation stage, kicking off stage, shooting in the air stage, and landing buffer stage, such as the movement time, joint angle change, and speed change. It promotes the improvement of basketball players’ shooting skills.

High-Speed Interrogation System for Fiber Bragg Gratings With Buffered Fourier Domain Mode-Locked Laser

We develop a high-speed interrogation system with a wavelength-swept laser for sensing multiplexed fiber Bragg gratings (FBGs). High-speed and multipoint sensing is achieved by means of a buffered Fourier domain mode-locked (FDML) laser, a recently proposed high-speed wavelength-swept laser. This laser increases the measurement rate several times by tailoring the laser output with a buffer stage. The developed buffered FDML laser successfully achieves a measurement rate of 202.8 kHz using a general FDML laser driven at a sweep rate of 50.7 kHz. In order to detect reflection signals of FBGs at the high measurement rate, the measurement system introduces digital signal processing using a field programmable gate array (FPGA). However, FBG measurements with wavelength-swept lasers are affected by the propagation time (delay) in the optical fiber connecting from the laser to the FBG sensor, which reduces measurement accuracy. To overcome this limitation, the developed system uses a delay correction method with bidirectional sweep of the buffered FDML laser. The interrogation system with the buffered FDML laser achieves a time resolution of 4.9 μs without being affected by the delay.

Design of Amplifier for Wearable Human ECG Sensor with Low Power and Low Noise

Electrocardiograph (ECG) data is an important index to determine the human heart state, which helps diagnose heart disease in an early stage. Since the ECG signal is instantaneous, it is important to make the ECG signal collector wearable and have good battery life. The wearable ECG devices need to have certain properties like interference suppression ability of acquired signal, low power consumption, low noise, and high integration, putting forward crucial requirements for the design of the amplifier. To meet the properties, the front-end analog processing circuit with interface input buffer stage structure and post-amp structure was proposed here, which has the characteristics of small size, low power consumption, low input referred noise, fair common-mode rejection ratio, and high input impedance. Besides, as one of the industrial-grade circuit simulation software, LTspice was used to design the circuit structure and analyze the corresponding performance. According to the circuit design and simulation testing, it turned out that the circuit in this work can be quite simple, and all the performance indexes met the practical demands. The frequency range was 0.1Hz∼100Hz, the voltage was 1.2V, the differential gain was 40.37dB, the total integrated input-referred noise was 3.48uVrms, and the total power consumption was 1.75uW. In summary, our data indicate that the ECG device we design is small enough to be wearable and has low power consumption.

A 148-GHz Radiator Using a Coupled Loop Oscillator With a Quad-Feed Antenna in 22-nm FD-SOI

This article presents a 148-GHz coupled loop fundamental oscillator with a quad-feed octagonal slot antenna. The proposed loop configuration with a multi-feed antenna leads to each oscillator experiencing multiple injected signals. An analysis is performed to explain the dynamics of the coupled loop oscillator in the presence of multiple signal-injection paths. It is shown that the proposed oscillator configuration will only operate with - π/2 phase between the adjacent oscillators. This phase difference is necessary for the quad-feed antenna to combine and radiate the output power from the four single-ended oscillators in the loop. The output from each oscillator is ac coupled to the following oscillator stage using a phase compensating capacitor, whose value is selected to enhance the oscillation frequency of the coupled loop. The use of buffer stages is avoided in favor of a passive power feed network for extraction of the output power from each oscillator. The proposed oscillator is fabricated in a 22-nm FDSOI process and has a 0.5-mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> chip area. The measured peak effective isotropic radiated power (EIRP) of the oscillator is 9.7 dBm with a corresponding dc-EIRP efficiency of 34.3% when operating from a 0.8-V supply. To the authors' knowledge, this dc-EIRP efficiency is the highest among reported oscillators to date operating between 100 and 200 GHz.

Comparison of active dual‐gate and passive mixers for terahertz applications

The authors propose four versions of a dual-gate active down-conversion mixer for H-band applications. The mixer operates at a local oscillator (LO) frequency of 240 GHz. It is designed for maximum conversion gain and a large bandwidth of at least 50 GHz from 220 to 270 GHz. Furthermore, the mixer is .optimised to operate at low LO power levels beneath 0 dBm. This renders power hungry LO buffer stages redundant. Hereby, the necessary chip size and the overall power consumption of fully integrated receivers can be drastically reduced. Four different versions of the downconverter were designed. Firstly, the layout of the transistors was changed from a conventional multi-transistor cell design to a mixer topology within the multi-finger transistor cell. Secondly, two on-chip solutions to decouple the drain voltage from the intermediate frequency (IF) signal were realised to facilitate zero-IF conversion: a resistive and an active load. The results are presented and the advantages and disadvantages of the four versions for the usage in terahertz applications are thoroughly analysed. Finally, the active dual-gate mixers are compared to a state-of-the-art resistive mixer for H-band with regard to conversion gain, bandwidth, linearity, noise figure and chip size.

Basketball Technology Simulation Application Based on Virtual Reality

The combination of virtual reality (VR) technology and basketball technology simulation can make the players have a real experience and experience, so as to effectively improve the quality of basketball training. It can also, according to the individual needs of different players, promote their physical and mental health development and improve the enthusiasm of basketball training, so as to improve the level of basketball technology. Immersive feeling and interest of human-computer interaction are the essential characteristics of virtual reality. The real conception of space-time environment, that is, the process of enlightening thinking and obtaining basketball technology simulation information, is the ultimate goal of virtual reality. In this experiment, five high-level basketball players in our city were selected and numbered from no. 1 to no. 5. Before the experiment, it is necessary to make the players warm up fully before the experiment and then test the forward turning technical movements of basketball. The test variables are based on different angles and distances. After that, standardized selection of basketball technical statistical indicators includes shooting hit rate, two-point hit rate, three-point hit rate, and free throw hit rate. According to the results of the experiment, it took the most time for the curve technique to lower the buffer stage, and it took up 29% of the total time of the entire precursor shot and turned back and the aerial shot stage is 23% and 22%, respectively. There is 20% time in the takeoff phase and 6% time in the brake phase. It has a great influence on the results of the game.

Electronic-Tuning-Facilitated Input Interface-Supported Load-Insensitive Filter with Extended Frequency Range

A new filter operating in voltage mode and realizing all-pass function is proposed. The circuit requires a single current conveyor with an extra voltage input buffer stage and a floating capacitor, enjoys electronic tuning, needs input interface for easy connection and benefits by low output impedance, hence is load-insensitive and operable at twice the frequency range in comparison to other related circuits. In-depth theoretical and simulation studies are presented in support of the newly designed circuit.