On the use of a digital computer as a two-phase variable-amplitudevariable-frequency oscillator

A feasibility study on the use of a digital computer as a variable-amplitude variable-frequency oscillator which generates two-phase sinusoidal excitation control signals for a dual-excited synchronous generator is described. The oscillator uses two input signals. One input signal is used to control the frequency of the oscillator outputs, and the other is used to control their amplitudes. By a single variable, the software can be configured to vary the oscillator frequency range and to greatly reduce (almost eliminate) the harmonic distortion of the output signals. The harmonic distortion is constant and independent of the output frequency for each possible oscillator frequency range. The software-based oscillator design is flexible and can be used to generate different types of multiphase signal waveforms     

复频率谐振子的偶奇相干态及其量子涨落计算

本文将复频谐振子量子化,提出了复频率谐振子的偶奇相干态概念;计算了复频率谐振子偶奇相干态下坐标、动量和能量的量子涨落;并对结果进行了讨论。结果表明,通常谐振子的上述结果对应于复频率谐振子的一种特殊情况。     

Stability of an Amorphous Silicon Oscillator

An RC oscillator using amorphous silicon thin film transistors was developed. The oscillation frequency and its dependence on resistance and bias voltage were studied. The frequency was controlled by adjusting the feedback resistance of the oscillator. The highest measured frequency of the oscillator was around 140 kHz, which is acceptable for low‐end radio frequency identification (RFID). Since a low‐end RFID circuit needs low cost and a simple process, an amorphous silicon oscillator is suitable.     

A Frequency Modulator with Gain for a Space Array

An active microwave frequency modulator is described which has been devised for a retrodirective space array. In this modulator one tunnel diode simultaneously functions as amplifier, frequency translator, and frequency modulator. The modulator is an image frequency converter with a local oscillator signal injected into the modulator circuit. The frequency of the image signal is modulated by varying the frequency of the local oscillator. The image frequency is the difference between the second harmonic of the local oscillator and the signal frequency. The frequency deviation of the image frequency signal is twice the frequency deviation of the local oscillator signal. Since the image frequency signal is the lower modulation side-band, its phase is inverted in reference to the phase of the incoming signal. The retrodirective characteristic of the modulated space antenna is realized by the phase inversion property of the modulator. Each array element is terminated with one modulator, and the local oscillator signals that are directed to the modulators must be of equal phase. No nonreciprocal device is required to separate incoming and reradiated signals in the antenna array. In order to determine the optimum operating conditions the analysis of the image frequency converter was derived and an experimental model was tested at 2 Gc. Amplification of the image frequency signal over the incoming signal of 27 db was obtained. The local oscillator power required by one modulator is 10 /spl mu/w; the dc bias power is less than 100 /spl mu/w.     

Micromechanical oscillator circuits: theory and analysis

In this paper, detailed theoretical analysis of micromechanical Transresistance oscillator is presented. Analytical expressions are derived for the frequency pulling, critical transimpedance, maximum negative resistance, and start-up time constant of the Transresistance oscillator circuit which are useful for the design of micromechanical oscillators. These results are then used to study the frequency stability of Transresistance oscillator circuit and compare its operating conditions with that of the Pierce oscillator circuit which is widely used in micromechanical oscillators. The results conclusively show that the Transresistance oscillator has less start-up problems and better frequency stability than the Pierce oscillator. These results are then verified with a well-established circuit theory that compares the phase-frequency plots of the Pierce and Transresistance oscillator.     

基于比时法的晶振频率测量建模与分析

受器件老化、随机噪声等因素影响,晶振频率变化较复杂。以GPS秒脉冲作为测量标准,构建了晶振频率随时间变化的测量系统,通过对测量数据进行一元回归统计处理,分离出了晶振实际频率与其标称频率的相对偏差及晶振的各种随机误差,并分析了这两种误差对晶振准确度及稳定度的影响。该方法可为频率源误差测量分析提供借鉴作用。     

一种频率稳定的改进型CMOS环形振荡器

在传统的环形振荡器基础上,提出了一种改进的ＣＭＯＳ环形振荡器。它克服了传统ＣＭＯＳ环形振荡器振荡频率随电源电压变化而严重不稳的缺点。通过仿真得到了电源电压与振荡频率的对应关系,取得了满意的结果。     

高频振荡器设计及其稳定度对比实验研究

设计了多型式的高频正弦波振荡器,对设计过程及注意事项作了阐述。对振荡器的稳定性研究作了实验设计,最后测试了振荡器的主要参数,通过比较实验及数据分析,总结几类常用振荡器的特点和稳定度特性,说明晶体振荡器具有较高的频率稳定度。     

射频MEMS封装振荡器的稳定性研究

文章介绍了一种由MEMS圆盘谐振器和低噪声反馈电路构成的射频振荡器。MEMS谐振器具备高Q值,使得振荡器表现出良好的频率稳定性和低相位噪声。采用低成本的金锡键合工艺对双端口谐振器封装后,进一步提升了频率稳定性。低噪声电路由两级放大组成,在提供足够增益的情况下,提升了相位噪声性能。之后测试得到的相位噪声分别是在1 kHz 频偏处为-96 dBc/Hz,噪底 -128 dBc/Hz 。中期稳定性和阿伦方差的测试结果分别为±4 ppm和10 ppb。这些结果均表明,该振荡器在新一代无线通信中有广阔的应用前景。     

Cross-coupled differential oscillator MMICs with low phase-noiseperformance

LC-tank oscillators in the 5~6 GHz frequency range have been designed and implemented in a commercial 0.6 μm GaAs MESFET technology. One is a voltage-controlled oscillator (VCO), and the other is an oscillator without a controlling element. The output frequency range of the VCO is from 5.44 to 6.14 GHz, and the measured phase-noise is -101.67 dBc/Hz at an offset frequency of 600 KHz from the 5.44 GHz carrier. The phase-noise of the 6.44 GHz oscillator is -108 dBc/Hz at an offset frequency of 600 KHz, and the phase-noise curve, in the offset frequency range between 100 KHz and 1 MHz, shows a -20 dB/decade slope. These phase-noise characteristics are comparable to, or better than, those of the reported 5~6 GHz-band CMOS oscillators. To our knowledge, this is the first GaAs MESFET-based oscillator which has a cross-coupled differential topology and a capacitive coupling feedback to suppress the up-conversion of 1/f noise. Also, it is first reported that the GaAs MESFET-based oscillator shows 1/f² phase-noise behavior across the offset frequency range from 100 KHz to 1 MHz     

Stabilization of Reflex Klystrons by High-Q External Cavities

The frequency stability of the local oscillator is often the most important factor in determining the IF bandwidth of superheterodyne receivers. The inherent frequency stability of the local oscillator, which in the case of millimeter reflex klystrons is quite poor, can be improved by electronic means with the use of some forms of microwave discriminator. An alternate method is to increase the effective Q of the oscillator, since the frequency stability of a free-running oscillator is proportional to the Q of the resonant circuit. The latter method has the advantages of simplicity and of ease of alignment and tuning. The frequency stability which results, while not as great as can be obtained electronically, is sufficient for some purposes.     

基于CMOS工艺的太赫兹振荡器

在太赫兹频段,无源器件电容电感的品质因数低、电路的寄生参数以及MOS管的截止频率影响使太赫兹振荡器电路难以实现高功率输出。提出一种300 GHz可调谐振荡器,首先,采用改进的交叉耦合双推(Push-Push)振荡器结构,通过输出功率叠加的方法输出二次谐波300 GHz信号,增加了振荡器的输出功率并突破了MOS管截止频率,并通过增加栅极互连电感增加输出功率。其次,太赫兹振荡器摒弃传统片上可变电容调谐的方式,通过调节MOS管衬底电压改变MOS管的栅极寄生电容实现频率调谐,避免太赫兹频段引入低Q值电容,进一步增加了输出功率。提出的太赫兹振荡器采用台积电40 nm CMOS工艺,基波工作频率为154.5 GHz,输出二次谐波为 309.0 GHz,输出功率可达-3.0 dBm,相位噪声为-79.5 dBc/Hz@1 MHz,功耗为28.6 mW,频率调谐范围为303.5~315.4 GHz。     

1.25厘米单调谐体效应振荡器

本文报导了一种单调谐体效应振荡器.该振荡器结构类似于Kurkoawa电路.但谐振腔采用H_(011)高Q圆柱腔.该振荡器电路负载变化对振荡频率影响较小,能够避免通常反射腔稳频振荡器受到负载变化可能出现跳频的缺点.而且噪声电平比其它振荡源要小.对电路参数经过适当选择后,振荡器的输出效率能达到40～60%,输出功率30～100mW.机械牵引带宽大于600MHz.该振荡器的主腔和调谐活塞采用线胀系数不同的材料进行温度补偿.当温度循环在-40℃至+70℃的范围内,频率温度系数一般优于0.08MHz/℃,功率稳定度优于0.022dB/℃.     

Frequency synthesiser architecture eliminating high speed frequency dividers for millimetre-wave applications

A frequency synthesiser architecture for millimetre-wave applications is proposed. The architecture is based on a triple-push oscillator, which functions both as a divider and oscillator. Thus, the proposed architecture eliminates the need for injection locked frequency dividers that are the main contributors to the limited tuning capability of millimetre- wave phase-locked loops. Since the proposed architecture is solely based on the performance of the triple-push oscillator, the measurement result of the first silicon triple-push oscillator at 30 GHz is presented to support the validity of the concept.     

基于锁相频率合成器的电压控制LC振荡器

详细描述了电压控制LC振荡器的设计思路、实现方法及指标测试。采用西勒振荡器作为振荡器的主体部分,通过改变变容二极管两端的电压来调节振荡器输出频率,实现输出频率在15MHz～35MHz范围内可变;采用集成锁相环芯片MC145152来提高振荡器输出频率的稳定度,使其达到10-5;通过AT89C51改变锁相环的分频比,实现频率步进为100kHz/1MHz的两种工作模式,并实时显示。     

“行波管-YIG振荡器”的讨论

本文分析了用钇铁柘榴石(YIG)电调滤波器作为外反馈元件的行波管振荡器的工作原理,推导了这种振荡器的调谐特性。分析表明这种振荡器可以在很宽的频率范围内振荡,但振荡频率是不连续的,每隔一定频率相继出现振荡区和停振区,在一般情况下振荡区和停振区约各占一半,理论分析与实验结果基本符合,这说明行波管-YIG振荡器用作一般的宽频带扫频振荡器还存在一定的问题。     

Class-E MOSFET tuned power oscillator design procedure

A complete design procedure of a Class-E oscillator for a duty cycle of 0.5 is presented. It is based on an analytical solution of equations, which describe oscillator operation for steady state. General equations for all oscillator component values are given. Using the proposed procedure, the components were calculated for an example oscillator. The oscillator was built and tested using an MTP3055E power MOSFET. The efficiency and output power versus frequency, and the oscillation frequency versus dc supply voltage were measured. At V/sub DD/=4.5 V, the measured oscillation frequency was 800 kHz, the output power was 0.953 W, and the efficiency was 82%.     

Integrated Tunable Cavity Gunn Oscillator for 60-GHz Operation in Image Line Waveguide

The design, construction, and experimental test results of a mechanically tunable Gunn oscillator using a recessed diode metal coaxial cavity coupled to an image line waveguide is described. The oscillator frequency was changed by about 10-percent by varying the bias post length into the coaxial structure. The oscillator is designed so that both the Gunn diode and resonant cavity can be quickly replaced to provide extended frequency coverage and efficiency. This Gunn diode oscillator has provided up to 15-mW CW power at 60 GHz with 10-percent tuning range.     

一种低电源电压灵敏度RC振荡器的设计

基于传统RC振荡器的理论分析,采用电阻串分压提供参考电压的方式,设计了一种低电源电压灵敏度的振荡器。基于HHNEC 0.5μm BiCMOS工艺,完成了HSPICE仿真。仿真结果显示,该振荡器输出一个频率为63kHz、占空比为50%的方波信号,当电源电压在4.5～5.5V之间变化时,频率变化范围在±0.52%内,有效降低了电源电压对振荡频率的影响。该振荡器可应用于开关电源芯片。     

锁相频率合成方式的VHF电视差转机本振系统

本文介绍了用锁相频率合成技术构成电视差转机本振系统的原理和设计,讨论了有关理论和实践问题。已研制成功的硬件系统表明,该系统频率稳定度高,具有与晶振相同的数量级,频道转换迅速、可程控,且结构简单,经济可靠,可替代传统方式的本振。