Series/Parallel Time-Multiplexed Switched-Capacitor Filters with Programmability Based on Non-Uniform Sampling

This paper presents an improved scheme for programmable time-multiplexed (TM) switched-capacitor (SC) filters. The proposed approach uses a novel sampling technique, which eliminates the need for resolution/area tradeoffs. The programmability of each processing channel is based on the use of non-uniform clock signals with noise-shaped sampling energy. No capacitor values are modified for programming frequency response parameters and, hence, the performance of the TM SC filter is not sacrificed for programmability. Such a sampling technique not only leads to an accurate frequency response control, but also allows the design procedures and the resulting SC circuit implementation to be simplified. A test-chip including a programmable second-order TM SC filter with a multiplexing order of four, which operates in series or in parallel mode, was fabricated in conventional CMOS technology. Measurement results demonstrate the effectiveness and versatility of the proposed technique.     

Analog neural programmable optimizers in CMOS VLSI technologies

Introduces a parallel switched-capacitor (SC) neural optimizer architecture and discusses area limitations due to the incorporation of programmability issues. Due to these limitations this architecture is only suitable for low dimension problems. A serial time-multiplexed architecture which allows digital control on the weight values with reasonable area figures is presented. A 3- mu m CMOS SC prototype demonstrating the concept of SC analog neural optimizers via an integrated circuit is discussed.<>     

Switched-capacitor biquad with low influence of finite gains

The letter describes a switched-capacitor (SC) biquad which exhibits less effect of the finite gains on the Q-factor and centre frequency than other known biquads of this type. The properties of the circuit have been established by extensive simulation studies using a symbolic analysis program.     

A 1-MHz Area-Efficient On-Chip Spectrum Analyzer for Analog Testing

This paper presents a 0.35-μm CMOS on-chip spectrum analyzer based on switched-capacitor (SC) techniques. The prototype device utilizes a 3-V supply and basically includes an SC sine-wave generator, a fourth-order high-selectivity SC filter, and a programmable gain amplifier followed by an 8-b analog-to-digital converter. A non-uniform sampling scheme, which adds one degree of freedom in determining the frequency response parameters of SC circuits, helps to obtain high programmability resolution without modifying any capacitor value. As a result, capacitor spread and total capacitor area are reduced as compared to traditional SC solutions and, hence, test area overhead is minimized. Experimental results demonstrate the effectiveness of the proposed approach to perform frequency response and total harmonic distortion measurements for frequencies up to 1 MHz.     

Programmable CMOS switched-capacitor biquad using quasi-passivealgorithmic DAC's

This paper describes an electrically programmable switched-capacitor (SC) biquad using quasi-passive algorithmic digital-to-analog converters (DAC's). Since only two equal-valued capacitors are needed for programming each capacitance value, the proposed technique offers compact, cost-effective programmability when compared to traditional programming techniques employing binary-weighted capacitor-arrays (C-arrays). A demonstration prototype chip realized in a 1.2 μm CMOS double-metal double-poly technology, and which implements an 8 b programmable SC biquad giving a wide range of lowpass, bandpass and highpass filtering functions, occupies an active area of only 0.38 mm²     

High-Selectivity Switched-Capacitor Bandpass Filter with Quasi-Continuous Quality Factor Tunability

This paper describes the design and implementation of a second-order switched-capacitor (SC) bandpass (BP) filter with very wide quality factor (Q) programmability range. The filter selectivity is digitally programmed by varying the effective sampling frequency of an SC branch, without modifying any capacitor value. The proposed approach allows a quasi-continuous Q-factor tunability avoiding, in principle, the inherent quantization error associated to any traditional programming technique. Automatic Q-factor tuning is performed by using a scheme based on an amplitude-locking loop approach. Experimental results obtained from a 0.8-m CMOS integrated prototype demonstrate the versatility of the proposed technique for high-Q SC BP filters.     

Quality factor measurement of micro gyroscope structure according to vacuum level and desired Q-factor range package method

A micro-machined gyro chip of gyroscope is normally packaged in specific vacuum level to get the specific quality factor(Q-factor). If the Q-factor is too high, frequency tuning and the approximate matching between driving and sensing comb structure become difficult, and if the Q-factor is too low, its sensitivity decreases. The optimum Q-factor of our gyro chip design is 4000 range. To get this range, we measured the drive mode Q-factor as vacuum level of our gyro chip and we found that the vacuum level of the desired Q-factor 4000 is in the range of 740 mTorr. Based on this data, we fabricate the wafer level package gyro chip of the desired Q-factor by controlled the basic pressure of package bonding chamber just prior to the bonding process. After wafer level package process, we measured Q-factor of whole samples. Among 804 samples, 502 packaged gyro chips are worked and the Q-factor of 67% samples is between 3500 and 4500 range.     

双层悬空结构射频微电感制作研究

利用MEMS工艺制作了一种双层悬空结构的圆形射频微电感,研究了双层结构微电感中微带线宽度对其性能的影响。研究表明,双层悬空结构的圆形射频微电感不仅具有较大的电感量,而且其Q值也较高;双层微电感的Q值随微带线宽度的增大而升高,而电感量则随微带线宽度的增大而降低。对于微带线宽度为60μm的双层微电感,在频率2～4GHz时,其电感量可达到5nH左右,Q值达到20。     

A Novel Method for Calculation of Eigenmodes of Gyrotron Resonators

A new method for calculating the eigenmodes of gyrotron resonators is presented. With this method, the resonant frequency, Q-factor and field profiles of the eigenmodes are determined through finding the minimum value of a function of two variables, namely the resonant frequency and the Q-factor. Compared with the traditional calculation method, the new method predicts a significantly higher Q-factor of the eigenmodes.     

Oscillatory-Plus-Transient Signal Decomposition Using TQWT and MCA

This paper describes a method for decomposing a signal into the sum of an oscillatory component and a transient component. The process uses the tunable Q-factor wavelet transform (TQWT): The oscillatory component is modeled as a signal that can be sparsely denoted by high Q-factor TQWT; similarly, the transient component is modeled as a piecewise smooth signal that can be sparsely denoted using low Q-factor TQWT. Since the low and high Q-factor TQWT has low coherence, the morphological component analysis (MCA) can effectively decompose the signal into oscillatory and transient components. The corresponding optimization problem of MCA is resolved by the split augmented Lagrangian shrinkage algorithm (SALSA). The applications of the proposed method to speech, electroencephalo-graph (EEG), and electrocardiograph (ECG) signals are included.     

W波段空间谐波磁控管π/2模品质因数的计算

谐振腔品质因数是描述磁控管特性的重要参数,本文分别采用线路法和场解法对W波段空间谐波磁控管π/2模品质因数进行计算,并与CST仿真结果进行了对比,验证了两种方法的正确性,这为W波段空间谐波磁控管π/2模品质因数的计算提供了理论依据。     

On the active compensation of noninverting integrators

A new active compensated balanced time constant (BTC) noninverting integrator is proposed. The compensation is achieved by using a voltage follower in the feedback path, and this result in an extremely high Q-factor, namely Q ≃ |A|³. It is also shown, that the use of a voltage follower with the Deboo noninverting integrator will only double its Q-factor. A novel method is proposed for active compensation of the Deboo integrator, which results in an extremely high Q-factor.     

The Tempest: a framework for safe, resource assured, programmablenetworks

Most research in network programmability has stressed the flexibility engendered by increasing the ability of users to configure network elements for their own purposes, without addressing the larger issues of how such advanced control systems can coexist both with each other and with more conventional ones. The Tempest framework presented here extends beyond the provision of simple network programmability to address these larger issues. In particular, we show how network programmability can be achieved without jeopardizing the integrity of the network as a whole, how network programmability fits in with existing networks, and how programmability can be offered at different levels of granularity. Our approach is based on the Tempest's ability to dynamically create virtual private networks over a switched transport architecture (e.g., an ATM network). Each VPN is assigned a set of network resources which can be controlled using either a well-known control system or a control system tailored to the specific needs of a distributed application. The first level of programmability in the Tempest is fairly coarse-grained: an entire virtual network can be programmed by a third party. At a finer level of granularity the Tempest allows user supplied code to be injected into parts of an operational virtual network, thus allowing application specific customization of network control. The article shows how the Tempest framework allows these new approaches to coexist with more conventional solutions     

The Island-Gate Varactor—A High-Q MOS Varactor for Millimeter-Wave Applications

A new accumulation MOS varactor with island-shaped poly gate layout is proposed to improve the quality factor ( Q-factor) at high frequency, which can be readily employed for CMOS-based millimeter-wave applications. Measured results up to 67 GHz show significant improvements in the Q-factor and the series resistance R_s over the conventional multi-finger MOS varactors with the same ground rule and gate area. The proposed island-gate MOS varactor is expected to improve the overall Q-factor of the LC tank of millimeter-wave oscillators.     

Comparison of system performance at 50, 62.5 and 100 GHz channel spacing over transoceanic distances at 40 Gbit/s channel rate using RZ-DPSK

Assuming RZ-DPSK format at 40 Gbit/s channel rate, the impact on the Q-factor of a variable channel spacing has been evaluated in five WDM experiments conducted in a recirculating loop over transoceanic distances. A degradation of the Q-factor by nearly 3 dB is observed when the channel spacing is reduced from 100 to 50 GHz     

Q-factor characterization of RF GaN-based metal-semiconductor-metal planar interdigitated varactor

We report the characterization of quality (Q)-factor of RF metal-semiconductor-metal (MSM) planar interdigitated varactors fabricated by standard AlGaN/GaN HEMT process. The MSM varactors have wide tuning range and exhibit high quality-factor at both the maximum and minimum capacitance values. The fundamental limitation of the Q-factor in the medium capacitance range is also revealed. The elimination of ohmic contact resistance in the MSM varactor configuration pushed up the peak Q-factor to 92 at 0.5 GHz and 41 at 1.1 GHz. The operation of the MSM varactor is modeled by a physical equivalent circuit, with which the dependence of the Q-factor over the entire tuning voltage range can be explained.     

Attenuation characteristics in confocal annular elliptic waveguidesand resonators

The perturbation method is used to obtain the attenuation constant and Q-factor of several TEM, TE, and TM modes in confocal annular elliptic waveguides (CAE-Ws) and confocal annular elliptic resonators (CAE-Rs). Normalized attenuation and Q-factor charts are given for a variety of possible combinations of the focal distance and the eccentricities. Comparisons between the first higher mode in a CAE-W and a coaxial waveguide with the same cutoff frequency and cross-sectional propagating area reveals a lower attenuation in elliptic geometry. Consequently, the Q-factor in a CAE-R is 20%-40% greater than a Q factor for a coaxial resonator with the same volume and resonant frequency     

可编程数据平面技术综述

在软件定义网络中,可编程数据平面提供的编程能力是网络功能虚拟化的基石。可编程数据平面技术的核心是可编程能力与数据包处理性能。首先从数据平面的可编程性出发,探讨现有数据平面的数据包处理抽象。然后,分别对数据平面实施的目标平台与对应平台上的主要流表算法进行介绍,详细论述现有数据平面技术。最后,探讨了高性能数据平面技术存在的关键挑战。     

一款应用于多频带的基于新型Cascode有源电感的高Q带通滤波器

设计了一款基于新型Cascode有源电感和有源负阻电路的二阶差分有源带通滤波器。新型有源电感和有源负阻电路的采用可实现在滤波器Q值不变的条件下对滤波器的中心频率进行调节。仿真结果表明,通过调节有源电感和有源负阻电路的偏置条件,可有效增大滤波器的Q值,且在保持Q值恒定在226的条件下中心频率的变化范围为0.2-3.7GHz。滤波器的以上特性使其能很好地应用于多频带的无线系统。