一种自动频率调谐高频跨导电容滤波器

采用BiCMOS工艺,设计了可自动频率调谐的高频跨导-电容滤波器.在跨导电路中,使用有源负阻稳定共模信号,提高直流增益.在频率调谐电路中,利用锁相回路比较参考频率与滤波器输出频率的相差,进而调节滤波器特性.     

A wide-band CMOS injection-locked ring oscillator

An injection-locked ring oscillator fabricated in a 0.18-/spl mu/m CMOS process is presented for high-speed applications. By tuning the free-running frequency, the proposed circuit provides 2:1 and 4:1 frequency division over a wide input frequency range. The measured input frequency range covers 16.7-25.2 GHz and 41.2-46.9 GHz for 2:1 and 4:1 frequency division, respectively. The divider core operates at a 1.8-V supply voltage with a power consumption between 21.0 and 23.8mW for the entire frequency tuning range.     

A high-linear wide-tunable CMOS transconductor for video frequency applications

In this paper a new CMOS transconductor structure based on a g_m-boosted degenerated differential pair is presented for applications in the video frequency range. The proposed circuit combines two techniques, a switchable array of source degenerating MOS resistors and a programmable output current mirror, in order to widen the G_m tuning range while maintaining linearity. Degeneration MOS resistors are made common-mode voltage independent thanks to a simple control circuit. Post-layout simulation results from a 0.35 μm design supplied at 3.3 V show a wide tuning range (10–100 MHz), good linearity (−58.4 dB for an output signal voltage of 1.1 V_p–p) and low excess phase (<0.5° over the whole tuning range).     

A Switchable-Order Gm-C Baseband Filter With Wide Digital Tuning for Configurable Radio Receivers

A master/slave technique which allows digital tuning of a G_m-C filter's cut-off frequency is proposed. It relies on an accurate transconductance division technique, fixing the reference frequency independently from the filter cut-off frequency. The design of a digitally-tunable G_m-C switchable third/fifth- order Butterworth low-pass filter in a 0.13-mum 1.2-V CMOS process is also proposed. An extended tuning range (above 25:1) is obtained through the design of a linear very widely tunable transconductor. Measured results prove this chip to be compatible with the baseband part of direct-conversion cellular receivers, from GSM to W-CDMA, with a tuning accuracy better than 5% over the entire tuning range.     

A novel pseudo differential transconductor for IEEE 802.11 WLANs

A novel pseudo differential transconductor for multi-mode analog baseband channel selection filter is presented. The highly linear transconductor is designed based on the dynamic source degeneration and predistortion cancellation technique. Meanwhile, wide tuning range is achieved with the current division technique. An LC ladder third-order Butterworth low-pass filter implemented with transconductors and capacitors was fabricated by TSMC 0.18-μm CMOS process. The results show that the filter can operate with the cutoff frequency ranging from 4 to 20 MHz. The tuning range is wide enough for the specifications of IEEE 802.11a/b/g/n Wireless LANs under the consideration of low power consumption and linearity requirement. The maximum power consumption is 3.61 mA at the cutoff frequency of 20 MHz.     

一种新型的ω_n和Q可编程MOSFET-C二阶滤波器

介绍一种新型的ωｎ和Ｑ可编程ＭＯＳＦＥＴ－Ｃ二阶滤波器的新技术。滤波器中的电阻全部用ＭＯＳＦＥＴ代替，构成压控电阻，对滤波器的中心频率ωｎ可通过改变栅极直流控制电压来调节，并且在滤波器的反馈路径中引入非线性电路，使滤波器对Ｑ和ωｎ在很宽范围内编程，而且没有相位误差。     

An electronically tunable current-mode quadrature oscillator using PCAs

This article presents a new realisation of active RC sinusoidal oscillator with electronically tunable condition and frequency of oscillation (FO). As compared to the class of three resistors, two capacitors (3R-2C)-based canonic oscillators, the circuit proposed here uses only two resistors and two capacitors as the passive components and still provides non-interactive tuning laws for the condition of oscillation and the FO. The proposed circuit employs new bipolar programmable current amplifier as the active building block and is capable of simultaneously providing two explicit quadrature current outputs. SPICE simulation results have been included to verify the workability of the circuit as an oscillator and the tuning range of the FO.     

用于低压差线性稳压器的输出精密微调设计技术

提出了一种用于低压差线性稳压器(LDO:Low-Dropout regulator)的输出精密微调方法,通过在反馈网络中引入可微调电阻梯实现对LDO输出的精密调整,并采取伪电阻保护的版图布局方式提高电阻梯的匹配性能。基于65 nm CMOS工艺对LDO进行了设计,整个LDO线性调整率约为0.05mV/V,输出电压在1.02V~1.36V范围内能够按照0.02V/step的最小步长进行精密微调,能有效减小由电源电压、温度等因素引起的输出误差,适合嵌入式片上系统(So C:System-on-Chip)的应用。     

Anti-blocker design techniques for MOSFET-C filters for directconversion receivers

A linearized MOSFET-C low-pass filter suitable for a baseband channel selection filter for a direct conversion receiver is presented. Using polysilicon resistors instead of MOSFET resistors in the input and output part, the filter achieves very high out-of-band linearity but maintains the original transfer function under the control of a continuous on-chip cutoff tuning scheme. In order to enhance the linearity of the triode-mode MOSFET variable resistors, the gates of the MOSFETs are driven by a charge pump in the cutoff control loop. Also, an appropriate gain scaling is implemented to lower the input referred noise, thus making the out-of-band dynamic range wider. This fifth-order elliptic filter achieves -2 dBV in-band IIP3, +28 dBV out-of-band IIP3, +94 dBV out-of-band IIP2 and -87 dBV input-referred noise, and dissipates 6.2 mW from a 2.7-V supply; the on-chip continuous automatic tuning system dissipates 4.1 mW     

R-MOSFET structure based on current division

A parallel-path combination of resistors and MOSFETs is proposed for use in integrated continuous-time filters and other circuits. The technique allows continuous incremental tuning while maintaining significantly better linearity than MOSFET-only structures.<>     

A gain stabilization technique for tuned RF low-noise amplifiers

A gain stabilization technique for tuned integrated low-noise amplifiers (LNAs) is presented. The proposed method regulates the LC-tuned load impedance of the amplifier at the operation frequency against variations of passive devices in integrated circuit (IC) process. The impedance stabilization technique is based on the excellent relative accuracy of integrated resistors. Although the absolute deviation of the integrated resistors can be as large as /spl plusmn/20%, the relative deviation can be made smaller than /spl plusmn/1% provided that resistors are placed close to each other. By applying the proposed method, the voltage-gain variation of the inductively degenerated common-source LNA, which is the most popular LNA architecture, can be reduced several decibels. As a consequence, the entire radio receiver can more easily meet its specifications in the presence of IC process variations and the product yield is improved. Finally, besides the LNAs, the presented stabilization technique can also be utilized in other tuned amplifiers, filters or oscillators employing damped LC-tuned loads.     

Economical line filtering for business communication systems

Economical active realizations of low-Q, all-pole, low-pass transfer functions are presented. The realizations allow a unidirectional sequence of functional tuning by trimming only resistors. Also, they have low sensitivities to the passive element variations. Experimental results verified the ease of tuning, the low sensitivity, and the low dependence on temperature and power supply variations.     

Novel active compensated weighted summer

A new active compensated generalised weighted summer is given. The compensation is achieved by using two extra operational amplifiers and six resistors. The proposed summer has negligible phase and magnitude errors over an extended frequency range. The design equations are given and the tuning procedure is discussed.     

A 3-V continuous-time filter with on-chip tuning for IS-95

This paper describes a low-voltage channel selection analog front end with continuous-time low-pass filters and on-chip tuning for a receiver in an IS-95 cellular phone. The filters were realized as balanced seventh-order elliptical g_mC filters to achieve low current consumption. The transconductors were realized by using second-generation current conveyors (CCII) and resistors to achieve good intermodulation distortion performance. A novel CCII circuit topology was developed to fulfil the low supply-voltage requirement. The cutoff frequency tuning was implemented with capacitance matrices and a time-domain master-slave tuning circuit     

Adjustable frequency dielectric resonator antenna

An easy method of tuning the resonant frequency of cylindrical and ring dielectric resonator (DR) antennas using different diameters of conducting plates is presented. This technique can tune a DR antenna to operate at the design frequency without changing antenna performance. The maximum frequency tuning range can reach up to 300-500 MHz     

A Novel Unequal Broadband Out‐of‐Phase Power Divider Using DSPSLs

In this paper, a novel unequal broadband out‐of‐phase power divider (PD) is presented. Double‐sided parallel‐strip lines (DSPSLs) are employed to achieve an out‐of‐phase response. Also, an asymmetric dual‐band matching structure with two external isolation resistors is utilized to obtain arbitrary unequal power division, in which the resistors are directly grounded for heat sinking. A through ground via (TGV), connecting the top and bottom sides of the DSPSLs, is used to short the isolation components. Additionally, this property can efficiently improve the broadband matching and isolation bandwidths. To investigate the proposed divider in detail, a set of design equations are derived based on the circuit theory and transmission line theory. The theoretical analysis shows that broadband responses can be obtained as proper frequency ratios are adopted. To verify the proposed concept, a sample divider with a power division of 2:1 is demonstrated. The measured results exhibit a broad bandwidth from 1.19 GHz to 2.19 GHz (59.2%) with a return loss better than 10 dB and port isolation of 18 dB.     

A CMOS bandpass filter for low-IF bluetooth receivers

A CMOS fully integrated 12th-order bandpass filter for low interemdiate frequency Bluetooth receivers is presented. The design is optimized to meet the selectivity and dynamic range requirements of Bluetooth while consuming relatively low power. The filter is based on unity gain cells and utilizes linearized MOSFET resistors for tuning. It exhibits a bandwidth of 1 MHz and a programmable center frequency range of 2 to 4 MHz. Experimental results obtained from a standard 0.5-/spl mu/m CMOS chip show that the filter exhibits an in-band dynamic range of 53.3 dB at gain of 0 dB, and 52 dB at gain of 15 dB, while consuming a total current of 1.32 mA. Attenuations of more than 10, 38, and 55 dB, are achieved for blockers one, two, and three, respectively.     

Optimization and implementation of multimode piezoelectric shuntdamping systems

Piezoelectric transducer (PZT) patches can be attached to a structure in order to reduce vibration. The PZT patches essentially convert vibrational mechanical energy into electrical energy. The electrical energy can be dissipated via an electrical impedance. Currently, impedance designs require experimental tuning of resistive circuit elements to provide optimal performance. A systematic method is presented for determining the resistance values by minimizing the H₂ norm of the damped system. After the design process, shunt circuits are normally implemented using discrete resistors, virtual inductors and Riordian gyrators. The difficulty in constructing the shunt circuits and achieving reasonable performance has been an ongoing and unaddressed problem in shunt damping. A new approach to implementing piezoelectric shunt circuits is presented. A synthetic impedance, consisting of a voltage controlled current source and a digital signal processor system, is used to synthesize the terminal impedance of a shunt network. A two-mode shunt circuit is designed and implemented for an experimental simply supported beam. The second and third structural modes of the beam are reduced in magnitude by 22 and 18 dB     

Low-voltage first-order fully differential CMOS all-pass filter with programmable pole-zero

A simple modification of the conventional first-order all-pass filter is introduced that provides it with a low-voltage fully differential operation with programmable pole-zero frequency. The modification is based on the inverting op-amp configuration and uses operational transconductance amplifiers instead of resistors not needing a buffered signal source or buffered op-amps as the conventional all-pass does. Experimental results verify that tuning capability is provided.     

瞬时频率指示器的频率校正

分析瞬时频率指示器的频率校正技术,着重介绍了相位的温度漂移的校正,借鉴传统的温度校码方法,提出一种以常温编码为基础,以编码移动和扩展为手段的低位扩展校正技术,彻底解决了相位的温度漂移造成的测频错误,同时大大地减少了调试的工作量。