Electronically tunable voltage-mode universal filter with single-input five-output using simple OTAs

This article presents a new electronically tunable voltage-mode universal biquadratic filter with single-input five-output using simple operational transconductance amplifiers (OTAs) and grounded capacitors. The proposed configuration provides low-pass, band-pass, high-pass, band-stop and all-pass voltage responses at a high-impedance input terminal that enables easy cascading in voltage-mode. The natural frequency and the quality factor can be set orthogonally by adjusting the circuit components. The natural frequency can also be controlled electronically by adjusting the bias currents of the OTAs. For realising all the five standard filtering functions, no critical-matching conditions are imposed and all the incremental parameter sensitivities are low. Experimental and simulation results that confirm the theoretical predictions are given.     

Electronically tunable sinusoidal oscillator circuit with current and voltage outputs

A new circuit configuration for the realisation of an electronically tunable sinusoidal oscillator is presented. The proposed circuit uses only one current backward transconductance amplifier (CBTA), two grounded capacitors and one resistor. Using current controlled CBTA (CC-CBTA) instead of the CBTA, the resistor can be completely removed. It has also current-mode (CM) and voltage-mode (VM) outputs, simultaneously. The workability of the proposed structure has been demonstrated by both simulation and experimental results.     

Resistorless dual-mode quadrature sinusoidal oscillator using a single active building block

This paper presents a new realization of resistorless mixed-mode (i.e. both voltage-mode and current-mode) quadrature sinusoidal oscillator using a new active building block (ABB) called the differential voltage current-controlled conveyor transconductance amplifier (DVCCCTA). The proposed oscillator circuit uses a single DVCCCTA, two grounded capacitors (GCs) and does not employ any external linear resistors. The tuning laws for the condition of oscillation (CO) and the frequency of oscillation (FO) are non-interactive; and controlled by separate bias currents. The circuit provides two explicit quadrature current outputs and two quadrature voltage outputs and thus can be classified as a mixed-mode quadrature oscillator. Another notable feature of the proposed circuit is that it can also be used as a biquadratic filter to realize low-pass and band-pass filtering functions simultaneously. Non-ideal analysis of the circuit is provided and PSpice simulation results have been included to verify the workability of the proposed circuit.     

Current mode first order universal filter and multiphase sinusoidal oscillator

In this article a new current mode first order universal filter with single input and multiple outputs is proposed. The realization uses single dual-X multiple output second generation current conveyor (DX-MOCCII) and two passive grounded components. The presented circuit provides high-pass, low-pass and non-inverting and inverting all-pass responses simultaneously, all at different high impedance outputs. The realized circuit does not require any component matching constraint and all the sensitivities are found low. As an application the non-inverting all-pass filter is cascaded in a close loop with the current mode non-inverting integrator to design a current mode multiphase sinusoidal oscillator (MSO) having six phases. Voltage mode six phase sinusoidal oscillator is also achieved by resistively loading the current mode outputs. The analysis such as phase noise, non-ideality, stability and Monte Carlo are presented and discussed. The presented theory and its results are validated using 0.25 µm process parameters of TSMC in PSPICE simulator.     

Realization of electronically tunable voltage-mode/current-mode quadrature sinusoidal oscillator using ZC-CG-CDBA

This paper presents a first of its kind canonic realization of active RC (ARC) sinusoidal oscillator with non-interactive/independent tuning laws, which simultaneously provides buffered quadrature voltage outputs and explicit quadrature current outputs. The proposed circuit is created using a new active building block, namely the Z-copy controlled-gain current differencing buffered amplifier (ZC-CG-CDBA). The circuit uses three resistors and two grounded capacitors, and provides independent/non-interactive control of the condition of oscillation (CO) and the frequency of oscillation (FO) by means of different resistors. Other advantageous features of the circuit are the inherent electronic tunability of the FO via controlling current gains of the active elements and the suitability to be employed as a low-frequency oscillator. A non-ideal analysis of the circuit is carried out and experimental results verifying the workability of the proposed circuit are included.     

Single-input four-output voltage-mode universal filter using single DDCCTA

An electronically tunable universal voltage-mode biquadratic filter with single input and four outputs using one differential difference current conveyor transconductance amplifier (DDCCTA), two resistors and two grounded capacitors is proposed. All the five standard biquadratic filter functions; lowpass (LP), bandpass (BP), highpass (HP), bandstop (BS) and allpass (AP), can be obtained from the circuit configuration. The LP, BP and HP are simultaneously available without component matching condition. By imposing component choice, the BS and AP responses can also be realized from the same circuit configuration. In addition, the proposed circuit provides an electronic control of its natural angular frequency (ω₀) and quality factor (Q) by adjusting the bias current of the DDCCTA. The simulation results together with the ideal values are also given to demonstrate the performance of the proposed circuit.     

First-order allpass filter using multi-input OTA

A novel first-order allpass filter, operating in voltage-mode, is introduced in this article. Compared with the corresponding already proposed structures, attractive offered benefits are the capability for simultaneous offering a minimum number of active and passive components, and the absence of any realisability restriction. These have been achieved by employing a multiple-input operational transconductance amplifier as active element. The performance of the proposed circuits has been evaluated through simulation results, utilising the Analog Design Environment of Cadence software.     

Single MIMO-OTA and single-grounded-capacitor-based first-order allpass filter design

A novel first-order voltage-mode allpass (AP) filter employing a single multiple-input-multiple-output operational-transconductance-amplifier (MIMO-OTA) and a single grounded capacitor is introduced in this article. Compared to the corresponding already published topologies, the offered benefits are as follows: it employs minimum number of active and passive components; the only capacitor is grounded, which is good for a monolithic integration of an IC; and the absence of any matching condition for its realisability. The performance of the proposed circuit has been evaluated through simulation results, utilising the analogue design environment of Cadence software.     

New electronically tunable current-mode universal biquad filter using translinear current conveyors

In this study, a new electronically tunable current-mode universal filter with two inputs and two outputs employing one translinear current conveyor, one translinear current conveyor with controlled current gain and two grounded capacitors is presented. The proposed circuit offers the following attractive features: realisation of low-pass, band-pass, high-pass, band-stop and all-pass current responses from the same configuration; employment of the minimum active and passive components; no requirement of component matching conditions; independent current-control of the parameters natural frequency (ω_o) and quality factor (Q); low active and passive sensitivities; and high impedance output. The characteristics of the proposed circuit are simulated using PSPICE to confirm the theory.     

Multiple-input single-output low-input and high-output impedance current-mode biquadratic filter employing five modified CFTAs and only two grounded capacitors

This paper presents a novel current-mode biquadratic filter with three inputs and a single output. The proposed circuit employs five modified current follower transconductance amplifiers (MCFTAs) and only two grounded capacitors. It can realize all five biquadratic filter functions namely: low-pass (LP), band-pass (BP), high-pass (HP), band-stop (BS) and all-pass (AP) at the output terminal by selecting different input current signals, without requiring any parameter-matching conditions or additional circuits. The filter has an orthogonal electronic adjustment of the natural angular frequency ω₀ and the quality factor Q, and it has very low element sensitivities of ω₀ and Q. Moreover, the proposed filter has the feature of high output impedance and low input impedance, and the use of only grounded capacitors makes it convenient for integrated circuit implementation. The performances of the proposed circuit are illustrated by PSPICE simulations, and the results are in good agreement with theoretical analysis.     

CMOS realization of single-resistance-controlled and variable frequency dual-mode sinusoidal oscillators employing a single DVCCTA with all-grounded passive components

In this paper, two new designs are proposed for sinusoidal oscillators based on a single differential voltage current conveyor transconductance amplifier (DVCCTA). Each of the proposed circuits comprises a DVCCTA combined with passive components that simultaneously provides both voltage and current outputs. The first circuit is a DVCCTA-based single-resistance-controlled oscillator (SRCO) that provides independent control of the oscillation condition and oscillation frequency by using distinct circuit parameters. The second circuit is a DVCCTA-based variable frequency oscillator (VFO) that can provide independent control of the oscillation frequency by adjusting the bias current of the DVCCTA. In this paper, the DVCCTA and relevant formulations of the proposed oscillator circuits are first introduced, followed by the non-ideal effects, sensitivity analyses, frequency stability discussions, and design considerations. After using the 0.35-μm CMOS technology of the Taiwan Semiconductor Manufacturing Company (TSMC), the HSPICE simulation results confirmed the feasibility of the proposed oscillator circuits.     

两输入全差分高频宽线性可调的OTA及其滤波器应用

文章提出了一种采用两输入全差分结构、线性可调范围宽的高频跨导运算放大器，适合于需大范围连续调谐的高频连续时间滤波器。仿真结果表明，通过频率补偿，在高频情况下，它不仅具有良好的线性输入和线性可调范围，而且具有较好的频率响应特性，对高频滤波器的性能有一定的改善。     

Realization of current-mode biquadratic filter employing multiple output OTAs and MO-CCII

This paper presents a low voltage low power operational transconductance amplifier circuit. By using a source degeneration technique, the proposed realization powered at ±0.9 V shows a high DC gain of 63 dB with a unity gain frequency at 3.5 MHz, a wide dynamic range and a total harmonic distortion of −60 dB at 1 MHz for an input of 1 Vpp. According to the connection of negative current terminal to positive voltage terminal of double output OTA circuit, a second generation current conveyor (CCII-) has been realized. This circuit offers a good linearity over the dynamic range, an excellent accuracy and wide current mode of 56 MHz and voltage mode of 16.78 MHz cut-off frequency f-3 dB.Thereafter, new SIMO current-mode biquadratic filter composed by OTA and CCII as active elements and two grounded capacitors is implemented. This filter is characterized by (i) independent adjusting of pole frequency and quality factor, (ii) it can realize all simulations results without changing the circuit topology, (iii) it shows low power consumption about 0.24 mW. All simulations are performed by Cadence (Cadence Design Systems) technology Tower Jazz 0.18 μm TS18SL.     

Voltage difference transresistance amplifier and its application: floating FDNR simulator circuit

In this article, a new active building component with electronically tunable transresistive block, voltage difference transresistance amplifier, and its floating frequency dependent negative resistor simulator circuit application is presented. The simulator circuit is shown to operate using single active building block with two grounded passive components, to be electronically tunable over its value which is controlled by an independent current source, not to require any conditions of component matching and to have good sensitivity performance with respect to tracking errors. To examine functionality of the design, a CRD band-pass filter example is given.

Numerous simulation program with integrated circuit emphasis (SPICE) simulations are performed and depicted through the article to verify validity of the study. Taiwan semiconductor manufacturing company (TSMC) 0.18 µm complementary metal oxide semiconductor technology parameters are used through simulations.     

基于级联调制器和四波混频效应的24倍频微波信号的光学生成

提出了一种基于级联马赫-曾德尔调制器 (MZM)和半导体光放大器(SOA)的24倍频微波信号 光学生成方案,具有覆盖频段高、杂波抑制效果好等优点。在本方案中,低频微波信号分别 通过两个级联 MZM对连续光源进行调制,调节直流偏置使两个MZM均工作在最大偏置点,以抑制奇数阶光分 量;进一 步调节两个MZM的调制深度,并结合可调谐电相移器(TEPS)和可调谐光相移器(TOPS)引入相 移,完全抑 制第2个MZM输出的±2阶光分量和光载波,得到±4阶光分量;再经过SOA发生四波混频(FWM )效应,形成±12 阶光分量;滤波后拍频可以获得24倍频微波信号。最后,搭建了实验和仿真系统,分别以11．0GHz,11.5GHz和12.0GHz的微波信号为驱动,得到间隔为264、276GH z和288GHz的±12阶光边带,有效验证了方案的可行性。     

Implementation of a Communications Channelizer using FPGAs and RNS Arithmetic

Field-programmable logic (FPL), often grouped under the popular name field-programmable gate arrays (FPGA), are on the verge of revolutionizing sectors of digital signal processing (DSP) industry as programmable DSP microprocessor did nearly two decades ago. Historically, FPGAs were considered to be only a rapid prototyping and low-volume production technology. FPGAs are now attempting to move into the mainstream DSP as their density and performance envelope steadily improve. While evidence now supports the claim that FPGAs can accelerate selected low-end DSP applications (e.g., FIR filter), the technology remains limited in its ability to realize high-end DSP solutions. This is due primarily to systemic weaknesses in FPGA-facilitated arithmetic processing. It will be shown that in such cases, the residue number system (RNS) can become an enabling technology for realizing embedded high-end FPGA-centric DSP solutions. This thesis is developed in the context of a demonstrated RNS/FPGA synergy and the application of the new technology to communication signal processing.     

基于高阶累积量和多相滤波器联合处理的PRBC-LFM参数提取

针对传统算法在进行伪码-线性调频信号参数提取时存在的条件限制和在低信噪比下提取精度不高的问题,文章提出了一种利用多相滤波器组和高阶累积量相结合进行参数的提取方法,该方法能够完成伪码-线性调频信号（PRBC-LFM）参数在高斯噪声下的提取。首先通过多相滤波器组能快速完成信号在频域上的均匀划分,接着对子带信号进行三阶累积量的短时估计,从而达到了抑制高斯噪声和实现在低信噪比下进行信号参数的提取的目的。测试结果表明,在低信噪比下使用该方法进行参数估计时精度很高。