P and M class phasor measurement unit algorithms using adaptive cascaded filters

The new standard C37.118.1 lays down strict performance limits for phasor measurement units (PMUs) under steady-state and dynamic conditions. Reference algorithms are also presented for the P (performance) and M (measurement) class PMUs. In this paper, the performance of these algorithms is analysed during some key signal scenarios, particularly those of off-nominal frequency, frequency ramps, and harmonic contamination. While it is found that total vector error (TVE) accuracy is relatively easy to achieve, the reference algorithm is not able to achieve a useful ROCOF (rate of change of frequency) accuracy. Instead, this paper presents alternative algorithms for P and M class PMUs which use adaptive filtering techniques in real time at up to 10 kHz sample rates, allowing consistent accuracy to be maintained across a ±33% frequency range. ROCOF errors can be reduced by factors of >40 for P class and >100 for M class devices

Filtering Technique for Stabilization of Marching-on-in-Time Method

In this paper, digital filters are used for the stabilization of the marching-on-in-time (MOT) method. A methodology of designing a proper filter using optimization techniques is proposed here. Since the proposed procedure considers the important part of the spectrum of the excitation signal, the designed filter does not degrade the accuracy of the MOT method. Further, the procedure for the efficient stabilization of the MOT method by a set of filters is proposed and verified on the examples

A wideband linear tunable CDTA and its application in field programmable analogue array

This document is the Accepted Manuscript version of the following article: Hu, Z., Wang, C., Sun, J. et al. ‘A wideband linear tunable CDTA and its application in field programmable analogue array’, Analog Integrated Circuits and Signal Processing, Vol. 88 (3): 465-483, September 2016. Under embargo. Embargo end date: 6 June 2017. The final publication is available at Springer via https://link.springer.com/article/10.1007%2Fs10470-016-0772-7 © Springer Science+Business Media New York 2016In this paper, a NMOS-based wideband low power and linear tunable transconductance current differencing transconductance amplifier (CDTA) is presented. Based on the NMOS CDTA, a novel simple and easily reconfigurable configurable analogue block (CAB) is designed. Moreover, using the novel CAB, a simple and versatile butterfly-shaped FPAA structure is introduced. The FPAA consists of six identical CABs, and it could realize six order current-mode low pass filter, second order current-mode universal filter, current-mode quadrature oscillator, current-mode multi-phase oscillator and current-mode multiplier for analog signal processing. The Cadence IC Design Tools 5.1.41 post-layout simulation and measurement results are included to confirm the theory.Peer reviewedFinal Accepted Versio

380 MHz Low-Power Sharp-Rejection Active-RC LPF for IEEE 802.15.4a UWB WPAN

This paper describes a wide-band sharp-rejection active-RC low pass filter (LPF) for pulse-based UWB IEEE 802.15.4a WPA, applications. Sharp rejection is attributed to the combination of different AC characteristic of three biquads in series. A simple operational amplifier (Op-amp) is adopted to ensure high frequency performance for the designed filter. The LPF is designed in 0.13μm TSMC CMOS process. The cutoff frequency is 380MHz with about 50% of the tuning range from 300-500MHz. The rejection is 40 dB at 600 MHz. The passband ripple is less than 1.5dB and the filter consumes 4.6mA from 1.2V supply. Core chip size is 580 x 700μm2

380 MHz Low-Power Sharp-Rejection Active-RC LPF for IEEE 802.15.4a UWB WPAN

This paper describes a wide-band sharp-rejection active-RC low pass filter (LPF) for pulse-based UWB IEEE 802.15.4a WPA, applications. Sharp rejection is attributed to the combination of different AC characteristic of three biquads in series. A simple operational amplifier (Op-amp) is adopted to ensure high frequency performance for the designed filter. The LPF is designed in 0.13μm TSMC CMOS process. The cutoff frequency is 380MHz with about 50% of the tuning range from 300-500MHz. The rejection is 40 dB at 600 MHz. The passband ripple is less than 1.5dB and the filter consumes 4.6mA from 1.2V supply. Core chip size is 580 x 700μm2

Improved IIR Low-Pass Smoothers and Differentiators with Tunable Delay

Regression analysis using orthogonal polynomials in the time domain is used to derive closed-form expressions for causal and non-causal filters with an infinite impulse response (IIR) and a maximally-flat magnitude and delay response. The phase response of the resulting low-order smoothers and differentiators, with low-pass characteristics, may be tuned to yield the desired delay in the pass band or for zero gain at the Nyquist frequency. The filter response is improved when the shape of the exponential weighting function is modified and discrete associated Laguerre polynomials are used in the analysis. As an illustrative example, the derivative filters are used to generate an optical-flow field and to detect moving ground targets, in real video data collected from an airborne platform with an electro-optic sensor.Comment: To appear in Proc. International Conference on Digital Image Computing: Techniques and Applications (DICTA), Adelaide, 23rd-25th Nov. 201

A Compact 1:4 Lossless T-Junction Power Divider Using Open Complementary Split Ring Resonator

This paper presents the size miniaturized and harmonic suppressed lossless 1:4 T-junction unequal power divider using an open complementary split ring resonator (OCSRR). By embedding the OCSRR structure in the microstrip transmission line, slow wave effect is introduced and thereby size reduction is achieved. The dimensions of OCSRR are optimized to reduce the length of high impedance and low impedance quarter-wavelength transmission lines. In our design high impedance line length is reduced to 58.6%, and low impedance line length is reduced to 12% when compared to the conventional quarter wavelength lines. The proposed power divider is having small dimensions of 0.18 λg × 0.33 λg and is 51.94% smaller than the conventional unequal power divider

Tunable Filter Design for the RF Section of a Smartphone

Skyworks Inc. has sponsored a WPI Major Qualifying Project involving the design of a tunable filter for the radio-frequency (RF) section of a smartphone. Our project involves designing and analyzing a single bandpass filter that can be tuned to various center frequencies. The band of frequencies that will be considered include frequencies in cellular band 25 (1850 MHz – 1955 MHz). The design realized in this project uses lumped element components configured in a capacitive coupled chebychev filter topology