P-class phasor measurement unit algorithms using adaptive filtering to enhance accuracy at off-nominal frequencies

While the present standard C.37.118-2005 for Phasor Measurement Units (PMUs) requires testing only at steady-state conditions, proposed new versions of the standard require much more stringent testing, involving frequency ramps and off-nominal frequency testing. This paper presents two new algorithms for “P Class” PMUs which enable performance at off-nominal frequencies to be retained at levels comparable to the performance for nominal frequency input. The performances of the algorithms are compared to the “Basic” Synchrophasor Estimation Model described in the new standard. The proposed algorithms show a much better performance than the “Basic” algorithm, particularly in the measurements of frequency and rate-of-change-of-frequency at off-nominal frequencies and in the presence of unbalance and harmonics

Coarse wavelength division multiplexer on silicon-on-insulator for 100 GbE

A four-channel cascaded MZl based de-multiplexer at O-band with coarse channel spacing of 20 nm and band flatness of 13 nm is demonstrated on silicon-on-insulator. The device shows a mean crosstalk and insertion loss below -16 dB and 2.5 dB

On arbitrary-level IIR and FIR filters

A recently published method for designing IIR (infinite-impulse-response) digital filters with multilevel magnitude responses is reinterpreted from a different viewpoint. On the basis of this interpretation, techniques for extending these results to the case of finite-impulse-response (FIR) filters are developed. An advantage of the authors' method is that, when the arbitrary-level filter is implemented, its power-complementary filter, which may be required in specific applications, is obtained simultaneously. Also, by means of a tuning factor (a parameter of the scaling matrix), it is possible to generate a whole family of arbitrary-level filters

Programmable Switched Capacitor Finite Impulse Response Filter with Circular Memory Implemented in CMOS 0.18μm Technology

This paper presents a programmable multi-mode finite impulse response (FIR) filter implemented as switched capacitor (SC) technique in CMOS 0.18μm technology. Intended application of the described circuit is in analog base-band filtering in GSM/WCDMA systems. The proposed filter features a regular structure that allows for elimination of some parasitic capacitances, thus significantly improving the filtering accuracy. Due to its modularity that allows for dividing the circuit into two separate sections, the circuit can be easily reconfigured to work as either infinite impulse response (IIR) or as finite impulse (FIR) filter. One of the key components that allows for this multi-mode operation is the proposed programmable and ultra low power multiphase clock circuit. The 24-taps filter for the sampling frequency of 30MHz dissipates power of 4.5mW from a 1.8V suppl

Hybridization of optical plasmonics with terahertz metamaterials to create multi-spectral filters

Multi-spectral imaging systems typically require the cumbersome integration of disparate filtering materials in order to work simultaneously in multiple spectral regions. We show for the first time how a single nano-patterned metal film can be used to filter multi-spectral content from the visible, near infrared and terahertz bands by hybridizing plasmonics and metamaterials. Plasmonic structures are well-suited to the visible band owing to the resonant dielectric properties of metals, whereas metamaterials are preferable at terahertz frequencies where metal conductivity is high. We present the simulated and experimental characteristics of our new hybrid synthetic multi-spectral material filters and demonstrate the independence of the metamaterial and plasmonic responses with respect to each other

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

Analog IC Design at the University of Twente

This article describes some recent research results from the IC Design group of the University of Twente, located in Enschede, The Netherlands.\ud \ud Our research focuses on analog CMOS circuit design with emphasis on high frequency and broadband circuits. With the trend of system integration in mind, we try to develop new circuit techniques that enable the next steps in system integration in nanometer CMOS technology. Our research funding comes from industry, as well as from governmental organizations. We aim to find fundamental solutions for practical problems of integrated circuits realized in industrial Silicon technologies.\ud \ud CMOS IC technology is dictated by optimal cost and performance of digital circuits and is certainly not optimized for nice analog behavior. As analog designers, we do not have the illusion to be able to change the CMOS technology, so we have to "live with it" and solve the problems by design. In this article several examples will be shown, where problematic analog behavior, such as noise and distortion, can be tackled with new circuit design techniques. These circuit techniques are developed in such a way that they do benefit from the modern technology and thus enable further integration. This way we can improve various analog building blocks for wireless, wire-line and optical communication. Below some examples are given.\ud \u

Digital filter design using root moments for sum-of-all-pass structures from complete and partial specifications

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Interleavers

The chapter describes principles, analysis, design, properties, and implementations of optical frequency (or wavelength) interleavers. The emphasis is on finite impulse response devices based on cascaded Mach-Zehnder-type filter elements with carefully designed coupling ratios, the so-called resonant couplers. Another important class that is discussed is the infinite impulse response type, based on e.g. Fabry-Perot, Gires-Tournois, or ring resonators