Two-Path All-pass Based Half-Band Infinite Impulse Response Decimation Filters and the Effects of Their Non-Linear Phase Response on ECG Signal Acquisition

This paper is based on the novel use of a very high fidelity decimation filter chain for Electrocardiogram (ECG) signal acquisition and data conversion. The multiplier-free and multi-stage structure of the proposed filters lower the power dissipation while minimizing the circuit area which are crucial design constraints to the wireless noninvasive wearable health monitoring products due to the scarce operational resources in their electronic implementation. The decimation ratio of the presented filter is 128, working in tandem with a 1-bit 3rd order Sigma Delta (ΣΔ) modulator which achieves 0.04 dB passband ripples and -74 dB stopband attenuation. The work reported here investigates the non-linear phase effects of the proposed decimation filters on the ECG signal by carrying out a comparative study after phase correction. It concludes that the enhanced phase linearity is not crucial for ECG acquisition and data conversion applications since the signal distortion of the acquired signal, due to phase non-linearity, is insignificant for both original and phase compensated filters. To the best of the authors’ knowledge, being free of signal distortion is essential as this might lead to misdiagnosis as stated in the state of the art. This article demonstrates that with their minimal power consumption and minimal signal distortion features, the proposed decimation filters can effectively be employed in biosignal data processing units.

The Use of Almost Linear Phase IIR filters In DFT Modulated Filter Banks for Communication Systems

This paper is on the use and performance of M-path polyphase Infinite Impulse Response (IIR) filters for channelisation, conventionally where Finite Impulse Response (FIR) filters are preferred. This paper specifically focuses on the Discrete Fourier Transform (DFT) modulated filter banks, which are known to be an efficient choice for channelisation in communication systems. In this paper, the low-pass prototype filter for the DFT filter bank has been implemented using an M-path polyphase IIR filter and we show that the spikes present at the stopband can be avoided by making use of the guardbands between narrowband channels. It will be shown that the channelisation performance will not be affected when polyphase IIR filters are employed instead of their counterparts derived from FIR prototype filters. Detailed complexity and performance analysis of the proposed use will be given in this article.

Fieldworks from the Museum of the Void: Experiments in the Event of an Archive

This exhibition was a research presentation of works made at Center for Land Use Interpretation [CLUI]base in Wendover, Utah, USA between 2008-2010. The project was commissioned by the Centre For Land Interpretation in USA and funded by The Henry Moore Foundation in the UK. Documentation of research conducted in the field as made available as video and installation. An experimental discourse on the preservation of land art was put with GPS drawings and research information displayed as maps and documents. In examining physical sites in Utah, USA, the project connected to contemporary discourse centred on archives in relation to land art and land use. Using experimental processes conceived in relation to key concepts such as event structures and entropy, conceptual frameworks developed by Robert Smithson (USA) and John Latham (UK), the 'death drive' of the archive was examined in the context of a cultural impulse to preserve iconic works. The work took items from Lathams archive and placed them at the canonical 'Spiral Jetty', Smithson land art work at Rozel Point north of Salt Lake City. This became a focus for the project that also highlighted the role of the Getty Foundation in documenting major public artworks and CLUI in creating an American Land Museum. Work was created in the field at extreme remote locations using GPS technologies and visual tools were developed to articulate the concepts of the artists discussed, to engage the exhibition audience in ideas of transformation and entropy in art. Audiences were encouraged to sign a petition to be used in future preservation of spiral jetty currently facing development challenges.