Richard C. S. Morling

A novel method to count the red blood cells in thin blood films

This paper describes a novel idea to identify the total number of red blood cells (RBCs) as well as their location in a Giemsa stained thin blood film image. This work is being undertaken as a part of developing an automated malaria parasite detection system by scanning a photograph of thin blood film in order to evaluate the parasitemia of the blood. Not only will this method eliminates the segmentation procedures that are normally used to segment the cells in the microscopic image, but also avoids any image pre-processing to deal with non uniform illumination prior to cell detection. The method utilizes basic knowledge on cell structure and brightness of the components due to Giemsa staining of the sample and detects and locates the RBCs in the image.

An integrated 256-point complex FFT processor for real-time spectrum analysis and measurement

This paper describes in detail the design of a custom CMOS Fast Fourier Transform (FFT) processor for computing 256-point complex FFT. The FFT is well suited for real-time spectrum analysis in instrumentation and measurement applications. The FFT butterfly processor consists of one parallel-parallel multiplier and two adders. It is capable of computing one butterfly computation every 100 ns thus it can compute 256-complex point FFT in 25.6 /spl mu/s excluding data input and output processes.

Living and Dealing with RF Impairments in Communication Transceivers

This paper provides an overview of the sources and effects of the RF impairments limiting and rendering the performance of the future wireless communication transceivers costly as well as hindering their wide-spread use in commercial products. As transmission bandwidths and carrier frequencies increase effect of these impairments worsen. This paper studies and presents analytical evaluations of the performance degradation due to the RF impairments in terms of bit-error-rate and image rejection ratio. The paper also give highlights of the various aspects of the research carried out in mitigating the effects of these impairments primarily in the digital signal processing domain at the baseband as well as providing low-complexity hardware implementations of such algorithms incorporating a number of power and area saving techniques

A high-fidelity decimator chip for the measurement of sigma-delta modulator performance

This paper reports on results from the algorithmic design and simulation of a two-path polyphase decimation filter with 24-bit accuracy over the frequency range from dc to 15.2 kHz. The filter is suited for very high precision data conversion and measurement applications. The device reported in this paper has been designed for use with a fourth-order, single-loop, /spl Sigma//spl Delta/ modulator running at 4096 kHz. Results of floating and fixed-point simulations, architectural design, comparative bit-level simulations and silicon implementation of the decimator are also reported, together with a sample baseband measurement of a fourth-order modulator. >

Adaptive compensation of analog front-end I/Q mismatches in digital receivers

I and Q channel phase and gain mismatches are of great concern in communications receiver design. In this paper we analyse the effects of I and Q channel mismatches and propose a low-complexity blind adaptive algorithm to minimize this problem. The proposed solution consists of two, 2-tap adaptive filters, arranged in Adaptive Noise Canceller (ANC) set-up, with the output of one cross-fed to the input of the other. The system works as a de-correlator eliminating I and Q mismatch errors.

Adaptive self-calibrating image rejection receiver

An adaptive self-calibrating image rejection receiver is described, containing a modified weaver image rejection mixer and a digital image rejection processor (DIRP). The blind source-separation-based DIRP eliminates the I/Q errors improving the image rejection ratio (IRR) without the need for trimming or use of power-hungry discrete components. Hardware complexity is minimal, requiring only two complex-coefficients; hence it can be easily integrated into the signal processing path of any receiver. Simulation results show that the proposed approach achieves 75-97 dB of IRR.

Automated malaria parasite detection in thin blood films:- A hybrid illumination and color constancy insensitive, morphological approach

This paper illustrates the automated diagnosis of malaria parasite (Plasmodium species) in microscopic images of Giemsa stained thin blood films. The procedure adapts a morphological approach for blood cell identification and uses the image features such as intensity, histogram, relative size and geometry for further analysis. Two methods of object classification have been described for parasite detection; one based on relative size and morphology and the other based on intensity variation. Furthermore, an analytical study on both methods has been performed in order to validate the accuracy of the methods.

On the structure, convergence and performance of an adaptive I/Q mismatch corrector

The I/Q mismatches in quadrature radio receivers results in finite and usually insufficient image rejection, degrading the performance greatly. We present a detailed analysis of a blind-source separation (BSS) based mismatch corrector in terms of its structure, convergence and performance. The results indicate that mismatch can be effectively compensated during normal operation and also in rapidly changing environments. Since the compensation is carried out before any modulation specific processing, the proposed method works with all standard modulation formats and is amenable to low-power implementations.

Activity-Monitoring Completion-Detection (AMCD): a new single rail approach to achieve self-timing

A new method for designing single rail asynchronous circuits is studied. It utilises additional circuitry to monitor the activity of nodes within combinational logic blocks. When all transitions have halted a completion signal is generated. Details of the circuit and design methodology are given and the influence of glitches on the proposed circuit is discussed. Three different levels of granularity are investigated. Experimental physical layout of the circuit with extracted and back-annotated simulation results is provided. The proposed approach results in faster operation than synchronous circuits with minimum circuit overhead incurred.

Adaptive digital receivers for analog front-end mismatch correction

Phase and gain mismatches between the I and Q analog signal processing paths of a quadrature receiver are responsible for the generation of image signals which limit the dynamic range of a practical receiver. We analyse the effects of these mismatches and propose a low-complexity blind adaptive algorithm to minimize this problem. The proposed solution is based on two, 2-tap adaptive filters, arranged in an adaptive noise canceller (ANC) set-up. The algorithm lends itself to efficient real-time implementation with minimal increase in modulator complexity.