Yong-Kim Chong

An integrated environment for rapid prototyping of DSP Algorithms using matlab and Texas instruments’ TMS320C30

Abstract This paper presents the implementation of a rapid prototyping system, which involves the design of DSP algorithms using matlab Simulink blocksets, automated code generation, and downloading of executable code to the Texas Instruments’ Evaluation Module (TMS320C30-EVM). Various DSP algorithms were implemented and benchmarked in this system. It demonstrates that the matlab Simulink development system integrated with the TMS320C30-EVM provides a useful development tool for design verification of DSP algorithms. Performance results show that code developed using the rapid prototyping system is highly efficient and the development cycle time is greatly reduced, resulting in lower development cost.

Performance analysis of four memory consistency models for multithreaded multiprocessors

Stochastic timed Petri nets are developed to evaluate the relative performance of distributed shared memory models for scalable multiprocessors, using multithreaded processors as building blocks. Four shared memory models are evaluated: the sequential consistency (SC) model by Lamport (1979), the weak consistency (WC) model by Dubois et al. (1986), the processor consistency (PC) model by Goodman (1989), and the release consistency (RC) model by Gharachorloo et al. (1990). We assumed a scalable network with a sufficient bandwidth to absorb the increased traffic from multithreading, coherent caches, and memory event reordering. The embedded Markov chains are solved to reveal the performance attributes. Under saturated conditions, we find that multithreading contributes more than 50% of the performance improvement, while the improvement from memory consistency models varies between 20% to 40% of the total performance gain. Petri net models are effective to predict the performance of processors with a larger number of contexts than that can be simulated in previous benchmark studies. The accuracy of these memory performance models was validated with the simulation results from Stanford University. Our analytical results reveal the lowest performance of the SC model amongst four memory consistency models. The PC model requires to use larger write buffers, while the WC and RC models require smaller write buffers. The PC model may perform even lower than the SC model, if a small buffer was used. The performance of the WC model depends heavily on the synchronization rate in user code. For a low synchronization rate, the WC model performs as well as the RC model. With sufficient multithreading and network bandwidth, the RC model shows the best performance among the four models. Furthermore, we discovered that cache interferences cause very little performance degradation in all relaxed memory consistency models; as long as the network is contention-free even when multithreading has saturated the system. >

FPGA implementation of parametric loudspeaker system

Abstract Parametric loudspeaker system enables sound to be projected and directed to a specific listening area just like a beam of light. The advancement of Field Programmable Gate Array (FPGA) technology opens up a very interesting option for rapid implementation and easy configurable signal processing platform for parametric loudspeaker system. In this paper, the digital signal processing subsystem of the parametric loudspeaker system has been designed and implemented in FPGA platform using the Altera 1S10 device.

Rapid prototyping of DSP algorithms on VLIW TMS320C6701 DSP

Abstract In this paper, an overview of a rapid prototyping system using MATLAB Real-Time Workshop (RTW) and TI TMS320C6701-EVM is presented. The MATLAB RTW generated ANSI C code from Simulink blocksets has poor real-time implementation benchmarks for DSP kernels. To improve the performance of the DSP kernel blocksets on TI TMS320C6701 DSP, a design methodology employing various levels of optimising techniques are discussed and these algorithms are evaluated on the DSP. Modulo scheduling theory is applied to improve the loop performance. Performance results show that code developed based on optimal scheduling for the C6000 prototyping system is highly efficient. The optimised blockset provides an easy-to-use and highly efficient real-time DSP algorithm development platform.

Elevated speaker projection for digital home entertainment system

This paper presents a novel processing technique to enhance the sound images with playback over elevated loudspeakers for both two-speaker and multiple-speaker configuration. This is achieved by a specially designed inverse filter together with HRTF filtering.

Integrated Headsets Using the Adaptive Hybrid Active Noise Control System

An integrated approach towards the development of an active noise control (ANC) headset for audio and communication applications is explored and evaluated. Two different ANC methods are presented and their performance compared. The first method called the integrated feedback active noise control (IFBANC) system employs adaptive feedback ANC technique. Its main advantage is the use of a single error microphone per ear-cup. The second method is the integrated hybrid active noise control (IHANC) system. This approach combines adaptive feedforward and feedback ANC techniques and requires the use of an error microphone and a reference microphone that is mounted on the external of the ear-cup. Simulations have been conducted for both integrated ANC methods and they performed equally well in the lower frequency range. However, the IHANC system continues to perform moderately well in the mid frequency range where the IFBANC system exhibits only slight attenuation. In addition, the IHANC system performs better than the IFBANC system in attenuating narrowly spaced periodic noise in the lower frequency range

A vehicular noise surveillance system integrated with vehicle type classification

This paper introduces an ongoing project on the surveillance of noisy vehicles on the road. Noise pollution created by vehicles on urban roads is becoming more severe. To enforce current measures, we developed a vehicular noise surveillance system including a vehicle type classification method. Samples of vehicular noise were recorded on-site using this system. Harmonic features were extracted from each sample based on an average harmonic structure. The k-nearest neighbor (KNN) algorithm was applied to achieve classification accuracies for the passenger car, the van, the lorry, the bus, and the motorbike of 60.66%, 65.38%, 52.99%, 62.02%, and 80%, respectively. This study was motivated by the demand of monitoring noise levels generated by different types of vehicles. The classification method using audio features is independent of lighting condition, thus providing a replacement to machine vision based techniques in vehicle type classification.

Selective focusing with numerical technique of time reversal operator decomposition

Recently, a time reversal operator method that is applied to ultrasonic detection and focusing with arrays of transducers has been proposed. This method is known as the DORT (Decomposition de lpsilaOperateur de Retournement Temporel). The DORT method requires the measurement of the inter-element impulse responses of the propagating medium for all pairs of elements in the array. Time reversal operator (TRO) is deduced from these responses and diagonalized. The eigenvector and eigenvalue of TRO is analyzed to perform selective focusing on different scatterers. We develop the numerical technique of DORT method by using the Greenpsilas function estimation in homogeneous and multiple scattering medium. This technique can set up the feasibility study of DORT method to perform selective focusing on multiple scatterers.

A Novel Approach to Bass Enhancement in Automobile Cabin

An audio enhancement system is presented to improve the sound quality, especially the bass reproduction in the automobile cabin. High quality audio reproduction in cabin can be difficult due to a number of factors, including the noise in the cabin, performance, size of the loudspeakers in the car. The proposed system uses digital signal processing techniques with the built-in car audio system to tune and make use of the engine noise. The main problems are the tracking of the engine noise and tune the noise to match the audio signal. In this paper, we propose a solution based on frequency sampling filters to track and extract the audio signal, and a multi-frequency active noise equalizer to tune the engine noise. The results showed that the proposed system could be a promising approach for solving the bass audio reproduction, together with the noise control problems in automobile

Psychoacoustic hybrid active noise control system

In conventional active noise control (ANC) system, the primary noise is attenuated over the frequency band of interest based simply on the error signal, which does not take into account the human perception of noise. Hence, researchers have developed psychoacoustic ANC system to improve its noise reduction performance from psychoacoustic point of view. However, in this psychoacoustic ANC system, there may be a disturbance that is uncorrelated with the primary noise at the error sensor, which can severely degrade the systems noise reduction performance. Hence, in this paper, a psychoacoustic hybrid ANC system is proposed, which can simultaneously control both the correlated primary noise and uncorrelated disturbance from psychoacoustic point of view. Loudness is used as the psychoacoustic criterion for evaluating the systems noise reduction performance. Simulation results show the effectiveness of the proposed psychoacoustic hybrid ANC system.