ITB Journal of Information and Communication Technology (Nov 2008)
Welch Based Denoising Technique for a Set of Chirp Signals Corrupted by Gaussian Noises
Abstract
The aim of this paper is to investigate the performance of Welch based de-noising technique for a set of chirp signals corrupted by Gaussian noises. In telecommunications, chirp signals are widely studied, particularly for sonar, radar and spread spectrum applications. However, unlike conventional signals, chirp signals are typical of time varying frequency signals. It sweeps linearly from a low to a high frequency. It is in fact a signal in which its frequency increases or decreases with time. Results indicate that by using Welch based de-noising technique; the noise can be inhibited effectively. However, this method works satisfactory only below its threshold point. Beyond this limit, the de-noising process we perform results in the unsatisfactory results, due to unacceptable value of signal-to-noise ratio obtained. This case is similar to the case of radar. Radar can only detect the presence of the aircraft at a certain limited distance only. If the aircraft moves further apart, then the transmitted signals become weaker and weaker before the noise can completely overwhelm it. It turns out that the presence of the aircraft cannot be recognised further.