This paper deals with the continuous development of digital signal processing in the field of test and measurement. Continuous process of development of filters to meet he challenges of bandwidth and accuracy. The real time oscilloscope has been the mainstay of electronic and R&D applications. DSP is a well established discipline. It has become the enabling toll to extend the oscilloscope bandwidth beyond the current analogue limits and to improve the overall measurement accuracy. This above said extension in bandwidth of oscilloscope is made to reality with the help of filtering technique. In addition, the various developments in digital filters in the field of digital signal processing is discussed.
Digital signal processing is a processing of signals on a digital computer, the operations performed on a signal consists of a number of mathematical operations as specified by a software program. In a broader sense the digital system can be implemented as a combination of digital hard ware and software, each of which performs its own set of specified operations.This rapid development is a result of the significant advances in digital computer technology & integrated circuit fabrication. The rapid developments in integrated circuit technology such as VLSI of electronic circuits has spurred the development of powerful smaller & cheaper digital computers & special purpose digital hardware. These inexpensive & relatively fast digital circuits have made it possible to construct highly sophisticated digital systems capable of performing complex DSP functions & tasks, which are usually too difficult and/or too expensive to be performed by analog signal processing systems.
As most of the signals are analog, so these are to be converted into digital signals for carrying out processing in digital form. Processing of a input signal is nothing but performing specified operations on it according to the requirement . After processing , signals can be reconverted to analog form if desired. Filter is the most vital system in the DSP technology. Digital filters are classified by their use & implementation. These are called time domain or frequency domain based on their use, and finite impulse response(FIR) and infinite impulse response(IIR). Now a days WAVELET TRANSFORM have played tremendous role in DSP technology.
Most of the signals encountered in science & engineering are analog in nature. That is, the signals are functions of a continuous variable, such as time or space, and usually take on values in a continuous range. Such signals may be processed directly by appropriate analog systems(such as filters or frequency analyzers) or frequency multipliers for the purpose of changing their characteristics or extracting some desired information. In such a case we say that the signal has been processed directly in its analog form. Here both the input signal & the o/p signal are in analog form.