CT Scan Basic Principle: CT Scan Basic Principle – Biomedicine is one area in which the use of digital signal processing techniques had had great impact. Computer tomography A recent advance in diagnostic analysis is represented by computer tomography (CT) scanning. While in standard radiography (X-rays) a 3-dimensional object (part of the body) is represented […]

### Category: FILTERS

## Modern Radar Systems Analysis

Modern Radar Systems Analysis: Modern Radar Systems Analysis are of great importance for both military and civil applications. The main problem of a typical radar system is the detection of return pulses; this substantially corresponds to determining the presence or absence of a pulse in noise. For such radar systems, the band width is usually […]

## Bandpass Analysis

Bandpass Analysis: There exist many practical situations in which multiple filtering and band pass analysis are required. In multiple filtering, one specific operation (for example low pass, high pass, band pass, etc.) is required to be performed on many signal channels presented as input data, e.g. in multiplex systems. In band pass analysis, many Bandpass […]

## Typical Digital Filtering Operations

Typical Digital Filtering Operations: Digital filters in fact can be applied in many different parts of a signal and image processing transmission system. Two typical examples of systems in which Typical Digital Filtering Operations can be inserted are Local digital processing systems (Fig. 15.42), and Digital communication system (Fig. 15.43) In the first system of […]

## Microprocessor Based Digital filter

Microprocessor Based Digital filter: Microprocessor Based Digital filter – The implementation of any digital filtering consists of a series of multiplications of samples of the input and/or output signals by constants, and of the additions of these products. Thus the main building blocks which have to be present in digital filtering hardware are the following: […]

## IIR Filter Design

IIR Filter Design 1-D: In this section some practical considerations relating to the methods for the design of IIR Filter Design filters are presented. In particular, the bilinear transform is considered along with its application to the digitization of rational transfer functions of classical analog filters defined on the s-plane or in the framework of […]

## IIR Digital Filter Design Methods

IIR Digital Filter Design Methods: IIR Digital Filter Design Methods – Fettveis first suggested the use of one port reflection coefficients for the tranfer of analog filter properties from the analog domain to the digital filter domain, and thus produced the wave digital filter structure. Transformation of Passive Ladder Filter The reason why reflection coefficients […]

## Digital Filter Design Window Method

Digital Filter Design Window Method: We describe the Fourier series technique as the first design method of 1-D FIR digital filters [Eq. (15.83)]. In this Digital Filter Design Window Method, given a frequency function H(ejω) with period 2π, an FIR Digital Filter Design Window Method with a transfer function corresponding to H(ejω) can be obtained by simply […]

## Fast Fourier Transform Formula

Fast Fourier Transform Formula: The Fast Fourier Transform Formula is a computational tool which facilitates signal analysis, such as power spectrum analysis and filter simulation using digital computers. In digital analysis of signals, the continuous waveform to be analysed is first sampled and then converted to digits that represent the amplitude of the samples. The […]

## Frequency Domain Representation

Frequency Domain Representation: Frequency Domain Representation – A very important representation of discrete time systems can be obtained in terms of sinusoidal or complex-exponential signals. This is possible because the linear shift invariant systems have the interesting property that the response to a sinusoidal or complex exponential input is also sinusoidal or complex-exponential, having the […]

## Digital systems fundamentals

Digital systems fundamentals Properties of 1-D: A Digital systems fundamentals can be defined as an operator which transforms an input sequence { x(n)} to an output sequence {y(n)}A system of this type is said to be linear, indicated by the symbol L, if and only if the principle of superposition holds. This is equivalent to […]

## Sampling Theorem

Sampling Theorem 1-D: One of the most important applications of digital filtering is the processing of sequences of samples derived from continuous or analog signals. This is made possible due to the results and implications of the sampling theorem. This theorem can be stated as follows: “A continuous analogue function x(t) which has a limited […]

## Discrete Functions Equation

Discrete Functions Equation: The properties of linear digital filters defined as transformations of discrete functions are described in the following. Discrete Functions Equation are defined only for discrete values of their variables, that is, they are sequences of numbers. These numbers can be obtained as quantised samples of continuous functions (representing an analog signal or image) […]

## Digital Filter Design

Digital Filter Design: It has been seen that control of the band width of a circuit or signal is of paramount importance in optimising the measurement of a signal. Formerly band width control was implemented using frequency, selective active or passive networks of resistors, capacitors and inductors. However, the results obtained were somewhat less than […]

## Active Filters Types

Active Filters Types: There are basically four useful Active Filters Types. Namely Butterworth Chebyschev Bessel Elliptic Butterworth Filter The Butterworth filter has an essentially flat amplitude versus frequency response up to the cutoff frequency. The sharpness of the cutoff can be seen in Fig. 15.27, where it is compared with the Chebyschev and the Bessel […]

## Universal Active Filters

Universal Active Filters: Universal Active Filters – With the advance of integrated circuit technology, integrated circuits with improved capabilities are appearing in ever increasing numbers. Innovative design methods and fabrication procedures have not only helped to produce a large variety of new integrated circuits but also improved the old ones. Often the use of specialised […]

## All Pass Filter Design

All Pass Filter Design: The All Pass Filter Design is one that passes all frequency components of the input signal without attenuation. Any ordinary wire can be used to perform this characteristic but the most important factor in an all pass filter is that it provides predictable phase shifts for different frequencies of the input […]