Category: Filters

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 Filter using Op Amp

Universal Active Filter using Op Amp: 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 specialized ICs […]

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 […]

Band Reject Filter Circuit

Band Reject Filter Circuit: In this Band Reject Filter Circuit, frequencies are attenuated in the stop band and passed outside it, as shown in Fig. 15.20(b). As with band pass filters, band reject filters can also be classified as (i) wide and (ii) narrow band. The narrow band reject filter is also called the notch […]

Band Pass Filter Circuit Diagram

Band Pass Filter Circuit Diagram: A Band Pass Filter Circuit Diagram designed to pass signals only in a certain band of frequencies while rejecting all signals outside this band. There are basically two types of Band Pass Filter Circuit Diagram, Wide band pass Narrow band pass A Band Pass Filter Circuit is defined as a […]

Higher Order Filter Design

Higher Order Filter Design: Higher Order Filter Design – From the preceding discussion on filters we can conclude that in the stop band the gain of the filter changes at the rate of 20 db/decade for first order filters and 40 db/decade for second order filters. This means that as the order of the filter […]