Constant K Filter | Prototype Filter

pi configuration of band stop constant k filter

In this filter, the series and shunt impedances ( and  ) are such that, (constant) where  is a real number and independent of frequency. It is conventionally known as the design impedance of the section. Any filter, where this relationship is maintained is known as constant K or prototype filter. It can also be classified utilizing low pass, high pass, bandpass, and bandstop configuration. Constant K Low Pass Filter (LPF) It is the simplest type of filter which allows all frequencies, up to the specified cut-off frequency, to pass through…

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m Derived Filter

corresponding of constant k pi section filter

m Derived filter is introduced in order to overcome the drawback of constant-k filters. So at first let’s see the drawback. Constant-k filters have two main drawbacks In the attenuation band, the attenuation does not increase sharply with frequency beyond the cutoff frequency. In the pass band, Z0 does not remain constant but varies widely from the nominal value R0. Hence when constant-k filter is terminated in a fixed resistive load, mismatch and associated reflection occur at different frequencies. Regarding attenuation characteristic, some improvement in attenuation band beyond cutoff may…

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Parallel Resonance or Anti Resonance Circuit

Parallel Resonance or Anti-Resonance Circuit

A Parallel Resonance or Anti Resonance Circuit consists of an inductor L in parallel with a capacitor C as shown in figure 1. R is a small resistance associated with the inductor L. The capacitor is assumed to be lossless. Let the tuned circuit be driven by a voltage source V. Such a parallel tuned circuit is commonly used in tuned amplifiers, oscillators, filters etc. Analysis of this parallel tuned circuit may be done more conveniently in terms of admittances instead of impedances. Thus, the admittance of the inductive branch…

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Selectivity of Series RLC circuit

Selectivity of Series RLC circuit with Frequency Variable

Impedance of series RLC circuit at operating frequency is given by,            …..(1) If is close to resonant frequency , Equation 1 does not give very accurate results. In such a case, it is desirable to use a more appropriate relation valid only for frequency close to the operating frequency. Thus, equation (1) may be put as,          …..(2) At resonance Hence,         …..(3) Where Q0 is the quality factor of L (or C) at resonance. Hence, equation (2) may be put as,        …..(4) Fractional frequency variation . It…

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Series RLC Resonant Circuits

series RLC resonant circuit

A general two terminal network consists of resistive and reactive components and hence offers a complex impedance. If a sinusoidal voltage is applied to this network, the resulting current is, in general, out of phase with the applied voltage. Under special circumstances, however, the impedance offered by the network is purely resistive and the circuit is said to be in resonance. The frequency of the applied signal at which resonance occurs is called the frequency of response. Under resonance, the circuit has unity (one) power factor. This condition of resonance…

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Band-Stop or Band Elimination Resonant Filter

band stop filter cirucit

This filter eliminate or disallows a band of frequencies extending from say frequency f1 to frequency f2. A band stop filter may simply be obtained by connecting in tandem a low pass filter with a high pass filter and keeping the cutoff frequency f2 of high pass filter higher than the cutoff frequency f1 of low pass filter. The overlapping attenuation bands of the two filters then constitutes the stop band of the band stop filter. Series Resonant Band-stop Filter Series resonant band-stop filter, as illustrated in Fig.1., essentially consists…

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R-C Band Pass Filter | Series and Parallel Resonant

R-C Band-Pass Filter Sometime it is desirable to pass a certain band of frequencies and to attenuate other frequencies on both sides of this passband. The pass-band is called the bandwidth of the filter. It can be achived by cascading low-pass filter capable of transmitting all frequencies upto to a high pass filter capable of transmitting all frequencies higher than , with . The system devloped will be capable of transmitting frequencies between and and attenuate all other frequencies below and above . The passband of this filters is given…

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High Pass Filter Circuit | R-C, R-L Inverted L, T and Pi Type

RC low pass filter

HIgh-Pass Filters High pass filter are aiso of R-C,R-L, inverted L,T-and types as illustrated in Figs. 1, 2, 3, 4, 5, and 6 respectively. 1. High-Pass R-C Filter Circuit High-pass R-C filter circuit is shown in Fig.1. In this, circuit output voltage is taken across the resistor. This reactance of the capacitor C is given as or i.e Reactance of the circuit capacitor decreases with the increase in frequency, Thus at low frequencies the capacitor C offers considerable reactance and so blocks them, but at higher frequencies it offers little…

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Passive Filter | Low Pass Filter

RC low pass filter

Passive Filters | Low Pass Filter The simplest approach to building a filter is with passive components (resistors, capacitors, and inductors). In the R-F range, it works quite well but with the lower frequencies, inductors create problems. AF inductors are physically larger and heavier, and therefore expensive. For lower frequencies, the inductance is to be increased which needs more turns of wire. It adds to the series resistance which degrades the inductor’s performance. Input and output impedances of passive filters are both a problem, especially below RF. The input impedance…

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Electric Filter | Types of Filter

frequency response of ideal low pass filter

What is Electric Filter? An electric filter is usually a frequency-selective network that passes a specified band of frequencies and blocks or attenuates signals of frequencies outside this band. Or, An Electric filter or simply a filter is an electric network that passes or allows without loss, the transmission of electric signal within a certain frequency range but stops or disallows transmission of electric signal outside this frequency range. Depending on the types of elements used in their construction, filters may be passive or active. A passive filter is built…

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