Design Of High-pass Filters Research Articles

On the design of RC-active highpass filters using 2-OA GIC

The design philosophy for RC-active highpass filters has not received as much consideration as lowpass and bandpass structures. The highpass filter (HPF) has a reasonable passband behaviour at high frequencies, at least up to 10 times the corner frequency. This is difficult to achieve due to the deteriorating behaviour of the practical operational amplifier (OA). In high order ladder structures, widely used because of their low sensitivity, improving the HPF behaviour is equivalent to designing a high quality grounded inductor at high frequencies. This evolves a procedure for the appropriate design of 2-OA GIC (generalized impedance converter) simulated inductances, suitably compensated for the nonideal aspects of the OA such as finite bandwidth, signal handling capability, output resistance, etc. Experimental results for 0.1 dB 7th order Cauer-Chebyshev highpass filters with corner frequencies at 10 KHz and 30 KHz are presented to evaluate the procedure. The two filters are studied at different signal levels using two types of OAs with gain-bandwidth products of 3 and 4.5 MHz.

Transversal resonator digital filters: fast and flexible online processors for biological signals.

In a transversal resonator digital filter (t.r.d.f.) all multipliers are small integers. A wide range of filter characteristics may readily be programmed on currently available 16-bit mini- and microcomputers using elementary machine-code instructions. Online sampling rates up to a few kilohertz are possible. After discussion of the theoretical background, this paper includes a Fortran IV program to aid the design of low-pass, high-pass, and bandpass filters with raised-cosine rolloff characteristics and pure linear phase responses. The practical applications of the t.r.d.f. method are illustrated by designing a set of bandpass filters for e.e.g. analysis and matched filters for the detection of e.c.g. waveforms in noise.

高域通過形分布定数流体フィルタの設計

高域通過形分布定数流体フィルタの設計

Eigenschaften diskreter Ortsfilter

Properties of discrete spatial filters are investigated. By introducing rectangular or oblique coordinates it is possible to design filters in a quadratic or hexagonal raster. The design of low-pass, high-pass and band-pass filters is shown. Their properties are evaluated by computing an example; different filters are compared. It is possible to design arbitrary filters; however, there are limitations due to quantization error and approximation of filters by a necessarily finite (and small) number of elements.

The Design of Active Distributed Filters

We develop a synthesis method which leads to simple realizations of low-pass and high-pass active filters using distributed resistance-capacitance networks. In the low-pass filter there is one distributed network terminated, through a negative impedance converter, in a load consisting of a lumped network or another distributed network. Thus we can obtain a Chebyshev-like low-pass filter which has a faster cutoff than a four pole Chebyshev realization with the same ripple. In the high-pass filter design an additional feedback element is involved. We can obtain a complex pole pair to be placed anywhere in the complex frequency plane except the real frequency axis. Design charts are given.