order filter
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Author(s):  
Oleksii Yanenko ◽  
Leonid Virchenko

Problems. It is noted that the measurement of low-intensity microwave signals of various physical bodies and biological objects is associated with the need to provide high sensitivity, which can reach 10-14 -10-15 watts. The authors of the article studied the selective (selective) filter-amplifier of the switching frequency of the high-sensitivity modulation radiometer as one of the elements that have a significant impact on the sensitivity and accuracy of measurement, and developed recommendations for improving the stability of its parameters. The purpose of the research. The peculiarities of the modulation radiometer conversion channel operation are considered and the role of the selective switching frequency amplifier in providing such sensitivity is determined. The input and output signals of the selective amplifier, their relationship and the effect on the sensitivity of the radiometer were obtained and analyzed. The necessity of application of compensation of influence of temperature on characteristics of the filter taking into account temperature coefficients of elements of the scheme is proved. Conclusions. Modeling of a selective amplifier with a third-order filter was performed, the amplitude-frequency characteristic and the zone of its possible displacement at the maximum operating temperature were obtained. The structural and schematic diagram of the selective amplifier with automatic consideration of temperature influences, due to the introduction of feedback and correction of the frequency response of the filter has been developed. The main parameters of the bandpass filter built on the feedback circuit are determined. The use of a field-effect transistor channel connected in series with the resistors of the frequency-forming circuits of the third-order filter is proposed as an element of frequency response correction. The technical requirements for modeling and development of a selective amplifier are determined, which provide opportunities for implementation in practice. The research can be used to build a highly sensitive radiometric system for measuring low-intensity signals in areas such as biology and medicine.


2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Hemant Amhia ◽  
A. K. Wadhwani

Electrocardiogram (ECG) is commonly used biological signals that show an important role in cardiac analysis. The interpretation and acquisition of QRS complex are significant measures of ECG data dispensation. The R wave has a vital character in the analysis of cardiac rhythm irregularities as well as in the determination of heart rate variability (HRV). This manuscript is proposed to design a new artificial-intelligence-based approach of QRS peak detection and classification of the ECG data. The design of reduced order IIR filter is proposed for the low pass smoothening of the ECG signal data. The min-max optimization is used for optimizing the filter coefficient to design the reduced order filter. In this research paper, elimination of baseline wondering and the power line interferences from the ECG signal is of main attention. The result presented that the accuracy is increased by around 13% over the basic Pan–Tompkins method and around 8% over the existing FIR-filter-based classification rules.


Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7376
Author(s):  
Winai Jaikla ◽  
Unchittha Buakhong ◽  
Surapong Siripongdee ◽  
Fabian Khateb ◽  
Roman Sotner ◽  
...  

This paper presents the design of a voltage-mode three-input single-output multifunction first-order filter employing commercially available LT1228 IC for easy verification of the proposed circuit by laboratory measurements. The proposed filter is very simple, consisting of a single LT1228 as an active device with two resistors and one capacitor. The output voltage node is low impedance, resulting in an easy cascade-ability with other voltage-mode configurations. The proposed filter provides four filter responses: low-pass filter (LP), high-pass filter (HP), inverting all-pass filter (AP−), and non-inverting all-pass filter (AP+) in the same circuit configuration. The selection of output filter responses can be conducted without additional inverting or double gains, which is easy to be controlled by the digital method. The control of pole frequency and phase response can be conducted electronically through the bias current (IB). The matching condition during tuning the phase response with constant voltage gain is not required. Moreover, the pass-band voltage gain of the LP and HP functions can be controlled by adjusting the value of resistors without affecting the pole frequency and phase response. Additionally, the phase responses of the AP filters can be selected as both lagging or leading phase responses. The parasitic effects on the filtering performances were also analyzed and studied. The performances of the proposed filter were simulated and experimented with a ±5 V voltage supply. For the AP+ experimental result, the leading phase response for 1 kHz to 1 MHz frequency changed from 180 to 0 degrees. For the AP− experimental result, the lagging phase response for 1 kHz to 1 MHz frequency changed from 0 to −180 degrees. The design of the quadrature oscillator based on the proposed first-order filter is also included as an application example.


2021 ◽  
Author(s):  
Buddhadeva Sahoo ◽  
Sangram Keshari Routray ◽  
Pravat Kumar Rout ◽  
Mohammed M Alhaider

2021 ◽  
pp. 215-241
Author(s):  
Xiaojie Su ◽  
Yao Wen ◽  
Yue Yang ◽  
Peng Shi

2021 ◽  
Author(s):  
Tinus Stander

Vertical stacking of planar line resonators in multilayer media is an effective footprint reduction technique for high order filters, but strong broadside line coupling often negates the possibility of narrowband filters. It is shown that vertically stacking combline resonators with rotated centerlines leads to moderate bandwidth filters. Four variations of a 5th order filter are demonstrated, achieving 1.92 – 3.3 dB IL over 10% FBW around 10 GHz while occupying between 6.62 – 22.47 mm2 surface area on a 7 layer PCB.


2021 ◽  
Author(s):  
Tinus Stander

Vertical stacking of planar line resonators in multilayer media is an effective footprint reduction technique for high order filters, but strong broadside line coupling often negates the possibility of narrowband filters. It is shown that vertically stacking combline resonators with rotated centerlines leads to moderate bandwidth filters. Four variations of a 5th order filter are demonstrated, achieving 1.92 – 3.3 dB IL over 10% FBW around 10 GHz while occupying between 6.62 – 22.47 mm2 surface area on a 7 layer PCB.


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