scholarly journals Digital spotlighting filtering optimization for SAR imaging

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Eric J. Balster ◽  
David B. Mundy ◽  
Andrew M. Kordik ◽  
Kerry L. Hill
Keyword(s):  
Image Quality ◽  
Finite Impulse Response ◽  
Computational Cost ◽  
Synthetic Aperture ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Wide Range ◽  
Low Pass ◽  
Filter Type ◽  
Low Pass Filters

AbstractIn this paper, a synthetic aperture radar (SAR) image formation simulator is used to objectively evaluate the parameter selection within the digital spotlighting process. Specifically, recommendations for the filter type and filter order of the low-pass filters used in the range and azimuth decimation processes within the digital spotlighting algorithm are determined to maximize image quality and minimize computational cost. Results show that a finite impulse response low-pass filter with a Taylor $(\overline {n}=5)$(n¯=5) window applied provides the highest image quality over a wide range of filter orders and decimation factors. Additionally, a linear relationship between filter length and decimation factor is found.

scholarly journals Computing efficiency of the three-stage interpolated low pass filters

2018 ◽  
Vol 28 (4) ◽  
pp. 21-27
Author(s):  
I. S. Savinykh ◽  
D. A. Chemasov
Keyword(s):  
Impulse Response ◽  
Computational Efficiency ◽  
Finite Impulse Response ◽  
Sampling Rate ◽  
Efficiency Coefficient ◽  
Transition Band ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Low Pass Filters

Undoubted advantages of finite impulse response filters are their unconditional stability, the absence of limit cycles and the possibility of implementing a filter that does not introduce phase distortion. The disadvantage of such filters is the large cost required to compute the response. This paper considers three-stage interpolated finite impulse response low-pass filters. The maximum values of the interpolation factors are determined. Dependences of the coefficient of computational efficiency and the coefficient of increase in the registers of the three-stage interpolated low-pass filter on the values of the interpolation factors, the widths of the passband and the transition band are obtained. Relations for determining the optimal values of interpolation factors corresponding to the maximal value of computational efficiency coefficient are obtained. In addition, the dependencies of the maximum coefficient of computational efficiency and the optimal coefficient of increase in the registers of the three-stage interpolated low-pass filter on the widths of the passband and the transition band at the optimum values of the interpolation factors are obtained. Considered three-stage interpolated low-pass filters should be used in the case when the required stopband is significantly less than the sampling rate. In this case, three- stage interpolated filters require less computational resources for calculating the response than the two-stage interpolated filters or filter implemented by the transversal structure.

scholarly journals Designing Microstrip Low Pass Filter In ISM Band For Rectenna System

2012 ◽  
Vol 1 (4) ◽  
pp. 356
Author(s):  
Pavan Sharma ◽  
Veerendra Jadaun ◽  
Devesh Mahor ◽  
Atal Verma
Keyword(s):  
Power Transmission ◽  
Wireless Power ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Communication Techniques ◽  
Filter Structure ◽  
Rf Communication ◽  
Power Transmission Systems ◽  
Low Pass ◽  
Low Pass Filters

The filter is required in all RF-communication techniques. Low Pass Filters play an important role in wireless power transmission systems. Transmitted and received signals have to be filtered at a certain frequency with a specific bandwidth. In this paper the design of filter is done in the ISM (Industrial, Scientific and Medical) band whose frequency lies between 1.55GHz- 3.99GHz. After getting the specifications required, we realized the filter structure with the help of CST-MW software.

Characterization of Low-pass Filters on Local Fields of Positive Characteristic

2016 ◽  
Vol 59 (3) ◽  
pp. 528-541 ◽  
Author(s):  
Qaiser Jahan
Keyword(s):  
Positive Characteristic ◽  
Sufficient Conditions ◽  
Local Fields ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Necessary And Sufficient ◽  
Low Pass Filters ◽  
The Scaling Function

AbstractIn this article, we give necessary and sufficient conditions on a function to be a low-pass filter on a local field K of positive characteristic associated with the scaling function for multiresolution analysis of L2(K). We use probability and martingale methods to provide such a characterization.

METHOD FOR MEASURING THE EQUIVALENT PARAMETERS OF INDUCTORS AS PART OF LOW-PASS FILTERS

2020 ◽  
pp. 19-29
Author(s):  
A. G. Zinovev ◽  
I. A. Shestakov
Keyword(s):  
The Self ◽  
Network Analyzer ◽  
Q Factor ◽  
Practical Application ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Loss Resistance ◽  
Low Pass ◽  
Low Pass Filters ◽  
Fifth Order

A method for measuring the self-capacitance, inductance, loss resistance, and Q-factor of inductors as part of an LC low-pass filter at its operating frequency is presented. An example of the practical application of this method for measuring the equivalent pa-rameters of inductors and capacitors as part of a fifth-order Cauer low-pass filter using network analyzer.

A New Capacitance Multiplier Structure with High Multiplication Factor for Ultra-Low-Frequency Filter in Biomedical Applications

2019 ◽  
Vol 29 (07) ◽  
pp. 2050109
Author(s):  
Yan Li ◽  
Yong Liang Li
Keyword(s):  
Biomedical Applications ◽  
Low Frequency ◽  
Multiplication Factor ◽  
Frequency Filter ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Physiological Signal ◽  
Wide Range ◽  
Low Pass ◽  
Capacitance Multiplier

A novel capacitance multiplier is proposed to implement an ultra-low-frequency filter for physiological signal processing in biomedical applications. With the proposed multiplier, a simple first-order low-pass filter achieves a [Formula: see text]3-dB frequency of 33.4[Formula: see text]μHz with a 1-pF capacitance and a 20[Formula: see text]k[Formula: see text] resistance. This corresponds to a multiplication factor of as large as [Formula: see text]. By changing the controlling terminal, the [Formula: see text]3-dB frequency can be tuned in a wide range of 33.4[Formula: see text]μHz–6.3[Formula: see text]kHz.

A Low-Pass Filter Type of Delta Modulation

1978 ◽  
Vol AES-14 (2) ◽  
pp. 393-400
Author(s):  
Toshihiko Yamawaki ◽  
Taikyu Kim
Keyword(s):  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Filter Type ◽  
Delta Modulation

Turbulence Estimation Using Fast-Response Thermistors Attached to a Free-Fall Vertical Microstructure Profiler

2016 ◽  
Vol 33 (10) ◽  
pp. 2065-2078 ◽  
Author(s):  
Yasutaka Goto ◽  
Ichiro Yasuda ◽  
Maki Nagasawa
Keyword(s):  
Temperature Gradient ◽  
Frequency Response ◽  
Turbulence Intensity ◽  
Free Fall ◽  
Fast Response ◽  
Double Pole ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Wide Range ◽  
Low Pass

AbstractEstimation of turbulence intensity with a fast-response thermistor is examined by comparing the energy dissipation rate from a Fastip Probe, model 07 (FP07), thermistor with from a shear probe, both of which are attached to a free-fall microstructure profiler with the fall rate of 0.6–0.7 m s−1. Temperature gradient spectra corrected with previously introduced frequency response functions represented by a single-pole low-pass filter yields with a bias that strongly depends on turbulence intensity. Meanwhile, the correction with the form of a double-pole low-pass filter derives less bias than of single-pole low-pass filter. The rate is compatible with when the double-pole correction with the time constant of 3 × 10−3 s is applied, and 68% of data are within a factor of 2.8 of in the wide range of = 10−10–3 × 10−7 W kg−1. The rate is still compatible with even in the anisotropy range, where the buoyancy Reynolds number is 20–100. Turbulence estimation from the fast-response thermistor is thus confirmed to be valid in this range by applying the appropriate correction to temperature gradient spectra. Measurements with fast-response thermistors, which have not been common because of their poor frequency response, are less sensitive to the vibration of profilers than those with shear probes. Hence, measurements could be available when a fast-response thermistor is attached to a CTD frame or a float, which extends the possibility of obtaining much more turbulence data in deep and wide oceans.

scholarly journals Modelling of Butter worth low pass Stepped Impedance Microstrip line Filter

2020 ◽  
Vol 8 (5) ◽  
pp. 1225-1229
Keyword(s):  
Communication Systems ◽  
Return Loss ◽  
Satellite Communication ◽  
Microwave Filter ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Microwave Application ◽  
Low Pass ◽  
Radar Satellite ◽  
Low Pass Filters

This paper presents the design of a class of highly selective micro strip low pass filters. The proposed structure is considered for Stepped Impedance Low Pass Butterworth filter of order n=3 and n=5 with cut-off frequency 1.2 GHz and passband ripple of 3.01db [1]. The substrate FR4 having a dielectric constant 4.4 is considered for calculating the physical length of the micro strip low pass filter. The designing equation are solved using MATLAB Software and the results are analysed and compared using IE3D Simulator. The microwave filter is a building block that provides frequency selectivity in various microwave application like mobile, radar, satellite communication systems. The simulated results show the insertion loss and return loss of about -6.65 dB & - 55.49dB for N=3 and -7.23dB &-16.01 dB for N=5.Simulation has also been done for VSWR.

Low Pass Filter PUF: Authentication of Printed Circuit Boards Based on Resistor and Capacitor Variations

2018 ◽  
Vol 27 (03n04) ◽  
pp. 1840021 ◽  
Author(s):  
Shahed Enamul Quadir ◽  
John A. Chandy
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Process Variations ◽  
Circuit Board ◽  
Circuit Boards ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Printed Circuit ◽  
Low Pass ◽  
Low Pass Filters

Physical Unclonable Functions (PUFs) are probabilistic circuit primitives that extract randomness from the physical characteristics of a device. PUFs are easy and simple to implement and its random nature makes its behavior hard to predict and model. Most existing PUF designs are based on variation at the chip level and can not be implemented in a printed circuit board (PCB). Therefore, these PUFs can not be used to protect against counterfeit PCBs in a distributed supply chain. In this work, we propose a novel PUF design based on resistor and capacitor variations for low pass filters (LoPUF). We demonstrate the setup in a protoboard for different resistor-capacitor pairs (RC pairs) for reliable low pass filter PUF. Because of process variations, the voltage will be different at the same cut-off frequency for our proposed PUF. Finally, the output of the filter is connected to an inverter to measure the pulse width and best suitable pulses are used for ID generation based on our algorithm.

Near‐real time reduction of shipboard gravity using Kalman‐filtered GPS measurements

Geophysics ◽  
1991 ◽  
Vol 56 (12) ◽  
pp. 1971-1979 ◽  
Author(s):  
J. F. Genrich ◽  
J.-B. Minster
Keyword(s):  
Real Time ◽  
Impulse Response ◽  
Finite Impulse Response ◽  
Yield Data ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Marine Gravity ◽  
Gravity Measurements ◽  
Low Pass ◽  
Stabilized Platform

We have developed a Kalman filter to estimate accurate Eötvös corrections and horizontal ship accelerations from Global Positioning System (GPS) fixes. High‐resolution shipboard gravity measurements are obtained with a newly designed, linear phase, Finite Impulse Response (FIR) low‐pass filter. Both filters are combined to yield accurate, near‐real time, Eötvös‐corrected underway gravity estimates. Error ranges that reflect uncertainty in navigation for these estimates are calculated from autocovariances of Kalman velocity estimates by means of variance propagation expressions for time‐invariant linear digital filters. Estimates of horizontal ship acceleration are combined with a simplified instrument impulse response model in an attempt to remove transient noise from the gravimeter output. We apply the technique to data collected by two shipboard gravimeters, a LaCoste & Romberg Model S Air‐Sea Gravity Meter and a Bell Aerospace BGM-3 Marine Gravity Meter System, operated side‐by‐side on the Scripps R/V Thomas Washington during Leg 1 of the Roundabout expedition. In the absence of significant horizontal accelerations due to course or speed changes, both instruments yield data with good repeatability, characterized by rms differences of less than 1 mGal. Horizontal accelerations generate transient signals that cannot be modeled at present to an accuracy of better than 5 mGal. Difficulties in removing these transients are primarily due to insufficient quantitative knowledge of the response of the instrument, including the gyro‐stabilized platform. This can be determined analytically or empirically.

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