Analysis of irrational transfer functions for distributed-parameter systems
Algorithmic and digital computer method for approximating irrational transfer functions by rational functions in control systems
Chen, C.-F.↗
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Use of a multichannel scaler and computing calculator to generate optical transfer functions
Multichannel scaler as interface between edge scan unit and calculator to generate optical transfer functions
Klingman, E. E.↗
Applications of Displacement Transfer Functions to Deformed Shape Predictions of the GIII Swept-Wing Structure
The displacement transfer functions (DTFs) were applied to the GIII swept wing for the deformed shape prediction. The calculated deformed shapes are very close to the correlated finite element results as well as the measured data. The convergence study showed that using 17 strain stations, the wing-tip displacement prediction error was 1.6 percent, and that there is no need to use a large number of strain stations for G-III wing shape predictions.
on board string sensing system↗
Determination of transfer function of COPE correlation interferometer instrument
The comparison of theoretical and instrument response functions and its use as a procedure for determining the transfer function of the COPE correlation interferometer are summarized. Data show qualitative agreement can be obtained when discrepancies between theory and instrument are investigated and instrument components are analyzed in detail. Data were obtained using a set of calibration data and computer algorithms.
Twitty, J.↗
A method to define a minimum-phase transfer function within the bounded region of phase-gain specifications
Method to define minimum phase transfer function within bounded region of phase gain specifications at several discrete frequencies
Fontenot, J. W.↗
The transfer function method for gear system dynamics applied to conventional and minimum excitation gearing designs
A transfer function method for predicting the dynamic responses of gear systems with more than one gear mesh is developed and applied to the NASA Lewis four-square gear fatigue test apparatus. Methods for computing bearing-support force spectra and temporal histories of the total force transmitted by a gear mesh, the force transmitted by a single pair of teeth, and the maximum root stress in a single tooth are developed. Dynamic effects arising from other gear meshes in the system are included. A profile modification design method to minimize the vibration excitation arising from a pair of meshing gears is reviewed and extended. Families of tooth loading functions required for such designs are developed and examined for potential excitation of individual tooth vibrations. The profile modification design method is applied to a pair of test gears.
Mark, W. D.↗
Theoretical transfer functions for the Saturn 5 Final report
Laplace transformations and Euler-Lagrange equations for theoretical transfer functions for Saturn 5 launch vehicle
Soifer, M. T.↗
Systems and Methods for Transfer Function Estimation Using Membership Functions
An apparatus, method, and computer program that can learn a linear or non-linear transfer function are disclosed. In one embodiment, for example, a computer-implemented method may include creating a plurality of combinations for at least one input, and calculating an output for the plurality of combinations. The method may also include calculating an error based on the calculated output.
Krasowski, Michael J↗
Best Practices for Measuring the Modulation Transfer Function of Video Endoscopes
Endoscopes are crucial for assisting in surgery and disease diagnosis, including the early detection of cancer. The effective use of endoscopes relies on their optical performance, which can be characterized with a series of metrics such as resolution, vital for revealing anatomical details. The modulation transfer function (MTF) is a key metric for evaluating endoscope resolution. However, the 2020 version of the ISO 8600-5 standard, while introducing an endoscope MTF measurement method, lacks empirical validation and excludes opto-electronic video endoscopes, the largest family of endoscopes. Measuring the MTF of video endoscopes requires tailored standards that address their unique characteristics. This paper aims to expand the scope of ISO 8600-5:2020 to include video endoscopes, by optimizing the MTF test method and addressing parameters affecting measurement accuracy. We studied the effects of intensity and uniformity of image luminance, chart modulation compensation, linearity of image digital values, auto gain control, image enhancement, image compression and the region of interest dimensions on images of slanted-edge test charts, and thus the MTF based on these images. By analyzing these effects, we provided recommendations for setting and controlling these factors to obtain accurate MTF curves. Our goal is to enhance the standard’s relevance and effectiveness for measuring the MTF of a broader range of endoscopic devices, with potential applications in the MTF measurement of other digital imaging devices.
47 OTHER INSTRUMENTATION↗
Experimental evaluation of four transfer functions for a single tube boiler which are dynamically independent of exit restrictions
Experimental evaluation of four transfer functions for single tube boiler and demonstration of functions being independent of exit restrictions
Goodykoontz, J. H.↗
Modulation Transfer Function (MTF) measurement techniques for lenses and linear detector arrays
Application is the determination of the Modulation Transfer Function (MTF) for linear detector arrays. A system set up requires knowledge of the MTF of the imaging lens. Procedure for this measurement is described for standard optical lab equipment. Given this information, various possible approaches to MTF measurement for linear arrays is described. The knife edge method is then described in detail.
Schnabel, J. J., Jr.↗
Transfer function matrix
Given a multivariable system, it is proved that the numerator matrix N(s) of the transfer function evaluated at any system pole either has unity rank or is a null matrix. It is also shown that N(s) evaluated at any transmission zero of the system has rank deficiency. Examples are given for illustration.
Seraji, H.↗
Measuring Dynamic Transfer Functions of Cavitating Pumps
A water-flow test facility has been built to enable measurement of dynamic transfer functions (DTFs) of cavitating pumps and of inducers in such pumps. Originally, the facility was intended for use in an investigation of the effects of cavitation in a rocket-engine low-pressure oxygen turbopump. The facility can also be used to measure DTFs of cavitating pumps in general
Baun, Daniel↗
Transfer-function-parameter estimation from frequency response data: A FORTRAN program
A FORTRAN computer program designed to fit a linear transfer function model to given frequency response magnitude and phase data is presented. A conjugate gradient search is used that minimizes the integral of the absolute value of the error squared between the model and the data. The search is constrained to insure model stability. A scaling of the model parameters by their own magnitude aids search convergence. Efficient computer algorithms result in a small and fast program suitable for a minicomputer. A sample problem with different model structures and parameter estimates is reported.
Seidel, R. C.↗
Ground Test of the Urine Processing Assembly for Accelerations and Transfer Functions
This viewgraph presentation gives an overview of the ground test of the urine processing assembly for accelerations and transfer functions. Details are given on the test setup, test data, data analysis, analytical results, and microgravity assessment. The conclusions of the tests include the following: (1) the single input/multiple output method is useful if the data is acquired by tri-axial accelerometers and inputs can be considered uncorrelated; (2) tying coherence with the matrix yields higher confidence in results; (3) the WRS#2 rack ORUs need to be isolated; (4) and future work includes a plan for characterizing performance of isolation materials.
Houston, Janice↗
Representation of the transfer functions of given structures by their eigen-vibrations, taking into consideration any arbitrary excitation
Eigen-vibration representation of transfer functions for structures by considering arbitrary excitations
Schindelin, J. W.↗
Discrete regulation of transfer function of a circuit in experimental data automatic collection and processing systems
A device for discrete control of the circuit transfer function in automatic analog data processing systems is reported that coordinates the dynamic range of the vibration level change with the signal range of the processing device output. Experimental verification of the device demonstrates that its maximum control speed does not exceed 0.5 sec for a frequency nonuniformity of about 10%.
Lyubashevskiy, G. S.↗
Imaging performance of annular apertures. III - Apodization and modulation transfer functions
Apodization functions with decreasing transmission and their opposite, functions with increasing transmission, are investigated for various central obstruction ratios. The resultant modulation transfer functions are presented for various transmission functions and central obstruction ratios. Conclusions applicable to the improvement of imaging performance are discussed.
Tschunko, H. F. A.↗