Filters digital

The demodulation algorithm is very simple the DSP multiplies the received signal by each carrier, and then filters the result using a FIR filter. This kind of digital filter is phase linear, (constant group delay important for the EC combinations). Other filters may be programmed, other demodulation algorithms may be used. 

Furthermore, it was possible to suppress liftoff and offset effects by using efficient digital filter algorithms. These measures provide the tester with a nearly unbiased picture of the wheel that is to be tested and he can thus conduct a reliable evaluation. 

Consequently, the surface generation becomes a question of producing a matrix of random data that obey the defined height distribution and a prescribed ACF This can be carried out efficiently through the procedure of a 2-D digital filter, proposed by Hu and Tonder [47], as summarized as follows. 

Bromba, M. U. A., and Ziegler, H., Efficient Computation of Polynomial Smoothing Digital Filters, Anal. Chem. 51, 1979, 1760-1762. 

Jones, R., High-Pass and Band-Pass Digital Filtering with Peak to Trough Measurement Applied to Quantitative Ultraviolet Spectrometry, Analyst 112, November 1987, 1495-1498. 

Bialkowski, S. E., Real-Time Digital Filters Finite Impulse Response Filters, Anal. Chem. 60, 1988, 355A-361A. 

S. Agaian et ai, Binary Polynomial Transfomns and Nonlinear Digital Filters (1995)... 

S.C. Rutan, Fast on-line digital filtering. Chemom. Intell. Lab. Syst., 6 (1989) 191-201. 

Fig. 7a-e Proton spectra of 1 a Dissolved in CDC13 b in D20 c in D20/H20 d with presaturation of the water signal e with presaturation using a digital filter. Signals marked with are due to an impurity (solvent from recrystallization of 1)... 

We can improve the appearance of the spectrum by applying a so-called digital filter the result is shown in spectrum (e). 

Sharaf MA, Illman DL, Kowalski BR (1986) Chemometrics. Wiley, New York Williams CS (1986) Designing digital filters. Prentice Hall, New York Wolf D (1999) Signaltheorie. Springer, Berlin Heidelberg New York... 

Phillips, S.C. Essex, J.W. Edge, C.M., Digitally filtered molecular dynamics the frequency specific control of molecular dynamics simulations, J. Chem. Phys. 2000,112, 2586-2597... 

This technique is of high accuracy and is meant to be used in precision measurement instrumentation, for it is inherently insensitive to the DC-offset and the AC-noise in the sinusoidal signal which can be substantially reduced by a great variety of electronic devices ranging from various electronic analogue filters, and digital filters to the most effective lock-in amplifiers. 

Example 18.11. Suppose we want to find a discrete approximation for a first-order lag. This would be called a first-order digital filter. Let x, be the output of the filter and m ) be the input. 

Example 18.12. Repeating Example 18.11 for a digital filter, using trapezoidal approximation gives... 

Rearranging gives the transfer function for the digital filter using trapezoidal approximation... 

This is the transfer function for a first-order digital filter. Thus the precompensator slows down the input to the controller so that it does not see a step change in the error signal (see (Fig. 20.3h). 

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