tailieunhanh - DISCRETE-SIGNAL ANALYSIS AND DESIGN- P37

DISCRETE-SIGNAL ANALYSIS AND DESIGN- P37:Electronic circuit analysis and design projects often involve time-domain and frequency-domain characteristics that are difÞcult to work with using the traditional and laborious mathematical pencil-and-paper methods of former eras. This is especially true of certain nonlinear circuits and sys- tems that engineering students and experimenters may not yet be com- fortable with. | 166 GLOSSARY Intermodulation. Two or more input signals combine in a nonlinear circuit or device to create spurious output frequencies. Inverse discrete Fourier transform IDFT . Converts the frequency domain X k to the time domain x n . Defined according to Bracewell. Inverse fast Fourier transform IFFT . A high-speed alternative for the IDFT. A Mathcad function defined according to Bracewell. Laplace transform. Converts a function in the S -plane o j domain to a function in the time domain. The inverse transform performs the opposite process. Mathcad. A personal computer program that performs a very wide range of mathematical calculations either numerical or symbolic in interactive form. Mathcad program. A structured set of logical operations that perform branching counting and loop procedures in a Mathcad worksheet. Mathcad X-Y Trace. A Mathcad utility that displays x and y values on a Mathcad graph. Mathtype. A program from Design that is used to enter equations into a word-processing document. Multiplication. A math process such as 3 x 4 12 or a x b c. Two types of multiplication are sequence and polynomial. Two properties are commutative and associative. Multisim. A program from National Instruments Co. that aids in circuit and system simulation using accurate device models and embedded test instruments and sophisticated graphing capabilities. Non-real-time analysis. The signal is stored in memory and the analysis is performed at the speed of the computer not at the same rate as the signal itself. Normal distribution. The Gaussian probability density function of x from x minus infinity to x plus infinity. The cumulative distribution function CDF is the area under the curve from xmin to xmax. Odd symmetry. The two sides X k and X N k of a phasor spectrum have opposite phase. One-sided sequence. A sequence in which all components are in the positive-frequency or positive-time domain. The sequence is constructed from the two-sided sequence. GLOSSARY .