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Digital signal processing (DSP) refers to anything that can be done to a
}$ w1 V9 ?! [8 F6 Ysignal using code on a computer or DSP chip. To reduce certain; b# m& t) e Q( M* N. j q
sinusoidal frequency components in a signal in amplitude, digital filtering
/ f# ] p; _& w* M' J5 S! [is done. One may want to obtain the integral of a signal. If the signal
$ b% B2 ]* j, ]. _comes from a tachometer, the integral gives the position. If the signal is. J! x+ s+ `: w* n! A
noisy, then filtering the signal to reduce the amplitudes of the noise
+ p8 [& P) F' u" I5 C- \frequencies improves signal quality. For example, noise may occur from1 S% j, g3 Q) r8 y- q
wind or rain at an outdoor music presentation. F iltering out sinusoidal
S' r+ }) ?% s- w1 @# k) Xcomponents of the signal that occur at frequencies that cannot be( ~; G: c4 U* e% ?8 J# d6 `
produced by the music itself results in recording the music with little wind
$ S4 J# F$ `+ S& h( e: _* vand rain noise. Sometimes the signal is corrupted not by noise, but by
) E/ l$ P ^$ Wother signal frequencies that are of no present interest. If the signal is an- a; ?7 ^ `0 M- x
electronic measurement of a brain wave obtained by using probes applied" @; F) a9 f: ~9 m/ x( U2 J
externally to the head, other electronic signals are picked up by the- A6 q2 o {* M. p* v+ O/ {
probes, but the physician may be interested only in signals occurring at a
2 a* D+ R, ^6 eparticular frequency. By using digital filtering, the signals of interest only4 e: t# q6 K0 L- ~) {7 S
can be presented to the physician. |
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