Sww(w)=n. (a) white noise (b)Pink noise FIGURE 73.4 Power transform pairs for white and pink noise Figure 73.5 not available FIGURE 73.5 Thermal noise in a resistor. 1990, P. 241. Figure 73. 4(b) shows the sinc function Rpp(s)=F[Spp(w)] for pink noise. Random variables P. and P2 at times t, and t2 are correlated only for t, and t2 close Thermal noise as Gaussian white noise Brown observed in 1828 that pollen and dust particles moved randomly when suspended in liquid. instein analyzed such motion based on the random walk model. Perrin confirmed in 1908 that the ctivity of molecules in a liquid caused irregular bombardment of the much larger particles. It was that charges bound to thermally vibrating molecules would generate electromotive force (emf)at the open rminals of a conductor, and that this placed a limit on the sensitivity of galvanometers. Thermal noise(also called Johnson noise)was first observed by J B. Johnson at Bell Laboratories in 1927. Figure 73.5 displays white noise as seen in the laboratory on an oscilloscop e 2000 by CRC Press LLC© 2000 by CRC Press LLC 1990, p. 241]. Figure 73.4(b) shows the sinc function RPP(s) = F–1[SPP(w)] for pink noise. Random variables P1 and P2 at times t1 and t2 are correlated only for t1 and t2 close. Thermal Noise as Gaussian White Noise Brown observed in 1828 that pollen and dust particles moved randomly when suspended in liquid. In 1906, Einstein analyzed such motion based on the random walk model. Perrin confirmed in 1908 that the thermal activity of molecules in a liquid caused irregular bombardment of the much larger particles. It was predicted that charges bound to thermally vibrating molecules would generate electromotive force (emf) at the open terminals of a conductor, and that this placed a limit on the sensitivity of galvanometers. Thermal noise (also called Johnson noise) was first observed by J. B. Johnson at Bell Laboratories in 1927. Figure 73.5 displays white noise as seen in the laboratory on an oscilloscope. FIGURE 73.4 Power transform pairs for white and pink noise. FIGURE 73.5 Thermal noise in a resistor. Figure 73.5 not available