When one end of a transmission line is connected to a broadband noise generator, sharp peaks are visible in the cross-correlation function of the signals at both ends of the line. The speed of the electromagnetic waves can be deduced from the time when the peaks appear. The method is suitable for introducing the concepts of cross-correlation functions and noise analysis in an undergraduate physics laboratory.
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I stored the acquired signal using the USB flash memory connection of the oscilloscope. Alternatively, the oscilloscope can be controlled directly from a computer via a USB connection. Depending on the software version and settings, the two channels may be acquired in sequence, not simultaneously, thus destroying the expected temporal correlation.
11.
See www.tti-arb.com.
© 2011 American Association of Physics Teachers.
2011
American Association of Physics Teachers
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