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Unformatted text preview: EE/BIOE 497e PROBLEM SET 4 DUE: 2 May 2008 Problem 1: (34 points) Figure 1 shows the widely used method introduced by Lowe and Tarr in 1968 (distributed in class) for coupling the RF power amplifier and preamplifier to a nuclear resonance probe. The transmission lines in Figure 1 are short enough that electrical losses may be neglected. The transmission lines have characteristic impedance of 50 Ω and β = ω √ LC = π 50 rad/m at 1 MHz. Figure 1: Method for coupling the spectrometer receiver and transmitter to a probe. 1. (11 points) Suppose that you are using the spectrometer in Figure 1 to detect a proton resonance ( 1 H) using a static magnetic field with flux density B o = 1.5 Tesla. What is the length, in meters, of the quarter-wavelength line between points A and B in Figure 1? 2. (11 points) Now suppose the block diagram in Figure 1 is part of a QR system (just eliminate the magnet) for detecting the explosive 1,2-bis[(nitroxy)methyl]-1,3-propanediol-dinitrate, C 5 H 8 N 4 O 12 , commonly known as pentaerythritol tetranitrate, or PETN for short. (The terrorist Richard Reid hid 10 ounces of PETN-based material, a version of the plastic explosive C4 that is very sensitive to heat and friction, in each of his shoes when he boarded Flight 63 in Paris on December 22, 2001.) In order to detect the transition in PETN at 890 kHz using the system in Figure 1, what must be the length of the quarter-wavelength line in meters?kHz using the system in Figure 1, what must be the length of the quarter-wavelength line in meters?...
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This note was uploaded on 07/23/2008 for the course EE 497e taught by Professor Unknown during the Spring '08 term at Penn State.
- Spring '08