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Z2 = (m 2 + n 2)(m 2 + n 2)

Example 4.2 now shows how to find a distribution minimizing Fisher information. We have to distinguish two cases.

(b) Coupling and Decoupling Networks. Coupling and decoupling devices are required for appropriate coupling of a disturbing signal over the entire frequency range of interest, with a defined common-mode impedance at the EUT port or various cables of the EUT. These CDNs can be combined into one assembly. The primary specification for the output impedance of the CDN is defined for two frequency ranges: 150 kHz 26 MHz 26 80 MHz 150 150 20 + 60

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therefore controlled by the control voltage through the variation of the varactor s capacitance. Generally, the characteristics of a varactor are functions of frequency. Therefore, the variation of capacitance vs. control voltage must be carefully measured and evaluated as the frequency is varied. Fortunately, it has been found that such a frequency dependence for actual varactors is very small and within the range of experimental error. The values shown in Figure 6.24 are applicable for the frequency range to be covered. In other words, within experimental error, they are independent of frequency. The test results for four varactors are shown in Figure 6.24. Varactor 1 might be applied for cases when the VCO is operated in the low-frequency range, since its capacitances on the range of control voltages are higher, while varactor 2 might be applied for cases when the VCO is operated in the high-frequency range since its capacitances on the range of control voltages are relatively lower. Varactor 3 seems to be the overall best candidate because its variation of capacitance vs. control voltage, C/ (CV), is higher than that of either varactor 1 or 2. Varactor 4 is a poor candidate because its variation of capacitance vs. control voltage, C/ (CV), changes too much over the range of the control voltage. The slope C/ (CV) is too steep when the control voltage is low whereas it is too at when the control voltage is high.

This mixer is a conventional mixer with a 250 MHz IF. The linear gain of a mixer is usually low, only a few decibels. The purpose of the mixer is to change the frequency of the information carrying signal from RF to IF, where achieving the desired gain and selectivity is easy. However, knowledge of the mixer gain is necessary so that the gain requirements of the IF ampli er can be determined. An important RF characteristic of a mixer is its 1 dB compression point, where signi cant nonlinear effects begin to occur. These nonlinear effects create many spurious signals that should be avoided. In an ampli er, the linear gain and 1 dB compression can be measured easily over a range of frequencies with a VNA. This measurement is not possible on a mixer with a standard VNA, because the input and output signals are at different frequencies. (Some VNAs have special modi cations to make swept mixer measurements over a limited range of input power.) The easiest way to measure the linear gain and 1 dB compression point of a mixer is to use a signal generator and a spectrum analyzer. A test setup for making this measurement is provided in Figure 24.9. The same setup was used for the upconverter measurement of 18 except that the input signal is an RF signal in mixer

Inner Product without Weighting. To compute the reciprocal basis 0 = [e,,. . . ,e,] the relationships (3.70), (3.56) and (3.65) are used, which can be written as

Fig. 12.6 The fact that we can find the centroid of very complicated shapes suggests that we might approximate a curved region (such as in Fig. 12.6) by a set of rectangles and so construct its centroid approximately, by straight edge alone. This requires, however, something we have not yet considered. How do we construct a set of rectangles The least equipment that we require is set-square, to provide us with right angles, and a parallel rule (as in Fig. 12.7) so that we can draw