Network analyzer

The spectrometer supports phase cycling, asynchronous sequence implementation, and parameter-array experiments. Thus, most standard solid-state NMR experiments are feasible, including CPMAS, multiple-pulse H decoupling such as TPPM, 2D experiments, multiple-quantum NMR, and so on. In addition, the focus of development is on its extension of, or modification to, the hardware and/or the software, in the spirit of enabling the users to put their own new ideas into practice. In this paper, several examples of such have been described. They include the compact NMR and MRI systems, active compensation of RF pulse transients, implementation of a network analyzer, dynamic receiver-gain increment,31 and so on. 

Dielectric constant (DE) values are reported as permittivity with the symbol e or K The polymer cylindrical donuts were used for the measurement of DE on a Hewlett-Packard 8510 automated network analyzer. The analyzer is capable of measuring 401 data points over a frequency band of 500 MHz to 18.5GHz. Typically Sll and S21 values, which correspond to reflection and transmission, respectively, are measured and then these values are used to calculate the permittivity and permeability. 

The microwave source used in this study was a microwave network analyzer model IFR 6845 shown in Fig. 15.2b (Microwave network analyzer). Integrated into this single instrument is a synthesized source, a three-input scalar analyzer, and a synthesized spectrum analyzer. Complete engineering details of this equipment is beyond the scope of this document, but the basic function of this instrument is to generate a constant... 

Fig. 15.2b IFR6845 series microwave network analyzer used as the synthesized source to generate and feed the microwaves into the resonant cavities (See Color Plates)...

Microwave network analyzer purchased through Naval Grant number - ONR-N00013-03-0880... 

Network Analyzer Replaced with miniaturized electronics, as shown in fig. 7... 

Paddison et al. performed high frequency (4 dielectric relaxation studies, in the Gig ertz range, of hydrated Nafion 117 for the purpose of understanding fundamental mechanisms, for example, water molecule rotation and other possible processes that are involved in charge transport. Pure, bulk, liquid water is known to exhibit a distinct dielectric relaxation in the range 10—100 GHz in the form of an e" versus /peak and a sharp drop in the real part of the dielectric permittivity at high / A network analyzer was used for data acquisition, and measurements were taken in reflection mode. 

For most of the circuits, the transient response of the filter is matched to hardware results. For a select few filters, a network analyzer is utilized to measure the frequency response of the filter. 

The simulation results do not correlate well to the hardware. A possible cause is the ESR of a Mallory TDC106K505WSG 10 /U.F capacitor, C2. The feedback loop is originated at the collector of the PNP transistor to avoid sensitivity to the output capacitor s ESR. However, investigation into the poor correlation indicates that the circuit is sensitive to the ESR of capacitor C2. The ESR was measured using an HP 3577A network analyzer. The results are shown in Fig. 4.25. 

The network analyzer described above can measure both the impedance and its reciprocal, the admittance, Y = V, 6, or in the complex notation, Y = Y + iY"... 

A method which circumvents many of the disadvantages of the transmission line and cavity perturbation technique was pioneered by Stuchley and Stuchley (1980). This technique calculates the dielectric parameters from the microwave characteristics of the reflected signal at the end of an open-ended coaxial line inserted into a sample to be measured. This technique has been commercialized by Hewlett Packard with their development of a user-friendly software package (Hewlett Packard 1991) to be used with their network analyzer (Hewlett Packard 1985). This technique is outstanding because of its simplicity of automated execution as well as the fact that it allows measurements to be made over the entire frequency spectrum from 0.3 MHz to 20 GHz. 

The sensors are available as a stand-alone entity for R D and development purposes and can be utilized with any network analyzer operating over the frequency range from 0.5 GHz to 10 GHz. KDC can also provides a cost-effective network analyzer with internal software to calibrate microwave parameters against process parameters. Custom design programs to meet specific applications can also be undertaken. Sensor costs are on the order of 3,000 KDC network analyzers cost approximately 24,000. 

As has been indicated, the sensor can be adapted to almost any process application. The sensor is designed to withstand pressures to 300 psi and can be designed to withstand process temperatures as high as 450° C using sapphire window materials. Accuracies between 0.01 an 0.5 % are typical. Sensitivities to 0.01% have been obtained and are primarily limited by the sophistication of the network analyzer utilized. 

Hewlett Packard 1985. Measuring Dielectric Constant with the h/p 8510 Network Analyzer. Product Note 8510-3. Hewlett Packard Corp., Palo Alto, CA. 

The advantage of network analysers is the possibility of impedance measurement near resonance with evaluation of the parameters R, L, C and C0 and test of the equivalent electrical circuit. However frequency response and network analysers are relatively slow with 1-10 s per measurement in typical experiments. A new generation of faster instruments has come to the market like the HP E5100 Network Analyzer with 40 (is per point in the impedance spectrum which allows us to obtain the impedance of the system in less than 10 ms. 

Figure 13.7 shows a set of crystal impedance spectra as a function of time (coverage) during electroprecipitation of a PVF film. These measurements were made using a network analyzer in reflectance mode, as described previously [41]. For the long deposition times employed here, the film is relatively thick. Furthermore, there is appreciable solvent incorporation. These two factors mean that there will be considerable shear deformation of the film as a result of crystal oscillation. 

Measurements in distributed circuit methods are commonly made with network analyzers (Roussy and Pearce, 1995). 

Network analyzer An instrument that provides a controlled-amplitude signal to the input of a test device or circuit over a range of frequencies, then... 

Figure 6.7 (a) Diagram of the use of a network analyzer as used to measure one-port frequency response for a TSM resonator, (b) Measurement of one-port frequency response using a synthesized oscillator source together with a vector voltmeter and a pair of directional couplers. 

Two-port devices include SAW, FPW, and APM delay lines and the two-port-resonator variations of these devices. For all the delay lines, the transmitted signal S]2 (between ports) is most important Just as in one-port measurements, a network analyzer is the instrument of choice to measure frequency response the setup is depicted in Figure 6.9(a) (page 362). Frequency response can also be measured using the synthesized oscillatorA VM combination shown in Figure 6.9(b). As for the one-port measurements, this setup is most convenient when computer controlled. 

Figure 6.9 (a) Use of a network analyzer to measure two-port-device frequency response. (b) Setup for measuring two-port frequency response using the synthesized os-cillatorA VM combination. 

One-port FPW measurements, typically using a network analyzer, yield the input impedance of the transducer, the real and imaginary components of which can be used to determine the density and viscosity of a fluid contacting the device. 

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