ELEC5403_Lab_3 - ELEC5403 LAB 3 Single Stub Tuning OBJECTIVE In this experiment you will measure the impedance and the reflection coefficient of a

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1 ELEC5403 LAB 3 Single Stub Tuning OBJECTIVE In this experiment you will measure the impedance and the reflection coefficient of a nominal 24-ohm low frequency load resistor at different microwave frequencies using a network analyzer HP 8753A, and also match the load impedance to 50 ohms at a single frequency of 500 MHz using single-stub tuning techniques. Introduction The system, an HP 8753A network analyzer measures the complex one port reflection coefficient S11 or simply r. Calibration of the instrument is done with a standard open load, a standard short load and a standard 50-ohm load. Recalibration is required before measurement if the settings are changed on the instrument. This system uses real time analog signal processing exclusively. Measurements can be done over wide frequency sweeps (linear frequency sweep from 0.3 MHz - 3 GHz) to see overall trends and then individual frequency points (CW frequency) examined for details. By plotting the component input impedance on a Smith Chart we can rapidly match the component to 50 ohms. This involves selecting the correct lengths of transmission lines to act as impedance transforming elements. Equipment Required Spectrum Analyser Slotted Line Signal Generator with internal modulator and attenuation Stubs, Coax Network Analyser HP 8753A TDR
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2 PART A Network analyser Calibration Procedure. Turn on the instrument. 1. Press "PRESET" on the front panel. Connect the standard OPEN load and press the softkey "open". After the "open" calibration, change the load to the standard SHORT load and press the softkey "short". After the "short" calibration, change the load to the standard 50-ohm load and press softkey "load". After the calibration press "DONE at the bottom and then "SAVE". Now the calibration data are saved in register 1 on the instrument. To recall this state at any time, press "recall" on the front panel softkey. NOTE The "PRESET" state sweeps over the full range of frequencies of the 8753A from 300 kHz to 3 GHz. The instrument needs to be recalibrated,if the operating frequency is changed. or a smaller frequency span is selected. If a measurement is to be done at a single specific frequency you should input the same START and STOP frequency. PART B - 1. Connect a nominal 24-ohm resistor to port 1 and look at the frequency response of this resistor on the Smith chart. To quantitatively measure the impedance of this resistor as a function of frequency, you need a frequency marker. Press "mrk" on the front panel ~ "marker mode menu" softkey ~ "smith mkr menu" softkey ~ "R+jX mkr" softkey. The marker (an arrow) should appear on the screen. The real part (R) and imaginary part (X) of the impedance Z = R +jX and the frequency appear on the top of the screen. Turn the large knob on the front panel to change the frequency. The equivalent
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This note was uploaded on 04/25/2010 for the course ELEC 5403 taught by Professor Kumar during the Spring '10 term at Birla Institute of Technology & Science.

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ELEC5403_Lab_3 - ELEC5403 LAB 3 Single Stub Tuning OBJECTIVE In this experiment you will measure the impedance and the reflection coefficient of a

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