electronic communications: a systems approach beasley | hymer | miller copyright © 2014 by pearson...
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![Page 1: Electronic Communications: A Systems Approach Beasley | Hymer | Miller Copyright © 2014 by Pearson Education, Inc. All Rights Reserved Noise Designation](https://reader035.vdocuments.mx/reader035/viewer/2022081420/56649f325503460f94c4e825/html5/thumbnails/1.jpg)
Electronic Communications: A Systems ApproachBeasley | Hymer | Miller
Copyright © 2014 by Pearson Education, Inc.All Rights Reserved
Noise Designation and Calculation
• Signal-to-Noise Ratio Measure of desired signal power to noise
power.• Noise Figure
Specifies exactly how noisy a device is.• Reactance Noise Effects
Reactive circuits do limit frequency response; significant effect on noise characteristics.
![Page 2: Electronic Communications: A Systems Approach Beasley | Hymer | Miller Copyright © 2014 by Pearson Education, Inc. All Rights Reserved Noise Designation](https://reader035.vdocuments.mx/reader035/viewer/2022081420/56649f325503460f94c4e825/html5/thumbnails/2.jpg)
Electronic Communications: A Systems ApproachBeasley | Hymer | Miller
Copyright © 2014 by Pearson Education, Inc.All Rights Reserved
Figure 1-12 Noise figure versus frequency for a 2N4957 transistor.(Used with permission from SCILLC dba ON Semiconductor. All rights reserved.)
![Page 3: Electronic Communications: A Systems Approach Beasley | Hymer | Miller Copyright © 2014 by Pearson Education, Inc. All Rights Reserved Noise Designation](https://reader035.vdocuments.mx/reader035/viewer/2022081420/56649f325503460f94c4e825/html5/thumbnails/3.jpg)
Electronic Communications: A Systems ApproachBeasley | Hymer | Miller
Copyright © 2014 by Pearson Education, Inc.All Rights Reserved
Noise Designation and Calculation
• Noise Created by Amplifiers in Cascade Friiss’s formula• Overall noise effect of multistage system
![Page 4: Electronic Communications: A Systems Approach Beasley | Hymer | Miller Copyright © 2014 by Pearson Education, Inc. All Rights Reserved Noise Designation](https://reader035.vdocuments.mx/reader035/viewer/2022081420/56649f325503460f94c4e825/html5/thumbnails/4.jpg)
Electronic Communications: A Systems ApproachBeasley | Hymer | Miller
Copyright © 2014 by Pearson Education, Inc.All Rights Reserved
Noise Designation and Calculation
• Equivalent Noise Temperature Means of representing noise produced at
output of real-world device or system. Noise generated by resistor placed at
input to noiseless amplifier with the same gain as device or system under consideration.
![Page 5: Electronic Communications: A Systems Approach Beasley | Hymer | Miller Copyright © 2014 by Pearson Education, Inc. All Rights Reserved Noise Designation](https://reader035.vdocuments.mx/reader035/viewer/2022081420/56649f325503460f94c4e825/html5/thumbnails/5.jpg)
Electronic Communications: A Systems ApproachBeasley | Hymer | Miller
Copyright © 2014 by Pearson Education, Inc.All Rights Reserved
Noise Designation and Calculation
• Equivalent Noise Resistance Manufacturers represent noise
generated by a device with a fictitious resistance.
![Page 6: Electronic Communications: A Systems Approach Beasley | Hymer | Miller Copyright © 2014 by Pearson Education, Inc. All Rights Reserved Noise Designation](https://reader035.vdocuments.mx/reader035/viewer/2022081420/56649f325503460f94c4e825/html5/thumbnails/6.jpg)
Electronic Communications: A Systems ApproachBeasley | Hymer | Miller
Copyright © 2014 by Pearson Education, Inc.All Rights Reserved
Figure 1-13 Noise contours for a 2N4957 transistor.(Used with permission from SCILLC dba ON Semiconductor. All rights reserved.)
![Page 7: Electronic Communications: A Systems Approach Beasley | Hymer | Miller Copyright © 2014 by Pearson Education, Inc. All Rights Reserved Noise Designation](https://reader035.vdocuments.mx/reader035/viewer/2022081420/56649f325503460f94c4e825/html5/thumbnails/7.jpg)
Electronic Communications: A Systems ApproachBeasley | Hymer | Miller
Copyright © 2014 by Pearson Education, Inc.All Rights Reserved
Troubleshooting
• General Troubleshooting Techniques Ask the right questions. Take time to learn test equipment, its
capabilities, and limitations. Maintain clear, up-to-date records of all
changes made to equipment. Replace suspicious unit with known
good one. Plot a game plan or strategy.
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Electronic Communications: A Systems ApproachBeasley | Hymer | Miller
Copyright © 2014 by Pearson Education, Inc.All Rights Reserved
Troubleshooting
• Reasons Electronic Circuits Fail Complete failures Intermittent faults Poor system performance Induced failures
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Electronic Communications: A Systems ApproachBeasley | Hymer | Miller
Copyright © 2014 by Pearson Education, Inc.All Rights Reserved
Troubleshooting
• Troubleshooting Plan Symptoms as clues to faulty stages Signal tracing and signal injection Voltage and resistance measurements Substitution
![Page 10: Electronic Communications: A Systems Approach Beasley | Hymer | Miller Copyright © 2014 by Pearson Education, Inc. All Rights Reserved Noise Designation](https://reader035.vdocuments.mx/reader035/viewer/2022081420/56649f325503460f94c4e825/html5/thumbnails/10.jpg)
Electronic Communications: A Systems ApproachBeasley | Hymer | Miller
Copyright © 2014 by Pearson Education, Inc.All Rights Reserved
Figure 1-14 Signal injection.
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Electronic Communications: A Systems ApproachBeasley | Hymer | Miller
Copyright © 2014 by Pearson Education, Inc.All Rights Reserved
Figure 1-15 Signal tracing.