ECE312_lec06

3rd Year, Faculty of Eng. at Shoubra
lec#6, Electronic Circuits (A)

Transcript

1. Lecture # 6 General Frequency Considerations Instructor: Dr. Ahmad El-Banna Benha University Faculty of Engineering at Shoubra November 2014 ECE-312 Electronic Circuits (A) © Ahmad El-Banna
2. Agenda Introduction Logarithms and Decibels General Frequency Considerations Normalization Process 2 © Ahmad El-Banna ECE-312 , Lec#6 , Nov 2014
3. INTRODUCTION 3 © Ahmad El-Banna ECE-312 , Lec#6 , Nov 2014
4. Introduction 4 ECE-312 , Lec#6 , Nov 2014 © Ahmad El-Banna • The analysis thus far has been limited to a particular frequency. • We will now investigate the frequency effects introduced by the larger capacitive elements of the network at low frequencies and the smaller capacitive elements of the active device at high frequencies. • Because the analysis will extend through a wide frequency range, the logarithmic scale will be defined and used throughout the analysis. • In addition, because industry typically uses a decibel scale on its frequency plots, the concept of the decibel is introduced.
5. LOGARITHMS AND DECIBELS 5 © Ahmad El-Banna ECE-312 , Lec#6 , Nov 2014
6. Logarithms 6 ECE-312 , Lec#6 , Nov 2014 © Ahmad El-Banna • We use it to cover a wide range.
7. Semi-log graph paper 7 ECE-312 , Lec#6 , Nov 2014 © Ahmad El-Banna
8. Decibels 8 ECE-312 , Lec#6 , Nov 2014 © Ahmad El-Banna • Human Auditory Response ! • t • t • t
9. GENERAL FREQUENCY CONSIDERATIONS 9 © Ahmad El-Banna ECE-312 , Lec#6 , Nov 2014
10. Low, High & Mid Frequency Range 10 ECE-312 , Lec#6 , Nov 2014 © Ahmad El-Banna • The larger capacitors of a system will have an important impact on the response of a system in the low-frequency range and can be ignored for the high-frequency region. • The smaller capacitors of a system will have an important impact on the response of a system in the high-frequency range and can be ignored for the low-frequency region. • The effect of the capacitive elements in an amplifier are ignored for the mid-frequency range when important quantities such as the gain and impedance levels are determined.
11. Typical Frequency Response 11 ECE-312 , Lec#6 , Nov 2014 © Ahmad El-Banna The band frequencies define a level where the gain or quantity of interest will be 70.7% of its maximum value.
12. NORMALIZATION PROCESS 12 © Ahmad El-Banna ECE-312 , Lec#6 , Nov 2014
13. 13 ECE-312 , Lec#6 , Nov 2014 © Ahmad El-Banna • Phase plot • Decibel plot • Normalized plot
14. • For more details, refer to: • Chapter 9 at R. Boylestad, Electronic Devices and Circuit Theory, 11th edition, Prentice Hall. • The lecture is available online at: • http://bu.edu.eg/staff/ahmad.elbanna-courses/11966 • For inquires, send to: • ahmad.elbanna@feng.bu.edu.eg 14 ECE-312 , Lec#6 , Nov 2014 © Ahmad El-Banna