1. Chapter 1 Introduction to Electronics
1.1 Signals
1.2 Frequency Spectrum of Signals
1.3 Analog and Digital Signals
1.4 Amplifiers
1.5 Circuit Models for Amplifiers
1.6 Frequency Response of Amplifiers
1.7 Digital Logic Inverters
1.8 Circuit Simulation Using SPICE
2018年11月8日
J. Chen

2. 1.1 Signals Parameter in the real world Transducer Electrical signal
𝑣 𝑠 (𝑡)
𝑇𝑖𝑚𝑒, 𝑡
Parameter
in the real world
Transducer
传感器/换能器
Electrical signal
(a) Thévenin form
(b) Norton form
Signal sources
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J. Chen

3. 1.2 T & F-domain expression and spectrum
Sine-wave: temporally and spatially determined by Amplitude, Frequency/Period and Phase 0
(rad/s)
Sine-wave voltage signal and its spectrum
2018年11月8日
J. Chen

4. 1.2 T & F-domain expression and spectrum
Time-varying signal in arbitrary form→FT→sum of sine-waves.
e.g. symmetrical square-wave
𝑽𝐬𝐢𝐧 𝒙
𝑽 (𝐬𝐢𝐧 𝒙+ 𝟏 𝟑 𝐬𝐢𝐧 𝟑𝒙)
𝑽(𝐬𝐢𝐧 𝒙+ 𝟏 𝟑 𝐬𝐢𝐧 𝟑𝒙 + 𝟏 𝟓 𝐬𝐢𝐧 𝟓𝒙)
𝑽(𝐬𝐢𝐧 𝒙+ 𝟏 𝟑 𝐬𝐢𝐧 𝟑𝒙 +…+ 𝟏 𝟐𝟓 𝐬𝐢𝐧𝟐 𝟓𝒙)
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5. 1.2 T & F-domain expression and spectrum
Sine-wave is always used for analysis, design and testing.
Frequency spectrum of the periodic square wave
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J. Chen

6. 1.2 T & F-domain expression and spectrum
Spectra of some typical signals
(Hz) A
Spectrum of CWDM signal
𝑓(𝐺𝐻𝑧)
𝑃 0 (𝑚𝑊)
Spectrum of Human Voice
Spectrum of laser signal
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7. 1.3 Signals: analog v.s. digital
Delay evolution over 24 hours in a optical fiber system for Time/Frequency transfer AD DA
Code format of the standard IRIG-B(DC)
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8. 1.4 Amplifiers
Electronic circuits can perform many analog and digital signal processing functions
This course mainly deals with the simplest but most important function—— Amplification
Direction of signal flow
(a) Circuit symbol
(b) With a common terminal (ground)
2018年11月8日
J. Chen

9. 1.4 Amplifiers
Both voltage and current can be amplified. Hence there are different types, depending on the practical application scenery.
Source, Input and output resistances
The gain (V/V, A/A, V/A, A/V)
For a particular amplifier, some gains may be less than one. However, the signal power is certainly amplified.
2018年11月8日
J. Chen

10. 1.4 Amplifier: types and key issues
Signal intension (small signal amp., power amp., …)
Signal spectrum (wideband amp., tuned amp.,...) …
Key issues
Gain, input/output resistance, …
Bandwidth
Linear & Nonlinear distortion, Saturation
…..
2018年11月8日
J. Chen

11. 1.4 Power supplies and Biasing
DC sources are required, not only to bias the circuit for appropriate operation, but also to provide power
(a) An amplifier with two dc supplies
(b) Usual form(Simplified)
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12. 1.4 Units & Decibel
Decibel (dB): a dimensionless number in logarithmic scale.
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13. 1.4 Units & Decibel
e.g. The lowest audible intensity is about I0=10-12（W/m2）；In general, the sound intensity is expressed in dB in relative to I0 as:
The maximum sound intensity human beings can bear is about 1（W/m2）, or 120dB。
2018年11月8日
J. Chen

14. 1.4 Symbol convention DC: Uppercase, AC: Lowercase e.g.
Total instantaneous quantity, 𝑖 𝐸
Incremental signal quantity, 𝑖 𝑒
DC component, 𝐼 𝐸
Power supply, 𝐼 𝐸𝐸 , 𝑉 𝐸𝐸
Amplitude of a sine wave, 𝐼 𝑒
e.g.
𝑖 𝐸
𝑖 𝑒
𝐼 𝐸
𝐼 𝑒
2018年11月8日
J. Chen

15. 1.5 Circuit models for amplifiers
Mathematical description of the device physical characteristics, useful in quantitative analysis.
(a) Circuit model for the voltage amplifier
(b) The voltage amplifier with input signal source and load
2018年11月8日
J. Chen

16. 1.5 Circuit models for amplifiers
Different device has its own model.
A device may have few different models according to the purpose, precision, applications, etc..
(a) Small-signal circuit model for a bipolar junction transistor (BJT)
(b) An alternative small-signal circuit model for the BJT
(c) BJT model for high frequency analysis
2018年11月8日
J. Chen

17. 1.6 Frequency response of amplifiers
The band of frequencies, over which the gain is almost constant (within 3 dB) is called the amplifier bandwidth.
3dB
Typical magnitude response of an amplifier
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J. Chen

18. 1.6 Frequency response of amplifiers
Frequency response of amplifiers can be evaluated using Basic Circuit Theory
Single-Time-Constant (STC) Networks
(a) a low-pass network
(b) a high-pass network
Two examples of STC networks
2018年11月8日
J. Chen

19. 1.6 Frequency response of amplifiers
Single-Time-Constant (STC) Networks
low-pass
high-pass
(a) Magnitude
(b) Phase response
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20. 1.6 Frequency response of amplifiers
Classification of amplifiers based on frequency response.
(a) Capacitively coupled amplifier
(b) Direct-coupled amplifier
𝑓(𝐺𝐻𝑧)
𝑃 0 (𝑚𝑊)
(c) Tuned or bandpass amplifier
2018年11月8日
J. Chen

21. 1.7 Digital logic inverters
Out of scope
Those, who are going to be engaged in the R&D of electronic circuit related areas, are advised to read the content.
Especially, attention should be paid to Power Dissipation and Propagation Delay.
2018年11月8日
J. Chen

22. Chapter 2 Operational Amplifiers
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23. Operational Amplifiers
The Gain
open-loop gain.
closed-loop gain
differential gain
The terminals
inverting input terminal(反相输入端)
noninverting input terminal(同相输入端)
The Common mode rejection(共模抑制比)
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J. Chen

24. End of Chapter 1 & 2
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25. Home work
1.2, 1.15, 1.17, 1.23, 1.31, 1.58
2018年11月8日
J. Chen