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

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 2018年11月8日 J. Chen

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

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) 2018年11月8日 J. Chen

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 2018年11月8日 J. Chen

1.2 T & F-domain expression and spectrum Spectra of some typical signals 0 500 1000 1500 2000 2500 3000 (Hz) A Spectrum of CWDM signal 𝑓(𝐺𝐻𝑧) 𝑃 0 (𝑚𝑊) Spectrum of Human Voice Spectrum of laser signal 2018年11月8日 J. Chen

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) 2018年11月8日 J. Chen

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

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

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

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) 2018年11月8日 J. Chen

1.4 Units & Decibel Decibel (dB): a dimensionless number in logarithmic scale. 2018年11月8日 J. Chen

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

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

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

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

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 2018年11月8日 J. Chen

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

1.6 Frequency response of amplifiers Single-Time-Constant (STC) Networks low-pass high-pass (a) Magnitude (b) Phase response 2018年11月8日 J. Chen

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

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

Chapter 2 Operational Amplifiers 2018年11月8日 J. Chen

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) 2018年11月8日 J. Chen

End of Chapter 1 & 2 2018年11月8日 J. Chen

Home work 1.2, 1.15, 1.17, 1.23, 1.31, 1.58 2018年11月8日 J. Chen