通信原理知识点总结

Outline

2012.5

Chapter 0

●

Basic elements of communication systems (p.2) ●

Primary communication resources (p.3) ●

The mobile radio channel (p.18) ●

Block diagram of digital communication system (p.22) ●

Shannon ’s information capacity theorem (p.23-24)

Chapter 1

●

Definition and basic concepts of random process ●

Stationary and non-stationary ●

Mean, correlation, and covariance functions, the mean-square value and variance ●

The concept of ergodic process ● Transmission of a random process through a linear time-invariant filter ⏹ ⎰∞

∞--=τττd t X h t Y )()()( ⏹ The mean, autocorrelation function, and mean-square value of Y ●

Power spectral density ⏹ Definition (Equ. 1.38) ⏹ Input-output relation (Equ. 1.39) ⏹ Einstein-Wiener-Khintchine relations (Equ. 1.42, 1.43) ⏹ Properties ●

Gaussian process (Equ. 80) ●

Concept of white noise ●

Representation of narrowband noise ⏹ The canonical form (Equ. 1.100) ⏹ Properties of the in-phase and quadrature components (p. 65-66) ⏹ Representation using envelop and phase components (Equ. 1.105-1.107) ⏹ Basic concepts of Rayleigh distribution and Rician distribution ● Uncorrelated and statistically independent (p.58)

⏹ Uncorrelated: Covariance is 0

⏹ Statistically independent: defined by joint probability density function

Chapter 2

● Concepts of amplitude modulation and angle modulation (FM and PM) ● AM

⏹ AM signal (Equ. 2.2 and Fig. 2.3), and the amplitude sensitivity k a

⏹ Conditions of correct detection (p. 90)

⏹Spectrum of AM wave (Equ. 2.5 and Fig. 2.4)

⏹Transmission bandwidth B T = 2W

⏹Virtues and limitations of AM

●Linear modulation schemes

⏹The general form (Equ. 2.7)

⏹DSB

◆DSB signal (Equ. 2.8 and Fig. 2.5)

◆Spectrum of DSB wave (Equ. 2.9 and Fig. 2.6)

◆Coherent receiver

◆Basic knowledge of costas receiver

◆Basic concept of quadrature-carrier multiplexing

⏹Basic concepts of SSB and VSB

●Concepts of mixer (Fig. 2.16)

●Concepts of FDM

●Definitions of angle modulation

●FM

⏹ A nonlinear modulation process

⏹Single-tone FM modulation

◆Definitions of ∆f, β

◆Basic knowledge of narrowband and wideband FM

⏹Transmission bandwidth

◆Carson’s rule (Equ. 2.55)

◆Know the universal curve

⏹Demodulation

◆Frequency demodulation (a direct method) (Fig. 2.30)

◆Know phase-locked loop (an indirect method)

●Definitions of SNR’s

⏹(SNR)I, (SNR)O, and (SNR)C

⏹Figure of merit (Equ. 2.81)

●Comparison of figure of merits between DSB-SC (Equ. 2.88) and AM (Equ. 2.95) ●Basic concepts of threshold effect of AM (p.138) and FM systems (p.149) Chapter 3

●Sampling

⏹Definitions of the sampling period and sampling rate

⏹Instantaneous sampling and the ideal sampled signal (Equ. 3.1-3.3, Fig. 3.2)

⏹Derivation of the interpolation formula (Equ. 3.4-3.9)

⏹The sampling theorem and definitions of Nyquist rate and Nyquist interval

⏹The methods of combat aliasing effect (p.187)

●PAM

⏹The difference between PAM and natural sampling

⏹The concept of “sample and hold”

⏹The PAM signal (Equ. 3.10-3.19)