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通信原理知识点总结

通信原理知识点总结
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)

?The aperture effect

●Know PPM and PDM

●Quantization

?Quantization noise and (SNR)O of a uniform quantizer (Equ. 3.25-3.33)

●PCM

?Basic concepts

◆Discrete in both time and amplitude

◆Sampling, quantizing, and encoding

?Non-uniform quantizers

◆μ-law and A-law

◆Piecewise linear approximation to the companding circuit

?Five types of line codes and their waveforms

?Differential encoding

?Noise in PCM systems

◆Know that noise including channel noise and quantization noise, and that

performance is essentially limited by the quantization noise

●Concepts of TDM (Fig. 3.19)

●Know the basic concept of digital hierarchy (p.214) and that the basic rate is 64

kbps

●Concepts of DM and delta-sigma modulation

●Concepts of linear prediction and linear adaptive prediction

●DPCM and its processing gain (Equ. 3.82)

Chapter 4

●Two sources of bit errors: ISI and noise

●Matched filter

?Frequency response (Equ. 4.14) and impulse response (Equ. 4.16)

?Properties: the peak SNR dependents only on signal energy-to-noise psd ratio

at the filter input

●Error rate due to noise

?Derivation of Equ. 4.35

?The complementary error function (Equ. 4.29)

?The result with equiprobable input signals (Equ. 4.38-4.40)

●The baseband data transmission system model (Fig. 4.7 and Equ. 4.44-4.48)

●Nyquist’s criterion

?The Nyquist’s criterion (p.262)

?The ideal Nyquist channel (Equ. 4.54-4.56 and Fig. 4.8, 4.9)

?Raised cosine spectrum (Equ. 4.59, Fig. 4.10)

◆The definition of α and the bandwidth B T

●Correlative-level coding (partial response signaling)

?Duobinary signaling (class I partial response)

◆Basic concepts (Fig. 4.11, 4.13, Equ. 4.66, 4.71)

◆The concept of decision feedback

◆Error-propagation and precoding

?Generalized form of correlative-level coding

●Baseband M-ary PAM transmission (Equ. 4.84)

●ADSL (Fig. 4.26)

●Optimum linear receiver

?For linear channel with both ISI and noise

?The MMSE receiver (Equ. 4.110 and Fig. 4.27)

●Adaptive equalization

?The LMS algorithm (Equ. 4.114, 4.115)

?The basic concept of decision-feedback equalization (Fig. 4.32)

Chapter 5

●Geometric representation of signals (Equ. 5.5-5.7 and Fig. 5.3)

?The vector form (Equ. 5.8) and definitions of length, Euclidean distance, and

angle

?Gram-Schmidt orthogonalization procedure

●Conversion of the continuous AWGN channel into a vector channel

?Basic formulations (Equ. 5.28-5.34)

?The vector representation represents sufficient statistics for detection

●Log-likelyhood functions for AWGN channel (Equ. 5.51)

●Maximum likelihood decoding

?The concept of signal constellation

?The maximum likelihood rule (Equ. 5.55), for AWGN channel, the rule is

Equ. 5.59 and 5.61

●Equivalence of correlation and matched filter sampled at time T

●Probability of error

?Know the invariance to rotation and translation

?The concept of the minimum energy signals

?Know how to use union bound to derive a upper bound (p. 332 – 335) (Equ.

5.89)

?Know that there is, in general, no unique relationships between symbol error

probabilities and BER

Chapter 6

●Basic concepts of keying and ASK, FSK, and PSK

●The relationship between baseband and passband power spectral density (Equ.

6.4)

●Bandwidth efficiency (Equ. 6.5)

●The passband transmission model

●Coherent PSK

?BPSK

◆Basic definitions (Equ. 6.8-6.14, Fig. 6.3)

◆Error probability (Equ. 6.20)

?QPSK

◆Basic definitions (Equ. 6.23-6.27)

◆Error probability (Equ. 6.34, 6.38)

◆Generation and detection (Fig. 6.8)

?M-PSK

◆Basic definitions (Equ. 6.46)

◆Bandwidth efficiency

◆Know that the power spectra of M-PSK has no discrete frequency

component

●M-QAM

?Basic definitions (Equ. 6.53-6.55)

?QAM square constellations (Fig. 6.17)

●Coherent FSK

?Coherent BFSK

◆Basic definitions (Sunde’s FSK) (Equ. 6.86-6.91, Fig. 6.25)

◆Error probability (Equ. 6.102)

◆Know that the power spectra of BFSK has discrete frequency

components

?MSK

◆The concept of CPFSK

◆The concept of MSK

◆The phase trellis

◆Signal-space diagram (Fig. 6.29)

◆Error probability (Equ. 6.127)

?Bandwidth efficiency of M-FSK signals

●Noncoherent receivers (Fig. 6.37)

●The reason of envelop detection (Fig. 6.38)

●Error probability of noncoherent receiver (Equ. 6.163)

●Noncoherent BFSK

?Receiver structure (Fig. 6.42)

?Error probability (Equ. 6.181)

●DPSK

?Basic concepts (Fig. 6.43, 6.44)

?Error probability (Equ. 6.184)

●Comparison of digital modulation schemes

?Relationship among the error probabilities (Table 6.8 and Fig. 6.45)

?Bandwidth efficiencies of M-PSK, M-QAM, and M-FSK

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