Communication principle of 80 1

80 1 outline for the postgraduate entrance examination of communication principles:

First, the examination requirements

Students are required to master the basic concepts of communication theory, the basic working principle and performance analysis method of communication system, and have strong ability to analyze and solve problems.

Second, the examination content

1, deterministic signal and random signal analysis

Determine the correlation function and energy (power) spectral density of signal and random signal; Hilbert transform, analytic signal, bandpass signal and bandpass system; Zero mean stationary Gaussian process; Gaussian white noise, narrowband stationary Gaussian process, matched filter.

2. Analog modulation

Basic principles, modulation and demodulation methods, spectrum characteristics and anti-noise performance of analog linear modulation (DSB-SC, AM, SSB); The basic principle of analog angle modulation (PM, FM), the relationship between FM and PM, Carson formula, FM anti-noise performance; Frequency division multiplexing.

3. Digital baseband transmission

Power spectral density of digital baseband signal and PAM signal; Common line code type; Matched filtering reception of digital baseband signals in AWGN channel: intersymbol interference, Nyquist criterion, raised cosine roll-off, optimal baseband system, eye diagram; The basic concept of channel equalization; Binary partial response system of the first kind.

4. Frequency band transmission of digital signals

Basic principles, modulation and demodulation methods, power spectral density and bit error rate of binary digital modulation (OOK, 2FSK, 2PSK, 2PSK); Principle, power spectral density, bit error rate and symbol bit error rate of QPSK and OQPSK; Signal space and optimal reception theory; The constellation diagram, modulation and demodulation block diagram and power spectral density of MASK, MPSK and MQAM, as well as the error rate analysis of MASK and rectangular constellation MQAM; Gray mapping; Constellation, spectrum and symbol error rate characteristics of MFSK.

5. Source and source code

Information entropy and mutual information; Huffman encoding; Low-pass and band-pass sampling theorems: the concepts of quantization and quantization signal-to-noise ratio, uniform quantization, optimal quantization, A-law thirteen-line coding; Time division multiplexing.

6. Channel and channel capacity

Distortionless channel; Fading channels (coherence bandwidth, coherent time, delay spread, Doppler spread); Definition of channel capacity, BSC channel capacity, AWGN channel capacity.

7. Channel coding

Basic concepts of channel coding, error correction and detection, hamming weight and hamming distance; Generation matrix and supervision matrix of linear block code, decoding and hamming code of linear block code; Basic concepts, generating polynomials and generating matrices of cyclic codes; Cyclic redundancy check; Coding and Viterbi decoding of convolutional codes.

8, spread spectrum communication, multiple access communication, multi-carrier modulation

Generation, properties and autocorrelation characteristics of m-sequence: Walsh code and its characteristics; The principle, power spectral density and anti-jamming performance of direct sequence BPSK: code division multiplexing and CDMA: the basic concept of rake reception: scrambling code; Basic principle of OFDM, cyclic prefix, peak-to-average ratio, carrier frequency offset.

Third, the examination paper structure

Multiple choice questions, calculation questions, drawing questions, etc.