ENEX351
Communication Systems
Syllabus
- Introduction (5 hours)
- Review of signals and systems
- Block diagram of analog and digital communication systems
- System needs and requirements
- Noise, attenuation, and interference
- Amplitude Modulation (8 hours)
- Time domain expressions, frequency domain representation, modulation index, signal bandwidth of amplitude modulated signal
- AM for single and double tone message, carrier and sideband components, power in carrier and sideband components, bandwidth and power efficiency, Hilbert transform
- Double sideband AM (DSB-FC), generation (Square law), detection (Envelope and square law method)
- Double sideband suppress carrier (DSB-SC), generation (Linear modulator, balance modulator), Synchronous detection method
- Overview of SSB, VSB, and ISB modulations
- Phase locked loop (PLL), demodulation of AM using PLL
- Super-heterodyne AM receiver
- Angle Modulation (7 hours)
- Basic definition, time domain expression for frequency modulation (FM) and phase modulation (PM)
- Time domain expression for single tone, modulated FM signals, spectral representation
- Bandwidth of FM, Carson's rule, narrow and wideband FM
- Generation of FM: Direct and indirect
- Demodulation of FM signals: Non-synchronous (Limiter discriminator) and synchronous (PLL)
- Stereo FM, spectral details, pre-emphasis and de-emphasis network
- Super-heterodyne Radio receiver for FM
- Pulse Modulation (8 hours)
- Sampling theorem, ideal sampling, practical sampling, aliasing effect, aperture effect, signal reconstruction
- Fundamentals of PAM, PWM, and PPM, time domain representation
- Pulse coded modulation (PCM), quantization, quantization error, quantization noise
- Signal to quantization noise ratio (SQNR) in uniform quantization, SQNR improvements, non-uniform quantization, companding techniques (A-law, mu-Law)
- DPCM, DM: Encoder, decoder, advantage, disadvantage, noise in DM
- Multiplexing Techniques (3 hours)
- Multiplexing fundamentals: FDM, TDM, WDM and applications
- T1 and E1 TDM PCM telephony hierarchy
- Multiple access fundamentals: FDMA, TDMA, CDMA, SDMA
- Baseband Digital Data Transmission (8 hours)
- Information theory, measurement of information, entropy, symbol rates and data rates
- Shannon Hartley channel capacity theorem, implication of theorem, and theoretical limits
- Compression techniques: Shannon-Fano, Huffman codes
- Line coding schemes: Unipolar, polar, bipolar
- RZ, NRZ, AMI, Manchester, differential Manchester, B8ZS, HDB3 for digital data transmission
- ISI, Nyquist criteria, pulse shaping for zero ISI
- Digital Modulation Techniques (8 hours)
- Binary digital modulation (ASK, FSK, PSK), generation, properties, constellation diagram and detections
- QPSK generation, properties, constellation diagram, and detections
- M-ARY modulation techniques, M-PSK versus M-QAM
- Error Detection and Correction Coding (7 hours)
- Hamming weight, hamming distance, code vectors, constraint length, code rate, syndromes
- Error detection and correction: error detection codes (Checksum, CRC); error correction codes (Linear block codes, hamming codes)
- Cyclic codes (Generator polynomial, parity-check polynomial)
- Noise in Communication Systems (6 hours)
- Definition, white noise, AWGN channel, PSDF, and AC function of white noise
- Ideal low-pass and RC filtering of white noise, noise equivalent bandwidth of a filter
- Optimum detection of a pulse in additive white noise, the matched filter, realization of matched filters (Time correlators), the matched filter for a rectangular pulse
- Overview of error probability function in digital communication (ASK, FSK, and PSK)
Practicals
- Review of different Signals using MATLAB
- Amplitude modulation generation and reconstruction
- Frequency modulation generation and reconstruction
- Pulse modulation generation and reconstruction
- Digital modulation ASK generation and reconstruction
- Digital modulation FSK generation and reconstruction
- Conversion of the given binary sequence into different line coding
- PCM generation and reconstruction
- DPCM and DM: Generation and detection
- FDM and TDM: Multiplexing and demultiplexing