RF Communication Engineering

Introduction to Rf circuits: History, Applications, Frequency Range, Generations of cell phone radio, Analog vs Digital Systems, IC technologies, Linearity - Memoryless vs with Memory systems, Time variance vs time invariance, Harmonics, Gain Compression, Intermodulation, Impact on Tx and Rx chains, Nyquist signaling, OFDM, Memory Polynomials, MOSFET example of nonlinearity, Noise - Statistical ensembles, Autocorrelation, PSD, Thermal Noise, Noise in resistors, Input referred noise, MOSFET examples of noise, Noise Figure, Optimum source impedance, Noise Figure circles, 1/f Noise, shot noise, Sensitivity, Dynamic Range, SFDR. Mobile RF communication - Cellular Concept, Fading, FD/TD, FDMA/TDMA/CDMA, Walsh Coding, Frequency Hopping SS, Modulation - AM/FM, circuits for modulation/demodulation, ASK/FSK/PSK, basis functions, Constellation diagram, Matched filters/Correlators for optimal detection, Coherent vs Noncoherent detection, Carrier synchronization for coherent detection, SNR vs BER, M-ary Modulation/Demodulation, MSK, GMSK, Raised Cosine filtering, Power efficient vs spectrally efficient modulation, Heterodyne Receivers - Importance of nonlinearities, Selectivity vs sensitivity in receivers, the concept of image frequency, choosing IF, the problem of Half IF, Homodyne receivers - Comparison with Heterodyne receivers, Quadrature mixing, I/Q mismatch, Effect of IIP2, Effect of 1/f noise, Image Reject mixers - Concept of complex Fourier Transform, Hartley, Weaver architecture, Digital IF Receivers - Nyquist Rate ADC-based receivers, sampling and sub-sampling receivers, Effect of ADC noise on sensitivity, Transmitters - Homodyne, Heterodyne transmitters, Injection Pulling in Tx, RF receiver circuits - Low Noise Amplifier, LNA performance metrics, Stability, Gain circles, NF circles, Stability Circles, Absolute stability vs potential instability, CS, CE LNA, Cascode LNA, Noise cancelling LNA, N Path filtering LNA, Mixers, Concept of mixing/multiplying signals, Mixer performance metrics, SSB vs DSB NF, Unbalanced, Single Balanced and Double Balanced mixers, Mixer Linearity, Mixer Noise, RF Transmitter Circuits - Power Amplifier performance metrics, Class A - F-1 amplifiers, concept of efficiency of PA, techniques to improve efficiency, impact of harmonics on efficiency, Source side and Load side load Space, Gain circles, Load Pull Analysis, PA linearization using Analog/Digital techniques, Oscillator and PLL - Barkhausen and Kurokawa conditions for oscillation, Oscillator stability, Startup and Nyquist test, Performance metrics, Phase noise, Effect of Phase Noise on Rx and Tx, Phase noise models - linear non linear perturbation, Oscillator topologies, VCO, Injection locking, PLL components - PFD, charge pump, Type 1 and Type 2 PLL, Effect of Phase noise on PLL noise, Brief Introduction to Integer N and Fractional N PLL. The RF transmitter circuits, oscillator and PLL Lectures will be supplemented by discussions on the research done in these circuits at IIT Bombay.