Signal Processing for Communication Systems
Mathuranathan In coherent detection, the receiver derives its demodulation frequency and phase references using a carrier synchronization loop. Such synchronization circuits may introduce phase ambiguity $latex \phi = \hat{\theta}-\theta $ in the detected phase, which could lead to erroneous decisions in the demodulated bits. For example, Costas loop exhibits phase ambiguity of integral multiples of $latex … Read more
Key focus: Complex Baseband Equivalent Models are behavioral models that simplify the simulation, saves computation memory requirements and run time. This article is part of the book Digital Modulations using Matlab : Build Simulation Models from Scratch
For a given modulation technique, there are two ways to implement the simulation model: passband model and equivalent baseband model. The passband model is also called waveform level simulation model. The waveform level simulation techniques, described in this chapter, are used to represent the physical interactions of the transmitted signal with the channel. In the waveform … Read more
Analytic Signal Lab (same on every page in this path) 1. Hilbert / FFT → 2. Envelope & IF → 3. Phase demodulation (you are here) Tools: Hilbert / analytic signal demo Key focus: Demodulation of phase modulated signal by extracting instantaneous phase can be done using Hilbert transform. Hands-on demo in Python & Matlab. … Read more
Extract amplitude envelope, instantaneous phase, and instantaneous frequency via the analytic signal — practical Hilbert/FFT notes.
How the analytic signal and Hilbert transform give envelope and instantaneous phase/frequency, FFT implementation tips, and links to the envelope follow-on.
FIR vs IIR tradeoffs: linear phase, stability, order, and when each wins — with links to digital filter design articles.
The author, Floyd M. Gardner an influential expert in the area of PLLs, has presented a good reference book that encompasses all the theoretical and mathematical concepts for the phase locked loop (PLL) design. The collection of topics in this book provides an excellent source of information to researchers and engineers for understanding and application … Read more
Multipath & PDP (same on every page in this path) 1. Power delay profile → 2. Scattering function → 3. TDL modeling (you are here) Tools: PDP demo · 3GPP TDL A brief intro to modeling a frequency selective fading channel using tapped delay line (TDL) filters. Rayleigh & Rician frequency-selective fading channel models explained. … Read more
Key focus: With examples, let’s estimate and plot the probability density function of a random variable using Matlab histogram function. Generation of random variables with required probability distribution characteristic is of paramount importance in simulating a communication system. Let’s see how we can generate a simple random variable, estimate and plot the probability density function … Read more