Signal Processing for Communication Systems
Pulse-shaping Lab path:Nyquist zero-ISI → Raised cosine → Matched filter + SRRC → Eye diagramsTool: RRC filter & bandwidth calculator As mentioned earlier, the shortcomings of the sinc pulse can be addressed by making the transition band in the frequency domain less abrupt. The raised-cosine (RC) pulse comes with an adjustable transition band roll-off parameter … Read more
Key focus: Sinc pulse shaping of transmitted bits, offers minimum bandwidth and avoids intersymbol interference. Discuss its practical considerations & simulation. Sinc pulse shaping As suggested in the earlier post, the pulse shape that avoids ISI with the least amount of bandwidth is a sinc pulse of bandwidth $latex F_{sym}/2$. Here, $latex F_{sym}=1/T_{sym}$ is the … Read more
m-sequences from linear feedback shift registers: period 2ⁿ−1, two-level autocorrelation, and their role as parents of Gold codes.
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
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.
Build the analytic signal with Hilbert or FFT, extract envelope and instantaneous phase/frequency — Matlab, Python, and an interactive Hilbert demo.
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
Turn a Matlab histogram into an estimated PDF: normalize by sample count and bin width, then overlay normpdf / theoretical densities for Gaussian, Rayleigh, and exponential checks.
How long should the OFDM cyclic prefix be? CP must cover the channel delay spread so the FFT sees circular convolution — Matlab hands-on plus overhead calculator.