Signal Processing for Communication Systems
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
QPSK maps two bits per symbol on four phases; how modulation/demodulation work, constellation geometry, and links to BER tools and BPSK/M-PSK.
Digital Modulations 101 — 5 lessons (same on every page in this path) 1. BPSK → 2. QPSK → 3. M-PSK sim (you are here) → 4. QAM sim → 5. EVM Tools: BER vs Eb/N0 · EVM → SNR · Eb/N0 ↔ SNR Side reading for Digital Modulations 101. Use this comparison after QPSK … Read more
BPSK maps bits to opposite phases; coherent demodulation, decision rule, and links to the Q-function BER formula and interactive calculator.