OFDM cyclic prefix length — how long must the CP be? (Matlab demo)
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.
Mathuranathan
FFT magnitude and phase spectrum — how to interpret (and fix noisy phase)
How to get amplitude and phase from an FFT: |X[k]|, atan2, why phase looks noisy, the magnitude threshold fix, Matlab + Python, and links to bins/fftshift and the FFT calculator.
Interpret FFT results — complex DFT, frequency bins, and fftshift
How DFT bins map to Hz, what negative frequencies mean, when to use fftshift/ifftshift, and how this pairs with magnitude/phase plots.
Root Mean Square (RMS) Formula Explained for Signals
What RMS means for voltages and DSP signals, how it ties to average power, and the formulas for continuous and discrete waveforms.
Generate AWGN in Matlab/Octave without awgn() — variance from Eb/N0
Build AWGN from randn without Communications Toolbox: set noise variance from SNR or Eb/N0, generate real/complex noise, verify power.
Gold code generator — preferred pairs, correlation, and CDMA use
How Gold codes are built from preferred m-sequence pairs, their three-valued cross-correlation, and why they are used in CDMA/GNSS spreading.
Auto-Correlation Matrix in Matlab & Python: Toeplitz Form
Build the autocorrelation (covariance) matrix R from snapshots in Matlab or NumPy — including complex conjugate correlation — for Wiener, LMS, and MVDR beamformers.
QAM Modulation using Karnaugh-map walks
This article focused on constructing constellation for rectangular QAM modulation using Karnaugh-map walks. Exploit inherent property of Karnaugh-maps to construct Gray coded QAM constellation points. M-ary Quadrature Amplitude Modulation (M-QAM): qam modulation In MQAM modulations, the information bits are encoded as variations in the amplitude and the phase of the signal. The M-QAM modulator transmits … Read more
MIMO System Capacity: Unlocking Blazing-Fast Wireless Speeds
MIMO — Capacity path 1. Intro → 2. Channel model → 3. SISO capacity → 4. Ergodic SISO → 5. MIMO capacity Tools: Shannon calculator Introduction Extend the scalar ergodic average to a matrix channel. With receiver CSI and equal power across transmit antennas, ergodic MIMO capacity is the expectation of a log-determinant—the expression Telatar … Read more
Understanding Ergodic Capacity: Testing Your Wireless Speed Calculator
MIMO — Capacity path 1. Intro → 2. Channel model → 3. SISO capacity → 4. Ergodic SISO → 5. MIMO capacity Tools: Shannon calculator Introduction We already met ergodic capacity as an expectation. Now treat it as something you compute: how do you estimate it stably, and is there a closed form to check … Read more