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.
RMS (root mean square) value — meaning, formula, and signal power
What RMS means for voltages and DSP signals, how it ties to average power, and the formulas for continuous and discrete waveforms.
Invitation to Submit your work for publication at gaussianwaves.com
Since you have landed on this page, probably you are looking for an opportunity to write for this website. I assume that you have looked around and you know that I take this website seriously. I am committed to adding value to my readers and to you as an author. I am currently accepting guest posts from … Read more
Physical Telepresence : The future of communication.
We live in the age of smart phones that can be loaded with numerous applications to communicate with each other. What’s next ? Where do we go from here ? Students at MIT Media Labs has answered the call with a novel approach of “Physical Telepresence” that provides the ability to remotely render shapes of … Read more
Generate AWGN in Matlab/Octave without awgn() — variance from SNR
Create AWGN manually: set noise variance from SNR or Eb/N0, generate real/complex noise, and verify power — links to BER tools.
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.
Construct autocorrelation Matrix in Matlab & Python
Auto-correlation, also called series correlation, is the correlation of a given sequence with itself as a function of time lag. Cross-correlation is a more generic term, which gives the correlation between two different sequences as a function of time lag. Given two sequences $latex x$ and $latex y$, the cross-correlation at times separated by lag … Read more
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) In MQAM modulations, the information bits are encoded as variations in the amplitude and the phase of the signal. The M-QAM modulator transmits a series … Read more
Capacity of MIMO system over fading Channels
MIMO / Capacity Lab path:MIMO overview → Characterize MIMO channels → SISO capacity → Ergodic SISO capacity → MIMO capacityTool: Shannon–Hartley capacity calculator As reiterated in the previous article, a MIMO system is used to increase the capacity dramatically and also to improve the quality of a communication link. Increased capacity is obtained by spatial … Read more
Ergodic Capacity of SISO flat fading channel
MIMO / Capacity Lab path:MIMO overview → Characterize MIMO channels → SISO capacity → Ergodic SISO capacity → MIMO capacityTool: Shannon–Hartley capacity calculator Understand ergodic capacity of a SISO flat-fading system over fading channels. Model and simulate capacity curves in Matlab. Channel model In the previous post, derivation of SISO fading channel capacity was discussed. … Read more