A Simplified Matlab Function for Power Spectral Density
In an earlier post, I showed how to compute power spectral density (PSD) of a discrete-time signal using the Matlab function pwelch. Pwelch is a useful function because it gives the correct output, and it has the option to average multiple Discrete Fourier Transforms (DFTs). However, a typical function call has five arguments, and it can be hard to remember how to set them all and how they default.
In this post, I create a simplified PSD function by putting a wrapper on pwelch that sets some parameters and converts the output units from W/Hz to dBW/bin. The function is named psd_simple.m, and its code is listed in the appendix.
Summary
This article presents a compact MATLAB wrapper, psd_simple.m, that simplifies the use of pwelch to compute power spectral density (PSD). Readers will learn how the wrapper sets sensible defaults and converts pwelch output from W/Hz to dBW/bin, making PSD calls easier to use and interpret for practical signal analysis.
Key Takeaways
- Use the psd_simple.m wrapper to compute PSDs with a simpler function call and built-in sensible defaults.
- Convert pwelch output from W/Hz to dBW/bin and interpret per-bin PSD values correctly.
- Choose appropriate window, overlap, and NFFT settings to manage frequency resolution and variance trade‑offs.
- Apply the simplified PSD function to real signals (audio, radar, communications) and extract noise floor or SNR estimates.
Who Should Read This
Signal processing engineers, MATLAB users, and graduate students who compute PSDs for audio, radar, or communications signals and want a simpler, ready-to-use pwelch wrapper.
Still RelevantIntermediate
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