Digital Signal Processing¶

TinyDSP — Signal Processing for Edge Devices

TinyDSP wraps and extends ESP-DSP for edge devices, adding SHM-specific algorithms not found in ESP-DSP.

TinyMath → Math / Matrix / DotProduct
TinyDSP → all remaining DSP modules + DWT / ICA / Resample

Architecture¶

Signal Processing

tiny_conv · Convolution
tiny_corr · Correlation
tiny_resample · Resampling

Convolution → Correlation → Resample →
Digital Filtering

tiny_fir · FIR (window design)
tiny_iir · IIR (bilinear transform)

FIR → IIR →
Signal Transforms

tiny_fft · FFT/IFFT spectrum analysis
tiny_dwt · Discrete Wavelet Transform
tiny_ica · ICA (C++ API)

FFT → DWT → ICA →
Debug Support

tiny_view · ASCII waveform plot
tiny_view · Spectrum · Statistics

Support →

Use Case Index¶

Dominant frequency

→ FFT — tiny_fft_find_peak_frequency
Denoising / Smoothing

→ FIR / DWT
Source separation

→ ICA — ICA::decompose (C++)
Delay estimation

→ Cross-correlation — tiny_ccorr_f32
Template matching

→ Sliding correlation — tiny_corr_f32
Sample rate conversion

→ Resampling — tiny_resample_f32
Time-frequency analysis

→ DWT — tiny_dwt_multilevel_decompose_f32
Headless debugging

→ Support — tiny_view_signal_f32

Quick Start¶

#include "tiny_dsp.h"

void app_main(void) {
    tiny_fft_init(1024);                        // one-time init

    float data[1024] = { /* sensor data */ };
    float spectrum[2048];                       // [Re0,Im0,Re1,Im1,...]

    tiny_fft_f32(data, 1024, spectrum,          // windowed FFT
                 TINY_FFT_WINDOW_HANNING);

    float freq, mag;
    tiny_fft_find_peak_frequency(               // find dominant freq
        spectrum, 1024, 100.0f, &freq, &mag);
}

ESP32 Speedup¶

Function	DSP Backend	Speedup
`tiny_conv_f32`	`dsps_conv_f32`	2–4×
`tiny_fft_f32`	`dsps_fft2r_fc32`	3–5×
`tiny_fir_filter_f32`	`dsps_fir_f32`	2–3×
`tiny_corr_f32`	`dsps_corr_f32`	2–4×

Non-ESP32 platforms fall back to pure C; API is identical.

Module Dependencies & Code Tree¶

tiny_math  ──►  signal/  ──►  filter/  ──►  transform/  ──►  support/
                 │                            │
                 └── FIR uses convolution      └── ICA depends on Mat class

include/    tiny_dsp.h / tiny_dsp_config.h
signal/     conv · corr · resample
filter/     fir · iir
transform/  fft · dwt · ica (C++)
support/    view