embedded-dsp

A high-performance #![no_std] Rust Digital Signal Processing library designed for microcontrollers (Cortex-M, RISC-V, AVR, Xtensa), bare-metal DSP, and real-time audio/sensor pipelines.

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Highlights

• #![no_std] First: Pure core compatibility with zero heap allocations.
• Fixed & Float Parity: CMSIS-style f32, f64, q7, q15, q31, strongly-typed Q15/Q31 newtypes, and the polymorphic DspSample trait.
• Hardware Acceleration: ARM Cortex-M assembly intrinsics (smlad, smlald, ssat, qadd16) via cortex-m-dsp, with portable SWAR vector fallbacks.
• Pure-Integer CORDIC Engine: Shift-and-add sin, cos, atan2, polar conversion, and sqrt requiring no hardware multipliers.
• Streaming Pipelines: Zero-allocation DspNode composable processing chains (Chain, Gain, Limiter).
• Production Tested: Continuous integration across 6 bare-metal architectures (thumbv6m, thumbv7em, thumbv7em-hf, riscv32imc, wasm32, x86_64).

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Module Overview

Category	Key Algorithms & Structs
Filtering & Design	FIR, Biquad IIR (DF-I & Transposed DF-II), LMS/NLMS, Butterworth/Chebyshev design, Windowed-Sinc, $L_\infty/L_2$ SOS Quantization & SQNR analysis, DC Blocker.
Spectral & Transforms	CFFT, RFFT (packed), Block Floating-Point FFT (cfft_bfp_q15/q31), Real Cepstrum, DCT-IV, FWHT, Haar, Hartley, Daubechies-4 DWT, Welch & Burg AR PSD.
Audio & Voice	Goertzel tone detector, Mel & Generalized filterbanks, MFCC, Q15 VAD, Dynamics Compressor with soft knee, Noise Gate.
Control & Power	FOC current/speed PID, Clarke & Park transforms, SOGI-PLL (grid synchronization/resolvers), Costas Loop carrier recovery.
Sensor Fusion & Spatial	Square-Root Kalman Filter (SquareRootKalmanFilter), EKF, 2D Spatial/Vision (Sobel, Median, DCT-II), Delay-and-Sum Beamformer, GCC-PHAT TDoA locator.
Multi-rate & Resampling	CIC Decimator/Interpolator with bit-growth normalization, Polyphase Decimation & Interpolation (Float & Q15), fractional linear resampler.
Math, CORDIC & Windows	CORDIC engine, Complex math, Fast math, Quaternions, 9 Window functions (Kaiser-Bessel with $I_0(\beta)$, Flat-top), G.711 $\mu$-law/A-law companding.

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Quick Start

Add to your Cargo.toml:

[dependencies]
# Standard std environment (all modules enabled)
embedded-dsp = "0.4.1"

# Bare-metal #![no_std] with libm
embedded-dsp = { version = "0.4.1", default-features = false, features = ["libm", "full"] }

# Minimal firmware footprint (only FIR/Biquad filtering + basic math)
embedded-dsp = { version = "0.4.1", default-features = false, features = ["libm", "filtering", "basic-math"] }

Basic Example

use embedded_dsp::*;

fn main() {
    // 1. Fixed-Point Saturating Addition
    let a = [20000i16, 25000];
    let b = [15000i16, 10000];
    let mut out = [0i16; 2];
    add_q15(&a, &b, &mut out); // [32767, 32767] (clamped at i16::MAX)

    // 2. Biquad Filter Cascade
    let coeffs = biquad_lowpass_coeffs(1000.0, 48000.0, core::f32::consts::FRAC_1_SQRT_2);
    let mut filter = BiquadCascade::<5, 4>::new(coeffs);
    let input = [1.0f32, 0.5, -0.2, 0.1];
    let mut filtered = [0.0f32; 4];
    filter.process(&input, &mut filtered);

    // 3. Robust Square-Root Kalman Sensor Filter
    let mut kf = KalmanFilter1D::new(0.0, 1.0, 0.01, 0.1);
    kf.predict(0.0);
    let _est = kf.update(10.2);

    // 4. In-Place FFT
    let mut fft_buf = [0.0f32; 128]; // 64 complex pairs [re, im, ...]
    cfft_f32(&mut fft_buf, 64, 0, 1);
}

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Cookbook & Examples

Need copy-paste code for real-world projects? Check the embedded-dsp Cookbook:

• Motor Control: Sensorless Field-Oriented Control (FOC) with Clarke/Park and Space-Vector PWM.
• Real-Time Audio DMA: DC-Blocker + Biquad Peaking EQ + Peak Limiter streaming pipeline.
• Machine Health: Vibration spectrum analysis and bearing fault detection using Burg AR PSD.
• Multi-rate ADC: High-speed Cascaded Integrator-Comb (CIC) decimation.
• Acoustic Edge AI: Voice Activity Detection (VAD) & MFCC feature extraction.
• Streaming Pipeline: Composing modular DspNode signal processing chains.

Run any included example directly with cargo:

cargo run --example basic_usage
cargo run --example motor_control_foc
cargo run --example audio_speech_pipeline
cargo run --example sensor_fusion_navigation
cargo run --example filter_workbench_and_analysis
cargo run --example spectral_radar_transforms
cargo run --example spatial_vision_processing
cargo run --release --example perf_comparison

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License

Dual-licensed under either MIT or Apache-2.0 at your option. See LICENSE-MIT and LICENSE-APACHE.