doppler-dsp 0.4.0

Dead-simple, ultra-fast digital signal processing.

doppler

Dead-simple, ultra-fast digital signal processing.

doppler is a C99 DSP library: NCO, FIR filter, FFT, polyphase resampler, DDC, and ZMQ-based signal streaming. Python and Rust wrap the same C core — no second implementation, no divergence, full SIMD throughput from any language.

Why it's built this way

Every algorithm lives in C exactly once. The Python layer is type conversion and lifetime bridging — a few hundred lines of glue, not a reimplementation. Bugs get fixed once, benchmarks reflect real hardware, and a C transmitter talks to a Python subscriber without surprises.

Performance

On a Ryzen 7 AI 350 (-O2): NCO raw accumulator ~15 GSa/s, LO CF32 ~1.8 GSa/s, FIR CF32 ~900 MSa/s, FFT CF32 (N=4096) ~180 MSa/s, polyphase resampler (2× decim) ~70 MSa/s. Run make bench to measure on your hardware.

Quick start

Python

from doppler.spectral import FFT
import numpy as np

X = FFT(1024).execute(np.random.randn(1024).astype(np.complex64))

C

#include "fft/fft_core.h"

dp_fft_t *fft = dp_fft_create(1024, -1, 1);
dp_fft_execute_cf32(fft, in, 1024, out);
dp_fft_destroy(fft);

Build

jbx install-deps        # install system deps (detects OS/distro)
make                    # C library
make pyext              # + Python bindings
make test               # CTest suite
make bench              # benchmarks

Docs

Full docs at doppler-dsp.github.io/doppler — Quick Start, Architecture, API Reference, Examples.

Licensing

MIT. The default build uses pocketfft (BSD-3-Clause). Build with -DUSE_FFTW=ON for FFTW (LGPL).