Digital signal processing¶
Filtering¶
- class sdr.FIR
Implements a finite impulse response (FIR) filter.
- class sdr.IIR
Implements an infinite impulse response (IIR) filter.
Multirate filtering¶
- class sdr.Interpolator(sdr.FIR)
Implements a polyphase interpolating FIR filter.
-
sdr.multirate_taps(up: int, down: int =
1, ...) NDArray[float_] Computes the multirate FIR filter that achieves rational resampling by \(P/Q\).
- sdr.polyphase_matrix(up: int, down: int, taps: ArrayLike) NDArray
Converts the multirate FIR filter taps \(h_i\) into the polyphase matrix \(H_{i, j}\) that achieves rational resampling by \(P/Q\).
Arbitrary resampling¶
- class sdr.FarrowResampler
Implements a cubic Farrow arbitrary resampler.
Filtering applications¶
- class sdr.Differentiator(sdr.FIR)
Implements a differentiator FIR filter.
- class sdr.Integrator(sdr.IIR)
Implements an integrator IIR filter.
Correlation¶
Signal manipulation¶
-
sdr.mix(x: NDArray, freq: float =
0, ...) NDArray Mixes the time-domain signal \(x[n]\) with a complex exponential or real sinusoid.
- sdr.to_complex_bb(x_r: NDArray[float_]) NDArray[complex_]
Converts the real passband signal \(x_r[n]\) centered at \(f_{s,r}/4\) with sample rate \(f_{s,r}\) to a complex baseband signal \(x_c[n]\) centered at \(0\) with sample rate \(f_{s,c} = f_{s,r}/2\).
- sdr.to_real_pb(x_c: NDArray[complex_]) NDArray[float_]
Converts the complex baseband signal \(x_c[n]\) centered at \(0\) with sample rate \(f_{s,c}\) to a real passband signal \(x_r[n]\) centered at \(f_{s,r}/4\) with sample rate \(f_{s,r} = 2f_{s,c}\).
- sdr.upsample(x: NDArray, rate: int) NDArray
Upsamples the time-domain signal \(x[n]\) by the factor \(r\).
- sdr.downsample(x: NDArray, rate: int) NDArray
Downsamples the time-domain signal \(x[n]\) by the factor \(r\).