resample — Resample a signal by a rational factor with FIR antialiasing.
y = resample(x,p,q) changes the sample rate of x by the rational factor p/q. RunMat designs a Kaiser-windowed FIR antialiasing filter by default, compensates the filter delay, and operates along the first non-singleton dimension unless Dimension is specified.
Syntax
Y = resample(X, P, Q)
Y = resample(X, P, Q, N)
Y = resample(X, P, Q, N, BETA)
Y = resample(X, P, Q, B)
[Y, B] = resample(X, P, Q, ___)
[Y, B] = resample(X, P, Q, B, ___)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
X | Any | Yes | — | Input signal array. |
P | NumericScalar | Yes | — | Positive integer upsampling factor. |
Q | NumericScalar | Yes | — | Positive integer downsampling factor. |
N | NumericScalar | No | 10 | Half-length filter order factor. |
BETA | NumericScalar | No | 5 | Kaiser window shape parameter. |
B | NumericArray | No | — | FIR antialiasing filter coefficients. |
B | NumericArray | Variadic | — | FIR antialiasing filter coefficients. |
Returns
| Name | Type | Description |
|---|---|---|
Y | NumericArray | Resampled signal. |
B | NumericArray | FIR antialiasing filter coefficients used for resampling. |
Returned values from resample depend on how many outputs the caller requests.
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:sampleRate:ArgCount | Required arguments are missing or more than three inputs are provided. | sample-rate builtin: expected X, N, and optional PHASE |
RunMat:sampleRate:InvalidInput | X is not numeric, logical, complex, or a gpuArray containing numeric values. | sample-rate builtin: X must be numeric or logical |
RunMat:sampleRate:InvalidFactor | N is not a finite positive integer scalar. | sample-rate builtin: N must be a positive integer scalar |
RunMat:sampleRate:InvalidPhase | PHASE is not an integer scalar in the range 0 <= PHASE < N. | sample-rate builtin: PHASE must be an integer scalar with 0 <= PHASE < N |
RunMat:sampleRate:GatherFailed | A gpuArray input cannot be gathered for host sample-rate conversion. | sample-rate builtin: failed to gather GPU input |
RunMat:sampleRate:SizeOverflow | The requested output shape overflows host allocation limits. | sample-rate builtin: requested output is too large |
RunMat:sampleRate:BuildOutput | Output tensor construction fails. | sample-rate builtin: failed to build output |
RunMat:sampleRate:InvalidOption | A sample-rate conversion option, filter vector, or dimension selector is invalid. | sample-rate builtin: invalid option |
RunMat:sampleRate:OutputCount | More outputs are requested than the builtin supports. | sample-rate builtin: too many output arguments |
How resample works
- Signal input
Xaccepts documented single and double real or complex numeric arrays; native typed-integer signal storage is rejected before provider dispatch. pandqmust be finite positive integer scalars; the ratio is reduced before filter design and output sizing.- The output size along the operated dimension is
ceil(size(x,dim) * p / q); all other dimensions are preserved. resample(x,p,q,n)uses a Kaiser-windowed FIR filter with2*n*max(p,q)+1taps after ratio reduction.resample(x,p,q,n,beta)usesbetaas the Kaiser window shape parameter.resample(x,p,q,b)uses a caller-supplied real FIR coefficient vector.[y,b] = resample(...)returns the resampled signal and the FIR coefficients used.Dimension,dimresamples along an explicit one-based dimension.- Typed-integer
p,q, filter-length, Kaiser-beta, filter-vector, and dimension controls are RunMat extensions. They are decoded structurally or checked for exact double representability as their role requires, and MATLAB compatibility mode rejects them before gathering. - Timetable and nonuniform time-vector syntaxes are not implemented yet; use
interp1/timetable-specific workflows before rational resampling when those forms are needed.
Examples
Upsample a row vector by a rational factor
x = 1:5;
y = resample(x, 3, 2)Return the filter coefficients
[y,b] = resample(x, 4, 1, 8, 5)Resample along columns
Y = resample(X, 2, 1, Dimension=2)Using resample with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how resample changes the result.
Run a small resample example, explain the result, then change one input and compare the output.
FAQ
Which dimension does resample use?⌄
By default RunMat follows MATLAB's first non-singleton dimension rule. Use the Dimension name-value option to select a specific dimension.
Can I provide my own antialiasing filter?⌄
Yes. Pass a real coefficient vector as the fourth argument, for example resample(x,p,q,b).
Does resample support nonuniform time vectors or timetables?⌄
Not yet. This implementation covers the uniform rational-rate signal forms and rejects unsupported time/timetable forms rather than returning a misleading result.
Related Math functions
Signal
blackman · butter · buttord · cheb2ord · conv · conv2 · deconv · downsample · envelope · filter · filtfilt · fir1 · freqz · gauspuls · hamming · hann · hilbert · periodogram · pulstran · pwelch · rectpuls · sawtooth · sinc · spectrogram · square · tripuls · unwrap · upsample · zplane
Elementwise
abs · angle · bsxfun · complex · conj · double · erf · erfcinv · exp · expm1 · factorial · flintmax · gamma · gammaln · heaviside · hypot · idivide · imag · intmax · intmin · ldivide · log · log10 · log1p · log2 · minus · nextpow2 · plus · pow2 · power · rdivide · real · realmax · realmin · realsqrt · rescale · sign · single · sqrt · swapbytes · times · typecast · uint16 · uint32 · uint8
Trigonometry
acos · acosh · asin · asinh · atan · atan2 · atanh · cos · cosd · cosh · cospi · deg2rad · pol2cart · rad2deg · sin · sind · sinh · sinpi · tan · tand · tanh
Reduction
all · any · bounds · cummax · cummin · cumprod · cumsum · cumtrapz · diff · gradient · max · maxk · mean · median · min · mink · movmax · movmean · movmedian · movmin · movprod · movstd · movsum · movvar · nnz · prod · rms · std · sum · trapz · var
Structure
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Optim
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Ops
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Open-source implementation
Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how resample is executed, line by line, in Rust.
- View the source for resample in Rust on GitHub
- Learn how the RunMat runtime works
- Found a bug? Open an issue with a minimal reproduction.
About RunMat
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