blackman — Generate a Blackman window vector in MATLAB and RunMat.
blackman generates a Blackman window from a nonnegative scalar length. The length accepts single, double, or any of the eight built-in integer classes; floating lengths round to the nearest integer.
Syntax
w = blackman(n)
w = blackman(n, sampling)
w = blackman(n, precision)
w = blackman(n, sampling, precision)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
n | SizeArg | Yes | — | Window length. |
sampling | StringScalar | No | "symmetric" | Sampling mode: "symmetric" or "periodic". |
precision | StringScalar | No | "double" | Output precision: "double" or "single". |
Returns
| Name | Type | Description |
|---|---|---|
w | NumericArray | Blackman window column vector. |
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:blackman:InvalidLength | Length input is not a finite nonnegative scalar value. | blackman: expected a nonnegative scalar length |
RunMat:blackman:InvalidOption | An option argument is not a string-like sampling/precision token. | blackman: unrecognized option |
RunMat:blackman:UnknownOption | An option string is not recognized by blackman. | blackman: unrecognized option |
RunMat:blackman:InternalError | Window materialization fails internally. | blackman: internal error |
RunMat:blackman:ArgumentCount | More than a sampling option and an output-type option are supplied. | blackman: too many input arguments |
How blackman works
blackman(L)returns anL x 1symmetric Blackman window.blackman(L, 'periodic')returns the periodic form used in spectral-analysis workflows.blackman(..., 'single')returns a single-precision window;'double'is the default.- Length
Laccepts single, double, int8, int16, int32, int64, uint8, uint16, uint32, or uint64; noninteger floating values round to the nearest integer. - A logical scalar length is available only as an explicitly gated RunMat extension.
blackman(0)returns an empty0 x 1tensor.blackman(1)returns1.- For the symmetric case and
L > 1, coefficients usecospievaluation of0.42 - 0.5*cospi(2*n/(L-1)) + 0.08*cospi(4*n/(L-1)), matching the current enhanced-accuracy algorithm. - The periodic form is constructed by evaluating a symmetric window of length
L + 1and dropping the final sample.
Examples
Generate a short Blackman window
w = blackman(8);
disp(w')Generate a periodic Blackman window
w = blackman(8, 'periodic');
disp(w')Generate a single-precision Blackman window
w = blackman(8, 'single');
class(w)Using blackman with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how blackman changes the result.
Run a small blackman example, explain the result, then change one input and compare the output.
FAQ
Why would I use blackman instead of hann or hamming?⌄
A Blackman window is often used when you want lower spectral leakage at the cost of a wider main lobe. It is a common tradeoff choice in spectral analysis workflows.
What is the difference between the symmetric and periodic Blackman window?⌄
Use the symmetric form for filter-design style workflows. Use 'periodic' for FFT-based spectral analysis, where RunMat constructs a symmetric window of length L + 1 and removes the final sample.
Does blackman support single precision?⌄
Yes. Pass 'single' as the final option to request a single-precision output. The default output type is double precision.
Does an integer length produce an integer window?⌄
No. Every integer length class is a structural input; output is double by default or single when requested explicitly.
Does blackman accept a gpuArray input?⌄
No interactive gpuArray input form exists because the only numeric input is a host scalar length. GPU code generation is a separate documented capability; RunMat may internally materialize the new floating window on its active provider.
Related Math functions
Signal
butter · buttord · cheb2ord · conv · conv2 · deconv · downsample · envelope · filter · filtfilt · fir1 · freqz · gauspuls · hamming · hann · hilbert · periodogram · pulstran · pwelch · rectpuls · resample · 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
bandwidth · isdiag · ishermitian · issymmetric · istril · istriu · symrcm
Optim
coneprog · fminbnd · fminunc · fsolve · fzero · integral · linprog · lsqcurvefit · lsqnonlin · optimoptions · optimset · quad · secondordercone
Ops
cross · ctranspose · dot · mldivide · mpower · mrdivide · mtimes · pagemtimes · pagetranspose · trace · transpose
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