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SignalProcessing

  

BlackmanWindow

  

multiply a sample by a Blackman windowing function

 

Calling Sequence

Parameters

Options

Description

Thread Safety

Examples

Compatibility

Calling Sequence

BlackmanWindow( A, alpha )

Parameters

A

-

Array of real or complex numeric values; the signal

alpha

-

standard, optimal or a numeric value : (optional) parameter for Blackman windowing function

Options

• 

container : Array, predefined Array for holding results

• 

inplace : truefalse, specifies that output should overwrite input

Description

• 

The BlackmanWindow( A, alpha ) command multiplies the Array A by the Blackman windowing function with parameter alpha and returns the result in an Array having the same length. The length of A must be at least 4.

• 

The Blackman windowing function w is defined as follows for a sample of N elements.

wk=α2+120.5cos2πkN1αcos4πnN12

• 

The default value of the parameter alpha is standard, and in this case, a value of α=−0.16 is assumed. When alpha is optimal, then a value of α=0.51+cos2πN1 is used. The alpha parameter may also take an arbitrary (real) numeric value.

• 

For an Array with complex values, the real and imaginary parts are multiplied by the same windowing function.

• 

Before the code performing the computation runs, A is converted to datatype float[8] or complex[8] if it does not have one of those datatypes already. For this reason, it is most efficient if A has one of these datatypes beforehand. This does not apply if inplace is true.

• 

If the container=C option is provided, then the results are put into C and C is returned. With this option, no additional memory is allocated to store the result. The container must be an Array of the same size and datatype as A.

• 

If the inplace or inplace=true option is provided, then A is overwritten with the results. In this case, the container option is ignored.

Thread Safety

• 

The SignalProcessing[BlackmanWindow] command is thread-safe as of Maple 17.

• 

For more information on thread safety, see index/threadsafe.

Examples

withSignalProcessing:

aGenerateUniform10,1,1

0.78521849215030790.58841396495699970.99316582269966760.92157828854397080.038780170958489240.0136057925410568920.210756972897798160.74960021581500880.138966357801109770.21228513401001725

(1)

BlackmanWindowa

0.00.0299324022457669970.256237280332811460.58059432178270150.0368849788010960150.0129408756342559530.132776892925612820.193397231607525640.0070691675725880750.0

(2)

BlackmanWindowa,'standard'

0.00.0299324022457669970.256237280332811460.58059432178270150.0368849788010960150.0129408756342559530.132776892925612820.193397231607525640.0070691675725880750.0

(3)

BlackmanWindowa,'optimal'

0.01.525409038590391810-170.13764721948808980.495496762124061130.036326461415364650.0127449231282969530.113315818052656850.103890390785033753.60257490260773110-180.0

(4)

cArray1..10,'datatype'='float'8,'order'='C_order':

BlackmanWindowa,'container'=c

0.00.0299324022457669970.256237280332811460.58059432178270150.0368849788010960150.0129408756342559530.132776892925612820.193397231607525640.0070691675725880750.0

(5)

c

0.00.0299324022457669970.256237280332811460.58059432178270150.0368849788010960150.0129408756342559530.132776892925612820.193397231607525640.0070691675725880750.0

(6)

aGenerateTone100,1,1Pi,Pi:

useplotsindisplayArraylistplota,listplotBlackmanWindowa,listplotBlackmanWindowa,'optimal';animatelistplot,'BlackmanWindow'a,α,α=1..1end use

Compatibility

• 

The SignalProcessing[BlackmanWindow] command was introduced in Maple 17.

• 

For more information on Maple 17 changes, see Updates in Maple 17.

See Also

SignalProcessing[BartlettWindow]

SignalProcessing[HammingWindow]

SignalProcessing[HannWindow]

SignalProcessing[KaiserWindow]