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Contents

getFilters

System object: dsp.DigitalDownConverter
Package: dsp

Get handles to decimation filter objects

Syntax

S = getFilters(H)
getFilters(H,'Arithmetic',ARITH)

Description

S = getFilters(H) returns a structure, S, with copies of the filter System objects and the CIC normalization factor that form the decimation filter cascade. The ThirdFilterStage structure field is empty if the third filter stage has been bypassed. The CIC normalization factor equals the inverse of the CIC filter gain. In some cases, this gain includes a correction factor to ensure that the cascade response meets the ripple specifications.

getFilters(H,'Arithmetic',ARITH) specifies the arithmetic of the filter stages. You can set ARITH to double, single, or fixed-point. When object H is in an unlocked state, you must specify the arithmetic input. When object H is in a locked state, the arithmetic input is ignored.

When H is in an unlocked state, and you specify the arithmetic as fixed-point, the getFilters method returns filter System objects. The custom coefficient data type properties of these System objects are set to the values that the dsp.DigitalDownConverter System object™ uses to process data when you call the step method. All other fixed-point properties are set to their default values.

When H is in a locked state, and the input to the step method is of a fixed-point data type, the getFilters method returns filter System objects. All fixed-point properties of these System objects are set to the exact values that the dsp.DigitalDownConverter System object uses to process the data.

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