# CxChirpZT

Advanced Analysis Library Only

AnalysisLibErrType CxChirpZT (NIComplexNumber inputSequence[], int numberOfElements, NIComplexNumber startingPoint, NIComplexNumber increment, int algorithm, int numberOfBins, NIComplexNumber transform[]);

## Purpose

The Chirp-Z Transform calculates the z transform along a spiral in the z-plane at the following points:

for k = 0, 1, ..., M - 1, where M is numberOfBins, A is startingPoint, and W is increment.
The DIRECT method computes the Chirp-Z Transform as follows:

for k = 0, 1, ..., M - 1.
The DIRECT form can be reformulated with the convolution, as follows:

where . The convolution operation can be performed in the FREQ_DOMAIN method, which uses an FFT-based technique.

## Parameters

Input
Name | Type | Description
inputSequence | complex number array | The input sequence.
numberOfElements | integer | The length of inputSequence.
startingPoint | complex number | The point at which to begin evaluating the Chirp-Z Transform.
increment | complex number | The increment between each point to evaluate for the Chirp-Z Transform.
algorithm | integer | The method to use to compute the Chirp-Z Transform. algorithm must be one of the following values: DIRECT (0) FREQ_DOMAIN (1)
numberOfBins | integer | The length of transform.
Output
Name | Type | Description
transform | complex number array | The Chirp-Z Transform of sequence inputSequence.

## Return Value

Name | Type | Description
status | AnalysisLibErrType | A value that specifies the type of error that occurred. Refer to analysis.h for definitions of these constants.