ChirpZT
Advanced Analysis Library Only
AnalysisLibErrType ChirpZT (double inputSequence[], ssize_t numberOfElements, NIComplexNumber startingPoint, NIComplexNumber increment, int algorithm, ssize_t 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 | double [] | The input sequence. |
| numberOfElements | ssize_t | The length of inputSequence. |
| startingPoint | NIComplexNumber | The point at which to begin evaluating the Chirp-Z Transform. |
| increment | NIComplexNumber | The increment between each point to evaluate for the Chirp-Z Transform. |
| algorithm | int | The method to use to compute the Chirp-Z Transform. algorithm must be one of the following values:
|
| numberOfBins | ssize_t | The length of transform. If numberOfBins is less than 1, this function uses numberOfElements for this parameter. |
| Output | ||
| Name | Type | Description |
| transform | NIComplexNumber [] | 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. |
Additional Information
Library: Advanced Analysis Library
Include file: analysis.h
LabWindows/CVI compatibility: LabWindows/CVI 8.0 and later