Bw_BPF
Advanced Analysis Library Only
AnalysisLibErrType Bw_BPF (double inputArray[], ssize_t numberOfElements, double samplingFrequency, double lowerCutoffFreq, double upperCutoffFreq, int order, double outputArray[]);
Purpose
Filters the input array using a Butterworth bandpass digital filter. Bw_BPF can perform the operation in place; that is, the input and output arrays can be the same.
Example Code
/* Generate a random signal and filter it using a fifth-order bandpass Butterworth filter. The pass band is from 200.0 to 300.0. */
double x[256], y[256], fs, fl, fh;
ssize_t n;
int status, order;
n = 256;
fs = 1000.0;
fl = 200.0;
fh = 300.0;
order = 5;
Uniform (n, 17, x);
status = Bw_BPF (x, n, fs, fl, fh, order, y);
Parameters
| Input | ||
| Name | Type | Description |
| inputArray | double [] | Array containing the raw data to filter. |
| numberOfElements | ssize_t | Number of elements in both the input and output array. |
| samplingFrequency | double | The frequency in Hertz at which you want to sample inputArray. This value must be greater than 0. |
| lowerCutoffFreq | double | Lower cutoff frequency in Hertz. This value must be 0 < lowerCutoffFreq < upperCutoffFreq < 0.5 * samplingFrequency. |
| upperCutoffFreq | double | Upper cutoff frequency in Hertz. This value must be 0 < lowerCutoffFreq < upperCutoffFreq < 0.5 * samplingFrequency. |
| order | int | Filter order. This value must be greater than 0. Default Value: 5. |
| Output | ||
| Name | Type | Description |
| outputArray | double [] | Filtered data. |
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 3.1 and later
Example
Refer to apps\freqresp\freqresp.cws for an example of using the Bw_BPF function.