https://github.com/berndporr/iirj
An efficient IIR filter library written in JAVA
https://github.com/berndporr/iirj
bandpass bandpass-filter bandstop bandstop-filter filter filter-plugin filters highpass highpass-filter iir lowpass-filter signal-processing
Last synced: 9 months ago
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An efficient IIR filter library written in JAVA
- Host: GitHub
- URL: https://github.com/berndporr/iirj
- Owner: berndporr
- License: apache-2.0
- Created: 2016-10-07T22:07:59.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2023-11-07T23:29:23.000Z (over 2 years ago)
- Last Synced: 2025-08-23T06:05:34.053Z (9 months ago)
- Topics: bandpass, bandpass-filter, bandstop, bandstop-filter, filter, filter-plugin, filters, highpass, highpass-filter, iir, lowpass-filter, signal-processing
- Language: Java
- Homepage:
- Size: 2.37 MB
- Stars: 144
- Watchers: 7
- Forks: 37
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
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README
# iirj
An IIR filter library written in JAVA.
Highpass, lowpass, bandpass and bandstop as
Butterworth, Bessel and Chebyshev Type I/II.
You can also calculate the filter coefficients with Python's
scipy and then create your custom IIR filter.
See the `python-design` subdirectory.
It's based on the IIR1 library [https://github.com/berndporr/iir1]
which in turn is based on Vinnie Falco's DSPFilters [https://github.com/vinniefalco/DSPFilters].
## Usage
`import uk.me.berndporr.iirj.*;`
### Constructor
`Butterworth butterworth = new Butterworth();`
### Initialisation
1. Bandstop
`butterworth.bandStop(order,Samplingfreq,Center freq,Width in frequ);`
2. Bandpass
`butterworth.bandPass(order,Samplingfreq,Center freq,Width in frequ);`
3. Lowpass
`butterworth.lowPass(order,Samplingfreq,Cutoff frequ);`
4. Highpass
`butterworth.highPass(order,Samplingfreq,Cutoff frequ);`
### Filtering
Sample by sample for realtime processing:
```
v = butterworth.filter(v)
```
## Coding examples
See the `*Test.java` files for complete examples
for all filter types. Run them with `mvn test`. These test programs
write the different impulse responses of the filters to text files.
## Installation
## Local install
- Clone this repository
- Run `mvn install` to add it to your local maven respository
## Maven central
At [](https://central.sonatype.com/artifact/uk.me.berndporr/iirj)
click on the iirj version number and then choose the appropriate installation option, for
example for Android studio.
## Android Studio
```
dependencies {
implementation group: 'uk.me.berndporr', name:'iirj', version: '1.7'
}
```
Android studio will automatically notify you if a new IIR library is available.
## Documentation
* Online: https://berndporr.github.io/iirj/
* `mvn javadoc:javadoc` generates the JavaDocs
* `mvn site` generates the web pages containing the documentation
under `target/site` describing all commands in detail.
## Testing
`mvn test` creates impulse responses in the subdirectories
for the different filters: `target/surefire-reports`.
To see the impulse and frequency responses run:
```
python3 ./plot_impulse_fresponse.py
```
where is is butterworth, bessel, chebyshevI or chebyshevII.
The script DetectorTest uses a bandpass filter to detect the
heartbeats of an ECG recording faking a matched filter which could
be also seen as a 1st approximation of a wavelet. The heartrate is
stored in hr.txt.
Have fun
/Bernd Porr
[http://www.berndporr.me.uk]