Gstreamer Quadrature Library
libgstiq is a library with
plugins for use in software defined radios.
Download
Download version 0.2:libgstiq-0.2.tar.gz
Previous versions:
libgstiq-0.1.tar.gz
1200 Baud BPSK-RC test data:
Oscar-16 pass on November 11 2006 (FLAC format)
Very bad Oscar-16 pass on June 15 2005 (WAV format)
Dependencies
You need to have the fftw library installed. You can download it at http://www.fftw.org. Make sure you have atleast the float version installed.
Datatypes
libgstiq uses several new datatypes (besides the common audio and video types):| Media type | Description |
|---|---|
| audio/x-complex-float | This is the main type of libgstiq. It consists of complex float samples. (Two 32 bit float samples representing the two components of a quadrature signal) |
| audio/x-polar-float | This is a polar representation of the complex type. It consists of two float samples, the first is the absolute value of the sample, the second its angle in radians. |
| audio/x-fft-float | This is a frequency domain representation. It consists of blocks of a fixed length with complex float values. The new 'length' property determines the length of the fft conversion. |
| application/x-raw-float | Used for demodulated bitstreams. Each bit is represented using a float value. |
| application/x-tnc-kiss | Packetized AX.25 data stream in KISS format. |
The following software defined radio related modules are available:
| Name | Description | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| afc | Searches for the 'center' in audio/x-fft-float blocks. The center frequency can be read as the 'afc' property. The property 'mirror' can be used to prevent scanning of the negative frequencies when a mirrored (real instead of complex) signal is used. | ||||||||||||||
| bpskrcdem | Demodulates a BPSK-RC (Binairy Phase Shift Keying, Raised Cosine) signal into separate bits. | ||||||||||||||
| bpskrcmod | Modulates a BPSK-RC (Binairy Phase Shift Keying, Raised Cosine) signal from separate bits. | ||||||||||||||
| cmplxfft | Performs an FFT conversion on a audio/x-complex-float stream. The FFT length can be set as a property of the resulting audio/x-fft-float stream. | ||||||||||||||
| firblock | A simple FIR rectangular filter. | ||||||||||||||
| iqamdem | Demodulates AM signals. The 'depth' property can be used to set the standard modulation depth. | ||||||||||||||
| iqcmplx |
Converts between a stereo audio/x-raw-float signal and the audio/x-complex-float signal. Basicly it just renames data and doesn't change it. The following formats are interchangeable:
|
||||||||||||||
| iqfmdem | Demodulates FM signals. The 'deviation' property can be used to set the standard deviation. | ||||||||||||||
| iqfshift | Shifts a complex quadrature signal in frequency. The shift can be set with the 'shift' property. | ||||||||||||||
| iqpolar | Converts from the audio/x-complex-float vector format to the audio/x-polar-float polar format. | ||||||||||||||
| kissnrzi | AX.25 to NRZI encoder with KISS input. | ||||||||||||||
| manchestermod | Manchester modulator. | ||||||||||||||
| nrzikiss | NRZI to AX.25 decoder with KISS output. | ||||||||||||||
| vectorscope |
Generates a visual representation of complex data. (Also usable as an XY scope for normal data)
|
||||||||||||||
| waterfall |
Generates a visual waterfall from fft data.
|
||||||||||||||
Example programs: