Th. A. Prosch, DL8PT
Computer simulation of cascaded BiQuads
- GNU Radio Companion flow graph -

The flow graph file  "iq_biquad_konf3_qex1.grc" is read by the GNU Radio 
GNU Radio Companion which generates the file "Biphase_Hilbert_Network.py". 
The Python-skript simulates a digital bi-phase allpass filter network using
GNU Radio.
Sliders are available in order to change amplitude, frequency, and noise of the
test signal. The processed signal is displayed by GNU Radios's FFT-analyzer, and
is made audible by means of a stereo soundcard.

The coefficients of the IIR allpass filters (BiQuads) correspond to set III,
given in table 1 of the article "A minimalist approximation of the Hilbert 
transform". 

The preset address of the audio sink is hw:1.
 
I use LINUX, and I have installed version 3.2.2 of GNU Radio Companion.
An audio stick is plugged into the USB port of my notebook (Celeron,
2.2 GHz, 1GB memory). All works fine.
In case of trouble, check the hardware address of the audio sink. Possibly, it 
should be changed from hw:1 to hw:X, depending on the configuration of your 
platform.

Have fun when experimenting ...

vy 73 de DL8PT
