One of the key component in many GnuRadio projects is the quadrature frequency demodulator.
This functionality allows to calculate the real analog output of a frequency modulated signal from
the IQ-signal, which is mainly captured using HF hardware (e.g. dvb-t dongle, USRP, etc.) by a
carrier frequency (band pass domain) and transform it to the base band domain. The most known
implementations of the FM-demodulator are based on trigonometric functions. These functions
require a high computation effort. Some implementation of “tuned” trigonometric function, which
were downsized for FM-demodulation reduce the computation effort a little.
A new proposal of a so called arithmetic FM-Demodulator allows to avoid completely the usage of
any trigonometric function and speed up the computation process in many times.
In the presentation I will introduce mathematical background for the arithmetic FM-Demodulator,
show the differences and limitations to the current implementation in GnuRadio Version.
Further Philipp will present our result, we had achieved in our lab.
