As different modulation technics in digital communication emerges, there is a need for more efficient modulation technics, example for such modulation technic is Quadrature Amplitude Modulation (QAM).
This blog is for anyone wanting to learn about QAM and GNU Radio. It is written to depict and describe aspects of QAM in a way that is hopefully easy to grasp.
GNU Radio companion is beautiful and superior software to illustrate different modulation technics, now let’s see how to implement QAM in GNU Radio companion.
Ability of equipment to distinguish small differences in phase limits the bit rate. This can be improved by combining ASK and PSK. This combined modulation technique is known Quadrature Amplitude Modulation (QAM). Advantages of QAM is that it is possible to obtain higher data rate using QAM.
Quadrature amplitude modulation (QAM) is both an analog and a digital modulation scheme. It conveys two analog message signals, or two digital bit streams, by changing (modulating) the amplitudes of two carrier waves, using the amplitude-shift keying (ASK) digital modulation scheme or amplitude modulation (AM) analog modulation scheme.
To know more about implementation of QAM in GNU Radio companion, please click on the link for the application note below,
http://www.tenettech.com/product/7013/quadrature-amplitude-modulation-with-gnu-radio
