what is the meaning of IQ sampling rate

[smourad]

please I want to know what is the meaning of IQ sampling rate and how can in change it ? it depends in what? and what is its utility? 

thanks

[Rodéric_L]

Please read this page for IQ data: http://www.ni.com/tutorial/4805/en/ 

How to change the sampling rate might depend on the hardware you are using...