Re: [Discuss-gnuradio] usrp2_rx_cfile.py issue

[Marcus D. Leech]

Actually, I am not using any sinusoidal function in this measurement. So, zero values are not valid I think. I am mostly using the noise signal so I thought there must be a value.
Here is a sample of what I got.

Any idea would be highly appreciated.

0.0001220703	-9.1552734375e-05
0.0001831055	-6.103515625e-05
9.1552734375e-05	0
0.0001220703	-0.0001220703
0.0001220703	-0.0001220703
6.103515625e-05	-3.0517578125e-05
0	-6.103515625e-05
0.0002441406	-6.103515625e-05
0	-6.103515625e-05
0.0002746582	0

How is it that you can be a masters student in electrical engineering, and *not* know that noise signals are simply the super-position
  of a large series of sinusoidal (or near-sinusoidal) functions?  Once again, the ADCs in an SDR receiver are sampling a complex voltage.
  That voltage may occupy any values between {-adc_resolution, +adc_resolution}.   In UHD, the ADC values are scaled (normalized)
   into the range {-1.0, +1.0} to make things within the flow-graph somewhat more general, and allow a certain amount of hardware
  independance.

In general, the samples of a noise source will be equally distributed about 0, and in fact you can confirm this by calculating the
  running-average of all your samples--they will tend to converge to 0 (in practice, there will be a small amount of DC offset which
  will cause this convergence to be not exactly at zero).

But all this should be in course textbooks, etc.  The folks here are generally kind, and patient, but they can't hope to teach people entire
  courses in electrical engineering, RF design, linear and non-linear circuit theory, and digital signal processing.  Although, those who
  *do*, generally charge money for it, in one way or another.

-- 
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org