[Discuss-gnuradio] usrp_spectrum_sense.py

[Carlo D'Elia]

Hi all,
I'm new in this world... but I'm trying to understand the program usrp_spectrum_sense.py.

I want to know how many samples my usrp capture at a given time period.
It should theoretically capture in n seconds----------> USRP_RATE x n seconds.

For example

in 10 seconds => 4 MS/s x 10s = 40M Samples
in 60 seconds => 4 MS/s x 60s = 240M Samples
in 120 seconds => 4 MS/s x 120s = 480M Samples
I use the default values.
But in my case when I lunch the program with an appropriate counter in the usrp_source_base.cc file , I check the number of samples captured and in nine different experiments they are:


1) experiment

in 10 seconds => 7.18193 e7 Samples 

2) experiment

in 60 seconds => 3.60591 e8 Samples

3) experiment

in 120 seconds => 1.25783 e9 Samples

4) experiment

in 10 seconds => 8.82063 e7 Samples

5) experiment

in 60 seconds => 3.4864 e8 Samples

6) experiment

in 120seconds => 1.22311 e9 Samples

7) experiment

in 10 seconds => 5.97432 e7 Samples

8) experiment

in 60 seconds => 4.15018 e8 Samples

9) experiment

in 120 seconds => 7.2589 e8 Samples


How is possible that these values don't correspond to the theoretical values?? And why is the real USRP_RATE different?