Marcus,
Thanks for very nice explanation:
so I see the code of this block with the help of your reply, and
understand that how It is computing power for given N samples.
i.e power= (sum of X**2[n])/N where n goes from 0 to N.
And the code contains “noutput_items ” in place of N.
Then what value of N is used here. and how can we change that from
python code?
~Dilip
Sent from Windows Mail
From: Marcus L.
Sent: Thursday, August 29, 2013 8:44 PM
To: [email protected]
Cc: [email protected]
For a complex signal, the instantaneous power level is proportional to
(I2 + Q2), which you then average.
This is precisely what probe_avg_mag_sqrd does.
And, you shouldn’t refer to it as an “energy level”, since you’re
measuring power, not energy. Those are different (but related) concepts
in physics.
Now reducing even further, remember that the ADC is sampling a voltage
level. The power flowing through a circuit is proportional to the
square of the voltage.
The samples that are coming into the flow-graph are proportional to
the voltage seen by the ADC, so in order to calculate the power, you
have to square them.
Review Ohms law to see that this is true.
on Aug 29, 2013, dilip thapa [email protected] wrote:
Hi,
I want to do energy detection of received signal, And after searching I
was advised to use probe block to do the sense.
(gr.probe_avg_mag_sqrd_f).
Can anyone explain how this works. How level() method gives the energy
level. I need mathematic behind this function. Is this calculates based
on FFT or what?
Please help
and please add my email on reply.([email protected])
dilip