[prev in list] [next in list] [prev in thread] [next in thread]
List: gnuradio-discuss
Subject: Re: Questions on the GNU WiFi GUI with the USRP B210 box
From: "Marcus D. Leech" <patchvonbraun () gmail ! com>
Date: 2020-06-27 21:20:28
Message-ID: 5EF7B81C.3010505 () gmail ! com
[Download RAW message or body]
On 06/27/2020 04:55 PM, Silvio Cardero wrote:
> Thanks
> That goes with what I thought
> It seems to coincide with the ADC
> From my gain calculation and reading the transceiver specs the ADC
> should be a 1vp/p device hence 4 dBm FS + 3dB more for I&Q.
> Yet the GNU and Matlab views show the Received word seems to be 10 dBm
> FS or 1 v p/p
>
Gnu Radio doesn't give you numbers calibrated against powers or voltages
seen at the antenna, only some approximation of dBFS in the
digital domain. If you want that calibrated in "real world, as seen
at the antenna" units, you'll need to undertake a calibration exercise
over the multi-dimension parameter space of:
o Gain setting
o Frequency
o Analog bandwidth setting
o Sample rate
o Probably master clock rate
o Whether you're using TX/RX or RX2 port for RX
Since Gnu Radio (and, by inference MatLab) do not *KNOW* anything about
the analog behavior of the transceivers it's connected to, you
cannot come to any conclusions about what the instantaneous samples
*mean* in terms of real-world analog voltages other than that
they're mostly linearly related, and that for a given situation, a
larger sample magnitude means a larger output from the DAC (or, respectively
from the ADC).
[Attachment #3 (text/html)]
<html>
<head>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<div class="moz-cite-prefix">On 06/27/2020 04:55 PM, Silvio Cardero
wrote:<br>
</div>
<blockquote
cite="mid:76BA791D-7C9D-4BDA-A4C1-9ADBA1AF29F0@ed2corp.com"
type="cite">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Thanks
<div>That goes with what I thought </div>
<div>It seems to coincide with the ADC</div>
<div> From my gain calculation and reading the transceiver specs
the ADC should be a 1vp/p device hence 4 dBm FS + 3dB more for
I&Q. </div>
<div>Yet the GNU and Matlab views show the Received word seems to
be 10 dBm FS or 1 v p/p<br>
<br>
</div>
</blockquote>
Gnu Radio doesn't give you numbers calibrated against powers or
voltages seen at the antenna, only some approximation of dBFS in the<br>
digital domain. If you want that calibrated in "real world, as
seen at the antenna" units, you'll need to undertake a calibration
exercise<br>
over the multi-dimension parameter space of:<br>
<br>
o Gain setting<br>
o Frequency<br>
o Analog bandwidth setting<br>
o Sample rate<br>
o Probably master clock rate<br>
o Whether you're using TX/RX or RX2 port for RX<br>
<br>
Since Gnu Radio (and, by inference MatLab) do not *KNOW* anything
about the analog behavior of the transceivers it's connected to, you<br>
cannot come to any conclusions about what the instantaneous
samples *mean* in terms of real-world analog voltages other than
that<br>
they're mostly linearly related, and that for a given situation, a
larger sample magnitude means a larger output from the DAC (or,
respectively<br>
from the ADC).<br>
<br>
<br>
<br>
<br>
</body>
</html>
[prev in list] [next in list] [prev in thread] [next in thread]
Configure |
About |
News |
Add a list |
Sponsored by KoreLogic