On 31/03/2025 12:17, zhou via USRP-users wrote:
Hi Marcus,
Thanks for your quick response. I still have some doubt. In X410 spec,
there is clear information on max input rf power: +14dBm for f<3GHz,
+17dBm for f>3GHz
https://www.ni.com/docs/en-US/bundle/ettus-usrp-x410-specs/page/specs.html#GUID-50099182-F4E2-42EC-BBBD-7E336B07FFBE__GUID-B1D08221-A553-4A47-805A-896B34C98C07
If the max input signal power is -15dBm, the difference between X310
and X410 is too big.
Any further inputs will be appreciated.
They are completely different designs, with completely different
components. The X410 uses Xilinx RFSoCs that have
integrated RF chains inside the chips.
Now, having said THAT, the UBX-160 has either an MGA62563 LNA chip or
PMA3-83LN LNA chip "up front", depending on
the selected frequency range. Both of these chips can tolerate
considerably higher input powers. However, that doesn't
mean that components that are *downstream* from those LNAs are going
to be happy seeing those high input powers
*amplified* by the font-end LNA. So, for the most part,
Ettus/NI/Emerson recommend no more than -15dBm as
a safe, conservative, value. In the intended application space,
where they are intended to be directly antenna-connected,
a signal of -15dBm is "blow the doors off" loud.
On Monday 31 March 2025 at 16:59:11 BST, Marcus D. Leech
<patchvonbr...@gmail.com> wrote:
On 31/03/2025 11:51, zhou via USRP-users wrote:
Hi,
What is the max input signal power to RF ports in X310? There is a
spec in the below link:
https://www.ettus.com/wp-content/uploads/2024/01/X300_X310_Spec_Sheet_2024-01-23.pdf
<https://www.ettus.com/wp-content/uploads/2024/01/X300_X310_Spec_Sheet_2024-01-23.pdf>
There are max output powers, but not input power.
I am using UBX-160 daughterboard.
In X300/X310 Getting Started Guides - Ettus Knowledge Base
<https://kb.ettus.com/X300/X310_Getting_Started_Guides>, it says that
X300/X310 Getting Started Guides - Ettus Knowledge Base
<https://kb.ettus.com/X300/X310_Getting_Started_Guides>
"Never apply more than -15 dBm of power into any RF input."
ChatGpt says that "*UBX 40*: *+10 dBm* (10 mW)"
What is the max input signal power?
Thanks for any comments,
Zhou
-15dBm is somewhat conservative, but if that's what the manufacturer
recommends, I'd go with that, rather than a
hallucination produced by ChatGPT.
The receivers on USRPs are generally designed to be connected to an
antenna, and as such have sensitive, lower-noise
front-ends. Such front-ends generally don't tolerate higher input
powers without damage--and +10dBm *IS* high
input power for a radio receiver.
One may have gotten used to the relatively-insensitive inputs of
laboratory spectrum analyzers, which often have
inputs that can tolerate considerably-higher power levels, but are
insensitive at levels expected from direct
connection to an antenna. But USRPs are designed for antenna
connection. If you want to use them as
a laboratory spectrum analyser, you'll need to use attenuators.
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