[USRP-users] The receiver ADC goes into saturation

Dan CaJacob dan.cajacob at gmail.com
Sat Oct 25 14:25:36 EDT 2014


Everything The Marci said.

Specifically,

1. Reduce your TX amplitude to a maximum of 0.2, which should guarantee
linearity across many modulation types.
2. Reduce your TX gain to 0.  (You could even go a bit negative on some
daughtercards, I do sometimes)
3. Reduce your RX gain to 0.

If you have test equipment, you can now check the OTA (over the air) power
of the TXsignal nearby with an antenna.

I assume that you are using an antenna for both the TX and RX sides and
that the units are a decent distance apart to avoid damaging the front end
of the RX with too much power.

If your RX side is not working, incrementally increase the RX gain until it
does.  If you reach the maximum RX gain and it still doesn't work, only
then try increasing your TX gain.

Very Respectfully,

Dan CaJacob

On Sat, Oct 25, 2014 at 10:35 AM, Marcus D. Leech via USRP-users <
usrp-users at lists.ettus.com> wrote:

>  On 10/25/2014 08:28 AM, w xd via USRP-users wrote:
>
>  Hi all:
>        Environment:USRP N210,14bit ADC
>        According the formula:DR(dynamic range):6.02*14=84.28dB.
>        And now two USRP N210 close to each other,while one is used for transmitting and the other is used for receiving.The amplitude of the signal which to be send is 1.The gain in the transmitter I set 31.5dB.And the gain in the receiver I set also 31.5dB.The 31.5dB*2=63<DR(dynamic range).Why the receiver goes in saturation so easily?The signal saturates the ADC and gets clipped.Can someone explain it to me?
>        Thank you.
> Best regards,
> xd
>
>
>
> _______________________________________________
> USRP-users mailing listUSRP-users at lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>  To use a simple physical world analogy, you're *screaming loudly* into
> your friends ear, and wondering why they have gone temporarily deaf...
>
> Reduce your TX power and/or RX gain.
>
>
>
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>
>
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