[USRP-users] The receiver ADC goes into saturation

Marcus Müller marcus.mueller at ettus.com
Sat Oct 25 15:47:41 EDT 2014


Hi Dan,

On October 25, 2014 8:25:36 PM CEST, Dan CaJacob via USRP-users <usrp-users at lists.ettus.com> wrote:
>Everything The Marci said.
The Marci with a capital M and a capital T. I suddenly feel meaningful :)
We're going to need a logo and a motto.

Cheers,
Marcus The Less Experienced

>
>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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