Hello,

For more details, please find attached the received signal in the time domain. Clearly after the end of the packet, the signal takes a certain time to come back to "the ambient noise". If I zoom, I notice there is still some noise 40ms after the packet. It can disturb the reception of the following packet if its power is less than this additional noise.


What do you suggest to cancel it ? I'm using the USRP sink/source blocks from gnuradio for the transmission/reception parts.

Best,

Raphaël


On Thu, 08 Feb 2018 21:48:10 +0100, NAVES Raphael via USRP-users wrote:
Hello Dan,

Thanks for your answer. I'm using for transmitting the traditional
USRP sink block provided by Gnuradio Companion. Each packet coming to
this block is tagged with its length at the first sample. For the
receiving part, I'm using the USRP source block. Both are used with
basic parameters.

Do you think I should modify/use different parameters for these blocks ?

Raphaël

On Thu, 8 Feb 2018 11:54:07 -0500, Dan Veeneman wrote:
Hello Rafael,

Are you sure the transmitter has stopped radiating immediately after the
end of a packet?  The power amplifier on the transmitter may take a
small amount of time to go from powered up to powered down, although 40
milliseconds may be excessive.

Do you have a writeup and/or code for your burst transmission system
(transmitter and receiver), that perhaps others may be able to duplicate
the issue?


Regards,
Dan


On 2/8/2018 11:33 AM, NAVES Raphael via USRP-users wrote:
Hello everyone,

I implemented a burst transmission between two USRP N210. The
transmission and the packet receiving works well, however I'm facing the
following problem. From the reception side, I notice that after the
packet receiving, the sampling signal does not come back to the ambient noise immediatly. It takes few milliseconds (about 40 ms) to come back to "0". It's like if there is still a signal transmitted after the real packet transmission. It may be a problem when you want to receive many
consecutive packets with few space between them

 I suppose that it comes from an hardware problem when the signal is put on the baseband ? Does that deal with the LO leakage ? What can we do to
avoid this additional signal ?

Thanks,


Raphaël

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