Re: [Discuss-gnuradio] tx_time tag accuraccy

[bob wole]

Can I have  a comment on it?

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Bob

On Thu, Jun 5, 2014 at 11:02 AM, bob wole <address@hidden> wrote:

Sorry for not stating the hardware earlier. I am using USRP N210, with RFX2400 and WBX boards.

 

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Bob

On Wed, Jun 4, 2014 at 11:07 PM, Marcus Leech <address@hidden> wrote:

I don't know the detailed answer, but any such answer will depend very much on which USRP hardware you're talking about.

 

One of the R&D people who deals with the FPGA codebase may be able to give a precise answer, given stated hardware.

 

 

 

on Jun 04, 2014, bob wole <address@hidden> wrote:

Marcus! Thanks for you comment.

 

I think that USRP transmit FIFO is at the start of the DSP chain in FPGA i.e it is prior to both of the interpolation filters? right?  I am not talking about when the burst will be over the air, I want to know when the first sample of the burst will leave the transmit FIFO if it has been tagged as tx_time=X.

 

 

 

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Bob

On Wed, Jun 4, 2014 at 10:51 PM, Marcus Leech <address@hidden> wrote:

It will depend some on the effective group delay of both the interpolation filters in the the FPGA and the analog group delay of the analog bits of whatever daughtercard you're using.

 

The only way to be sure is to measure...

 

 

on Jun 04, 2014, bob wole via USRP-users <address@hidden> wrote:

I am using stream tags for the transmission control. I want to know what is the accuracy/precision of the tx_time tag? E.g if I tag a burst A with tx_time=X, then the burst A will come out of the USRP transmit FIFO at X+delta, how large the value of delta could be? 

 

 

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Bob

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