On 06/25/2018 07:20 AM, Andreas Bauer via USRP-users wrote: > Hello, > > > we are currently working with a USRP X310 with a Twin RX daughter board. > We are interested on more information about the CHDR protocol. > > > The documentation on https://files.ettus.com/manual/page_rtp.html seems > to be not enough. The concrete questions are as follows: > > > - What does the /Fractional Time /exactly stand for? -> What does it > say? e.g. What does it mean if the "/Has fractional time > stamp"-/bit/ /is set and/ /all bits of the "/Fractional Time" /are set > to zero? > > - What's the time-format of the /Fractional Time /and what is the > data-format of the/Fractional Time/?/ -> microseconds, milliseconds, > seconds? integer, float, double?/
The time is in number of ticks. "Fractional" is a bit misleading. Ticks get incremented with the sample clock, so, every 10ns it will increment by 1. (10ns because you have a 100 MHz sample clock in TwinRX). > /- /Can we get or find a more precise dokumentation about the/Radio > Transport Protocol /than on https://files.ettus.com/manual/page_rtp.html ? > > - Is it right that the whole CHDR header and the data trailer is > transmitted over udp with the endianness of /Big-endian/ or does the > header and data trailer differ from each other? -> Which endianness does > the header and the data trailer have? It's all network-endianness (so, big). Here's all the packing and unpacking code: https://github.com/EttusResearch/uhddev/blob/master/host/lib/transport/chdr.cpp -- M > > > Thank you for your effort. > > > regards > > Andreas > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > _______________________________________________ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
