# Reg:Tags_demo.cc example

Hi,

1. What is get_full_seconds and get_frac_seconds printing?

2.Can we get upto precision of nano seconds using the above methods and
please tell me how to do it.
In the frac seconds i am getting 0.xxxxxx(only 6 digits after
point-micro
seconds)

Thanks

On 03/11/2013 09:52 PM, john jade wrote:

Hi,

1. What is get_full_seconds and get_frac_seconds printing?

Its probably the receive timestamp, its the time stamp from this object:

http://files.ettus.com/uhd_docs/doxygen/html/classuhd_1_1time__spec__t.html

2.Can we get upto precision of nano seconds using the above methods and
please tell me how to do it.

The fractional seconds are stored as double precision floating point.
This gives the fractional seconds enough precision to unambiguously
specify a clock-tick/sample-count up to rates of several petahertz.

-josh

On 03/12/2013 02:14 PM, Josh B. wrote:

2.Can we get upto precision of nano seconds using the above methods and
please tell me how to do it.
The fractional seconds are stored as double precision floating point.
This gives the fractional seconds enough precision to unambiguously
specify a clock-tick/sample-count up to rates of several petahertz.
Although time can be represented with petahertz+ resolution, doesn’t
the hardware clock constrain the realizable resolution? For example on
a USRP with a 100 MHz FPGA clock, would actual transmit precision be
limited to 10 ns?

On 03/12/2013 02:36 PM, Sean Nowlan wrote:

2.Can we get upto precision of nano seconds using the above methods and
please tell me how to do it.
The fractional seconds are stored as double precision floating point.
This gives the fractional seconds enough precision to unambiguously
specify a clock-tick/sample-count up to rates of several petahertz.
Although time can be represented with petahertz+ resolution, doesn’t
the hardware clock constrain the realizable resolution? For example on
a USRP with a 100 MHz FPGA clock, would actual transmit precision be
limited to 10 ns?

The resolution as to which clock tick an event would happen at is only
as fine as the clock you are using. -josh