Re: [Discuss-gnuradio] Reg:Tags_demo.cc example

[Josh Blum]

On 03/12/2013 02:36 PM, Sean Nowlan wrote:
> On 03/12/2013 02:14 PM, Josh Blum wrote:
>>
>> 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.
> 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

> 
>> -josh
>>
>>> In the frac seconds i am getting 0.xxxxxx(only 6 digits after
>>> point-micro
>>> seconds)
>>>
>>> Thanks
>>>
>>>
>>>
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