On 04/26/2010 01:41 PM, Josh Blum wrote:
In band signaling is a misnomer. But yes, the UHD supports time
stamped samples down to the precision of the clock. The time spec uses
a 32 bit integer for seconds and a double for fractional seconds (in
nanoseconds). The reason for using nanoseconds was to make the time
spec independent of the usrp device clock rate, since we will want to
support other clock rates than just usrp2-100Mhz.
The double has about 52 bits of mantissa, only 30 of which are needed
for the integer part of the nanoseconds. So I dont think there is room
for ambiguity as to which clock tick a time spec will refer to (for a
clock rate in 10s of Mhz).
-Josh
My main "looking forward to's":
o n-bit OTW format, to facilitate higher bandwidth: n=4,8,16
o a generic method for setting/getting auxillary
TTL/LVCMOS/LVTTL/whatever control bits
if the daughtercard has 'em, without necessarily giving up data
bits.
My radio astronomy work could benefit greatly from both of these, as
well as time-stamped sampling.
Actually, I do have a question about time-stamping. Are individual
samples timestamped, or just
blocks of samples?