OpenIGTLink/Timestamp - Revision history

Csoma at 21:58, 11 February 2008

2008-02-11T21:58:57Z

Csoma at 19:38, 10 January 2008

2008-01-10T19:38:44Z

Csoma at 19:37, 10 January 2008

2008-01-10T19:37:23Z

Csoma at 19:24, 10 January 2008

2008-01-10T19:24:36Z

Csoma at 18:02, 10 January 2008

2008-01-10T18:02:44Z

Csoma at 07:20, 10 January 2008

2008-01-10T07:20:02Z

Csoma: New page: << OpenIGTLink NTP4 Timestamp is defined by [http://www.faqs.org/rfcs/rfc2030.html RFC 2030] and [http://www.faqs.org/rfcs/rfc1305.html RFC 1305]. (See "3. NTP Ti...

2008-01-10T07:02:44Z

New page: << OpenIGTLink NTP4 Timestamp is defined by [http://www.faqs.org/rfcs/rfc2030.html RFC 2030] and [http://www.faqs.org/rfcs/rfc1305.html RFC 1305]. (See "3. NTP Ti...

New page

[[OpenIGTLink | << OpenIGTLink]]

NTP4 Timestamp is defined by [http://www.faqs.org/rfcs/rfc2030.html RFC 2030] and [http://www.faqs.org/rfcs/rfc1305.html RFC 1305]. (See "3. NTP Timestamp Format")

'''Big Endian format:''' NTP data are specified as integer or fixed-point
quantities, with bits numbered in big-endian fashion from 0 starting
at the left, or high-order, position.

'''Seconds and fraction of seconds:''' NTP timestamps are represented as a 64-bit unsigned
fixed-point number, in seconds relative to 0h on 1 January 1900. The
integer part is in the first 32 bits and the fraction part in the
last 32 bits. In the fraction part, the non-significant low order can
be set to 0.

'''Convention:''' Note that, since some time in 1968 (second 2,147,483,648) the most
significant bit (bit 0 of the integer part) has been set and that the
64-bit field will overflow some time in 2036 (second 4,294,967,296).
There will exist a 232-picosecond interval, henceforth ignored, every
136 years when the 64-bit field will be 0, which by convention is
interpreted as an invalid or unavailable timestamp.

If bit 0 is set, the UTC time is in the range 1968-2036 and UTC time
is reckoned from 0h 0m 0s UTC on 1 January 1900. If bit 0 is not
set, the time is in the range 2036-2104 and UTC time is calculated
from 6h 28m 16s UTC on 7 February 2036. Note that when calculating
the correspondence, 2000 is a leap year and leap seconds are not
included in the reckoning.

'''Precision:''' 200 picoseconds

'''Wrap around:''' in year 2104

← Older revision		Revision as of 21:58, 11 February 2008
Line 1:		Line 1:
−	[[OpenIGTLink \| << OpenIGTLink]] [[OpenIGTLink/Protocol \| ~~<<~~ Protocol]]	+	[[OpenIGTLink \| << OpenIGTLink]] \| [[OpenIGTLink/Protocol \| Protocol]]

@@ Line 13: / Line 13: @@
 == Obtaining timestamp ==
-* '''itk::RealTimeClock'''
+* [http://www.itk.org/Doxygen34/html/classitk_1_1RealTimeClock.html itk::RealTimeClock]
 * '''Linux''' / '''Mac''': [http://www.hmug.org/man/3/ftime.php ftime()]
 * '''Windows''': [http://msdn2.microsoft.com/en-us/library/z54t9z5f(VS.71).aspx ftime()] - 10 ms resolution

@@ Line 13: / Line 13: @@
 == Obtaining timestamp ==
 * '''Linux''' / '''Mac''': [http://www.hmug.org/man/3/ftime.php ftime()]
 * '''Windows''': [http://msdn2.microsoft.com/en-us/library/z54t9z5f(VS.71).aspx ftime()] - 10 ms resolution

← Older revision		Revision as of 19:24, 10 January 2008
Line 1:		Line 1:
−	[[OpenIGTLink \| << OpenIGTLink]]	+	[[OpenIGTLink \| << OpenIGTLink]] [[OpenIGTLink/Protocol \| << Protocol]]

@@ Line 2: / Line 2: @@
-NTP4 Timestamp is defined by [http://www.faqs.org/rfcs/rfc2030.html RFC 2030] and [http://www.faqs.org/rfcs/rfc1305.html RFC 1305]. (See "3. NTP Timestamp Format")
+'''Big Endian format:''' bits numbered in big-endian fashion from 0 starting at the left, or high-order, position.
-'''Big Endian format:''' NTP data are specified as integer or fixed-point
+'''Seconds and fraction of seconds:''' timestamps are represented as a 64-bit unsigned
-quantities, with bits numbered in big-endian fashion from 0 starting
+fixed-point number, in seconds relative to 00:00:00 January 1, 1970, UTC. The
-at the left, or high-order, position.
+integer part is in the first 32 bits (Unix-style timestamp) and the fraction part in the
 last 32 bits. In the fraction part, the non-significant low order can
 be set to 0.
-'''Convention:''' Note that, since some time in 1968 (second 2,147,483,648) the most
+'''Wrap around:''' The first 32-bit field will overflow some time in 2106 (second 4,294,967,296)
 == Obtaining timestamp ==
-Intel IA32 instruction [http://www.intel.com/design/pentium4/manuals/245471.htm RDTSC]
+== Time synchronization ==
-* '''Windows:''' Use [http://msdn2.microsoft.com/en-us/library/ms644904.aspx QueryPerformanceCounter()] or [http://msdn2.microsoft.com/en-us/library/ms713418(VS.85).aspx timeGetTime()] (10ms)
+Two solutions:
-== Calibrating the counters ==
+== Resources ==
-# Install NTP or compute timestamp differences
+* NTP4 Timestamp: [http://www.faqs.org/rfcs/rfc2030.html RFC 2030] and [http://www.faqs.org/rfcs/rfc1305.html RFC 1305]. (See "3. NTP Timestamp Format")
-# Calibrate timestamp (counter) - real time difference
+* [http://www.lochan.org/2005/keith-cl/useful/win32time.html Obtaining Accurate Timestamps under Windows XP]

← Older revision		Revision as of 07:20, 10 January 2008
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	'''Wrap around:''' in year 2104		'''Wrap around:''' in year 2104
		+
		+	== Obtaining timestamp ==
		+
		+	Intel IA32 instruction [http://www.intel.com/design/pentium4/manuals/245471.htm RDTSC]
		+	* '''Windows:''' Use [http://msdn2.microsoft.com/en-us/library/ms644904.aspx QueryPerformanceCounter()] or [http://msdn2.microsoft.com/en-us/library/ms713418(VS.85).aspx timeGetTime()] (10ms)
		+
		+	== Calibrating the counters ==
		+	# Install NTP or compute timestamp differences
		+	# Calibrate timestamp (counter) - real time difference