Accurate time stamping?
Accurate time stamping?
(OP)
I need to design a data acquisition system with time stamping capability and the accuracy should be at least uS level. But the RTC chips I found can only count to seconds.
Any good suggestion?
Thanks.
Any good suggestion?
Thanks.





RE: Accurate time stamping?
<nbucska@pcperipherals.com>
RE: Accurate time stamping?
RE: Accurate time stamping?
or relative to some timing signal ? 300 m ( about 1000 Ft )
difference in location will cause 1uS difference !!
Solar or sidereal time ?
Is this a school project ?
<nbucska@pcperipherals.com>
RE: Accurate time stamping?
It is not school project, it is for my work.
RE: Accurate time stamping?
TTFN
RE: Accurate time stamping?
http://www.datum.com/res_library/busLevelTimecode.PDF
etc. for more info
RE: Accurate time stamping?
http://www.microsoft.com/hwdev/platform/proc/mm-timer.asp
etc. for hardware info
RE: Accurate time stamping?
We are trying to build a high-speed wireless sensor which can transmit real-time sensor data to receiver at 100KSPS (12-bits per samples). We also want it to have a time stamping capability with precision at least to 1 millisecond.
Right now I am thinking use the ADuc812 from Analog Device for the DAQ part. And use a SPI-compatible RTC connected to ADuc812 for time-stamping. However, it seems to me all RTC IC can only counts to second, not millisecond. Which is my biggest headche right now.
Since we want to have a small sensor, then GPS-based time stamping maybe not suitable.
RE: Accurate time stamping?
This assumes the hardware/software you use for the time stamping is flexible enough to accomodate 5 registers being read serially.
RE: Accurate time stamping?
If you're doing a standalone RTC and you don't want to use a GPS receiver, then you have to live with the consequences and simply take a stabilized crystal time base and free-run the clock.
Your RTC chip is only going to be good for about 1 second a month at best, which means it'll have an error of 30 ms a day, minimum.
I don't understand why you are having this difficulty with the RTC. You must have a controller. Every controller has some sort of timer capability, particularly single-chip embedded processors. These timers usually have resolutions better than 10 uS.
TTFN
RE: Accurate time stamping?
http://www.analog.com/Analog_Root/productPage/productHome/0,,ADuC812,00.html
for features of ADuC812:
8-Channel, 5µs, Self-Calibrating, 12-Bit ADC
Two 12-Bit Rail-to-Rail Voltage-Output DACs
Industry Standard 8052 Microcontroller
///8052 Microcontroller have a timer\\\
8K-Byte In-Circuit Re-Programmable Flash Program Memory
640-Byte Read/Write Accessible Non-Volatile Flash Data Memory
Temperature Monitor
Voltage Reference, Serial Interface Ports, Watchdog Timer,
///Here is a timer\\\
Power Supply Monitor, etc
Embedded Download/Debug & Emulation Features
Furthermore, visit
http://www.8052.com/tut8052.phtml
for:
256 bytes of Internal RAM (compared to 128 in the standard 8051).
A third 16-bit timer, capable of a number of new operation modes and 16-bit reloads.
///Here is a timer\\\
Additional SFRs to support the functionality offered by the third timer.
RE: Accurate time stamping?
Good luck.
RE: Accurate time stamping?
RE: Accurate time stamping?
The index of refraction being high in fiber is what keeps the light in the fiber.
RE: Accurate time stamping?
Please!! mS and ms are not the same thing!
mS is milliSiemens, a unit of conductivity (Siemens formerly called mhos).
ms is milliseconds, a unit of time.