> Another way of determining the the arrival time of a pulse with high > resolution is to use centroid timing techniques. The input pulse is > converted to a short pulse using a delay line timed monostable then > the resultant pulse is low pass filtered by a discrete component RLC > Gaussian low pass filter.
This sounds like fun. Thanks. > A sampling ADC continuously samples the low pass filter output at a > fixed clock speed. The centroid of the pulse can then be calculated > from the resultant sequence of ADC samples. Monostable output pulse > width ~ 2x ADC sample clock period. Low pass filter risetime ~ 2 ADC > sample clock periods. With a 10MHz sample clock a resolution of > 100picosec or better can be achieved with a 12 bit ADC. The idea seems simple, but I don't see how to write the code. Is there a good URL on that? Table lookup and average? (make the table from spice or such) > A delay line timed monostable is required for low output pulse jitter > and good output pulse width temperature stabilty. 2x 100 ns delay line seems like a pain. What's the (ballpark) tempco of coax? What's the ballbark tempco of a normal (whatever that means) delay chip? (Assume I use a chip designed for this rather than kludging gate delays.) Can I correct for the change in pulse width if I have more samples? How much accuracy do I give up by making the pulse wider so I can get more info on the width/height of the pulse in order to correct? -- The suespammers.org mail server is located in California. So are all my other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited commercial e-mail to my suespammers.org address or any of my other addresses. These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
