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Topic: Why does a scope's update rate matter?
Total Replies: 6 Reply To This Topic

Why does a scope's update rate matter?
digitalJunk on 2/5/2010 10:20:00 PM

re:Why does a scope's update rate matter? 
Update rate is significant because it can impact your debugging methodology. If you know the glitch exists, it's easy to isolate it with a pulse-width trigger. However, it's the glitch that isn't suspected that causes the biggest problems. When you get a new circuit board, you usually "browse" from pin to pin. An oscilloscope with a fast update rate increases chances of finding the glitch during casual inspection—increasing your confidence in the board. If your not confident in the scope's display capability, then you will have to rely on its triggering system to search for each potential problem on each pin.
Crankshaft on 2/6/2010 11:43:00 AM

re:Why does a scope's update rate matter? 
A fast update rate is also useful in manufacturing test. Many of my tests require multiple acquisitions on the same test point to increase our measurement confidence. Large samples lead to better characterization of margins. Mask tests are an excellent example. A slow update rate forces a trade-off between lower test throughput and lower measurement confidence.
smsson on 2/6/2010 2:18:00 PM

re:Why does a scope's update rate matter? 
Update rate is a dynamic characteristic. It is relevant to repetitive acquisitions, not "single-shot" measurements. Update rate is constrained by the "dead time" between acquisitions and is blind to any events that occur during the dead time. It can vary with the scope's timebase settings, modes of operation, and its architecture such as the Agilent or Tektronix brand.
LITESONER on 2/7/2010 8:11:00 AM

re:Why does a scope's update rate matter? 
I prefer the Agilent brand particularly the Infinivision series but Tektronix is really known for good scopes. I have the DSO7104A and it fast. Take a look at it's datasheet which has a nice synopsis of why the update rate is important. You have to see this scope in person though. the DSO7104A blows away the TEK DPO4104A in my opinion
Crankshaft on 2/7/2010 10:52:00 AM

re:Why does a scope's update rate matter? 
It is really the interplay between update rate, sample rate and memory depth that determines the effectiveness of an oscilloscope and how confident you will be in its measurements that really matters. I prefer the Tektronix brand as I have been using it since my days in the Army. The TEK DPO7104A is the leader in all the banner specifications and should be the industry standard.
LITESONER on 2/10/2010 4:28:00 PM

re:Why does a scope's update rate matter? 
Thanks everyone. I will research and compare the Agilent DSO7104A and the Tek DPO7104A to see which one better fits my needs, though I really only need a 500MHz Scope at this time. Cool forum though!
digitalJunk on 2/10/2010 9:02:00 PM


Total Replies: 6 Reply To This Topic

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