Re: Digital O'scopes: Sampling Rate vs. Sample Storage Space

Rich Webb wrote:
On Fri, 15 Aug 2008 14:28:23 -0700 (PDT), sodaant@xxxxxxxxx wrote:

What is the relative importance of sampling rate versus sample memory
in a digital oscilloscope?

I'm looking at two candidates: one has a sampling rate of 2GS/sec, but
only 2.5K of sample memory, while the other samples at only 400MS/sec,
but has 1M of sample memory.

For debugging microcontroller systems with typical peripherals (I2C,
SPI, ADC, LCD), which is more important, sampling rate or sample
memory size?

For your stated purpose, I'd say that a better candidate would be a
logic analyzer. Whereas PC-based, USB-interfaced o'scopes tend to be a
bit underpowered, similar logic analyzers are often cost effective and a
good fit for a home/hobby lab. Hit Google for "usb logic analyzer" for a
long list of candidates. My personal favorite (which gets a lot of use
developing professional products as well) is the Intronix logic analyzer
from http://www.pctestinstruments.com/. This one includes "interpreters"
for RS-232, I2C, SPI, and CAN protocols; very handy.


A logic analyzer cannot easily detect marginal line conditions such as overshoots, reflections, marginal levels, bus contentions. I'd go with a scope.


For o'scopes, I'd recommend that you also look at the digital scopes
from Instek, which are pretty well thought of around here (I don't have
one but I am looking for an excuse...). One source is over at
http://www.tequipment.net/InstekGDS-2202.html


Yep, got a GDS-2204, happy with it. Bought it via Newark because they had the best price:

http://www.newark.com/jsp/search/browse.jsp?N=500003+1001455&Ntk=gensearch_001&Ntt=Instek&Ntx=

Yesterday I had to work with one of those TI lunchbox-size scopes at a client. Oh man, what a step back after being used to the Instek. Especially when I hit the 2.5K brick wall at the end of its memory bank where the Instek got 25K.

--
Regards, Joerg

http://www.analogconsultants.com/

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Use another domain or send PM.
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Relevant Pages

  • Re: Digital Oscopes: Sampling Rate vs. Sample Storage Space
    ... only 2.5K of sample memory, while the other samples at only 400MS/sec, ... SPI, ADC, LCD), which is more important, sampling rate or sample ... Hit Google for "usb logic analyzer" for a ... long list of candidates. ...
    (sci.electronics.design)
  • Digital Oscopes: Sampling Rate vs. Sample Storage Space
    ... What is the relative importance of sampling rate versus sample memory ... in a digital oscilloscope? ... I'm looking at two candidates: one has a sampling rate of 2GS/sec, ...
    (sci.electronics.design)
  • Re: Digital Oscopes: Sampling Rate vs. Sample Storage Space
    ... in a digital oscilloscope? ... only 2.5K of sample memory, while the other samples at only 400MS/sec, ... SPI, ADC, LCD), which is more important, sampling rate or sample ... Hit Google for "usb logic analyzer" for a ...
    (sci.electronics.design)
  • Re: Digital Oscopes: Sampling Rate vs. Sample Storage Space
    ... in a digital oscilloscope? ... only 2.5K of sample memory, while the other samples at only 400MS/sec, ... Hit Google for "usb logic analyzer" for a ... Logic analysers are handy tools, but NOT as good a scope. ...
    (sci.electronics.design)
  • Re: Digital Oscopes: Sampling Rate vs. Sample Storage Space
    ... in a digital oscilloscope? ... only 2.5K of sample memory, while the other samples at only 400MS/sec, ... SPI, ADC, LCD), which is more important, sampling rate or sample ... One could of course argue that a logic analyser might be more useful ...
    (sci.electronics.design)
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