Which logic analyzer to choose

Discussion in 'General Electronics Chat' started by burricios69, Jan 17, 2015.

  1. burricios69

    Thread Starter New Member

    Dec 14, 2014
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    Hi guys,
    I'm thinking of getting some king of logic analyzer/usb oscilloscope. I'm quite a beginner on electronics, but I think I could really use one of these.

    I've seen the Openbench Logic Analyzer, which seems very nice and for a great price (just 50$+6$ for the probes). I still have a question though, I've seen it has a maximum sampling frequency of 200MHz. If i were to capture 4 channels, at 100MHz, would that mean 25MHz for each channel, which would only allow me to capture, for example, clock signals of up to 25Mhz per channel?
    The fact that the last version for this analyzer is from 2010 back me down a bit, would it be smart to buy a logic analyzer from almost 5 years ago?

    My other option was the Bus Pirate, but I've seen it has kind of a different utility, so I dont think it fits what I'm looking for.

    If you guys could give me your opinion about this two, or any other recomendations, I would really appreciate it.

    Thank you!
     
  2. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    I just browsed Openbench and did not see where it supported protocols. That is a VERY useful feature of logic analyzers IMHO. I have the Logic Cube. A bit more expensive than the Openbench but it is a mature product and supports a ton of protocols.
     
  3. burricios69

    Thread Starter New Member

    Dec 14, 2014
    18
    0
    It actually supports protocols. It uses Open Logic Sniffer (OLS), which support spi, i2c, uart, among others.

    Would you really recommend Logic Cube over Openbench?
    Thanks
     
  4. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    Well after that bit of knowledge, I might look at Open Bench myself. I have had Logic Cube for years and really like it though the support can be challenging as it is Chinese. They are really helpful and responsive just difficult to understand sometimes.

    How is the support for Open Bench?

    Is there an enclosure available?
     
  5. WBahn

    Moderator

    Mar 31, 2012
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    4,788
    It's hard to give any kind of an opinion when we have no idea what you are looking for.

    If you are sampling at 25MSa/s then you cannot capture a clock signal at 25MHz because you would be capturing the signal at the same point in the waveform each cycle and, hence, your captured trace would appear to be DC. This is called aliasing. The fastest content you can capture is half the sampling rate. In practice, you shouldn't push this too hard, so it is nice to limit your signals to about 1/10 or 1/5 of the sampling rate.

    As for getting something that is a few years old, my scope (which has a logic analyzer built into it) is nearly twenty years old and lots and lots of people use equipment that is from the 50s and 60s. Nothing wrong with old equipment -- what counts is whether it satisfies YOUR needs (not your wants, but your needs -- wants can be considered, but don't talk yourself into spending big bucks to get something that you want instead of something much cheaper that does everything you need).
     
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