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Ask Slashdot: PC-Based Oscilloscopes On a Microbudget? 172

Posted by timothy
from the not-yet-part-of-every-smartphone dept.
New submitter fffdddooo (3692429) writes I know it's something that people used to ask every few years, but answers get old so quickly. I'm an electronics teacher, and I'm wondering if it's possible to find some oscilloscope (and why not spectrum analyser?) for recommending to my students, to be able to work at home. I'm thinking of something near $50-$70. Two or three years ago, I'm sure the answer was No, but nowadays? The same reader points out two options spotted on Amazon: one that's "very cheap but Khz" (it's also a kit that requires assembly), and another that aims to be capable of 20MHz, 2-channel operation. What's out there, he'd like to know, that's not junk?
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Ask Slashdot: PC-Based Oscilloscopes On a Microbudget?

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  • Salae logic (Score:3, Insightful)

    by Technician (215283) on Thursday June 12, 2014 @04:12PM (#47224825)

    When recommending test equipment, I tell them the same thing that I tell those needing a PC and ask for recommendations. I ask what are your requirements, and what are your wishlist.

    Start with the essentials. Do you need Microsoft Office, why? Do you need to keep in a budget? If so how much and why? Can you spend extra for extras? If you can get the extra from an alternate for less, would it meet your requirements?

    The PC scope. Define your requirements. Budget is item one listed. This severly limits your options. Is above audio REQUIRED? If not some simple audio interfaces can be used. On Linux there is an oscope program that works great with a sound card. Back to requirements, are you taking absolute voltage measurements? Do you require DC coupling? If so this is not an option that meets your requirements.

    If working in audio frequencies, there are some excellent free spectrum analizers for free in Linux and not sure what is the options in Windows or Mac. For Linear Frequency and Log amplitude the JAAA program in most linux repositories whorks great. For Log frequency and Log amplitude, the companion JAPA program works great. I use it to ring monitors for band/PA. Audacity does a great job creating waveforms. I use it to create frequency sweeps for sound setup with the JAPA program. The sweep generation is a little obscure. Under Generate tab, it is the Chirp function. Set start frequency, end frequency, start amplitude and end amplitude, liner or log sweep, and duration of the "Chirp" to generate your signal.

    For those with a good soundcard or external audio interface the generated sound is direct digital so any noise is not in the recording, but in the analog stream after the digital. Be sure to set the project frequency high, such as 96KHZ, in Audacity to prevent ailising in the upper frequencies. This is a better signal source than any CD recorded sweep due to the higher sample frequency than 44.1K of CD.

    To recap, due to budget, shop for what is free or low cost. Your interface to the outside world will be your expense. There are low cost or no cost software that can enable better capture hardware. The above while nice did not meet the stated budget requirement. Retails for $299. So is the wishlist able to justify the higher cost?

  • Re:Salae logic (Score:3, Insightful)

    by mean pun (717227) on Thursday June 12, 2014 @04:15PM (#47224843)

    Since the OP asked in parentheses for spectrum analyser suggestions, he seems to be interested in cheap measurement instruments in general. I don't think a logic analyser is too far off topic.

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