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#### bigd43606

##### New Member
I am working on a project that involves a fiber optic distance sensor that produces an analog signal 0 to 5 volts. The object that sensor is measuring is vibrating at about 24kHz. I would like to measure the peak to peak amplitude of this 0 to 5 volt sensor which should look like a sin wave. The sensor manufacturer told us a Oscilloscope is the easiest way to get this measurement. We really don't do much with sensors and probably won’t use this for anything else. I like the Idea of a USB Oscilloscope so I can take screen shots and such. I also like the portability, as I could put it in my laptop bag and go to different sights. Would this be the way to go? I don’t mind spending $700 -$800 on this but am looking for recommendations on what to buy. Obviously I am looking for a good value, but I would prefer something that won’t fall apart and is pretty durable.
Don

#### vne147

##### Member
There are tons of cheap USB oscilloscopes on ebay but I think the old saying "You get what you pay for" is very true in this case. I have bought 2 USB scopes off ebay. The first of which was around $100. I fried that one. Never figured out exactly what I did to fry it but it no worky any more. The second scope I bought was around$80 and it still works but the included software was absolute garbage. One of the biggest limitations with these cheap USB scopes I've noticed is the sample rate. The first scope I bought was advertised at 200kHz but that was total, not per channel. So, if I was taking 4 measurements then the max sample rate I'd see would be 50 kHz. I'd pay close attention to the sample frequency when choosing a scope. If you're signal is 24kHz and your scope is 500 kHz for example, then you'd see about 20 data points per period. It'll be up to you to decide if that resolution suits your needs. Also, there are bench top scopes that can output to a computer so you do have other options than a USB scope for taking screen shots. And, there are hand held portable scopes too. $700 -$800 is a good budget. You should be able to find something that works for you.

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##### Well-Known Member
I agree with everything vne147 points out. Also as to the 0 to 5 volts, is that the output for a full span of distance? I ask because if your sine is going to be very tiny you need to look at a few more things. For example if the distance sensor measures 0 to 1" and outputs that as 0 to 5 volts and the vibration only amounts to a few thousandths of an inch you will be looking at a very tiny signal.

Ron

#### crutschow

##### Well-Known Member
Picoscope for one, has been around awhile, and seems to have a good selection of PC oscilloscopes.

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