Which USB scope is the best deal?

Jul 01, 2007 12 Replies

Hello Folks,



When looking at that market there is a myriad of options. Which one is the best from a price performance point of view? Does anyone have good experience with a particular model?



USB, 2-Channel, 500MS/sec or more would be nice. SW-FFT, decent doc capabilities, the usual. If it needs a separate supply that's fine.



I don't need it in the lab so much but more on the road. Noise hunting etc. I wish someone would also make a somewhat decent spectrum analyzer for USB but that market still looks totally untapped.



There comes a point in most people's lives where the lower back doesn't want to schlepp heavy lab gear or you run the chance of not being able to move the next day.


Regards, Joerg http://www.analogconsultants.com

About five years ago I used one of Pico Technology Ltd's slow PC-based scopes - 12-bits at up to 7kHz - which plugged into the parallel port. Farnell still stocks something like it - the ADC42 (order code

318-0827, 134 euro).

It worked fine, and the software that came with it was fair easy to use, and didn't crash.

Farnell now carries a bunch of their faster USB-based scopes, with sampling rates up to 200Msamples/sec. The A/D converters are strictly

8-bit parts. Prices run from 600 euro to 1200 euro depending on speed.

Farnell also stock two Picoscope Oscilloscope/Spectrum analysers offering a 12-bit A/D sampling at up to 50 or 100Msamples/sec, the ADC-212/50 and the ADC-212/100. They plug into the parallel port can cost 700 euro and 950 euro respectively.

They might be worth looking at.

Farnell don't stock the whole Picoscope range

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-- Bill Sloman, Nijmegen

But they don't meet the requirements. You can get a reasonable A2D converter (in price and power consumption) for 200 MSPS. But for

500MSPS (as requested by OP) or beyond, it's ridiculously expensive and hot (in power).

500MS/s knocks out all of the low and middle end USB scopes. At this level you kind of start not worrying about the cost, and make your decision based just on the performance you need.

Picoscope make a new one in this performance range but I have not used it:

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It's got a massive buffer which is excellent. Sample rate drops to

500MS/s with two channels though.

Dave.

Well, the Tek TDS2012B has a USB port, 1GS/s, 2 ports, SW FFT, very portable. Of course the computer is optional. :) Since it came out, the non-B models have come down in price.

You can thank me for the arrival of the B series, it happened right after I bought a TDS2014.

Ben Jackson AD7GD http://www.ben.com/

The "requirements" appear to be a wish list, rather than non- negotiable constraints, and I mentioned where the units I put forward fell short of the requirements.

Why do you think it is necessary to waste bandwidth by reposting this information?

The "ridiculousness" of the price depends on the application, which Joerg didn't spell out. There other aspects of A/D performance which can also be important in some applications, but since Joerg was asking about units that he could buy rather than devices that he could use to build his own, this isn't all that relevant to this thread.

-- Bill Sloman, Nijmegen

Because your suggestion is off-base, he asked for 500 MSPS USB and you suggested 100 MSPS parallel port.

Cost of the chip is definitely relevant to the devices available on the market. If it can be made with reasonable price, it will be available.

I've looked at PicoScopes, mostly because an engineer from a client bought one. He didn't run it through the paces yet because that the purchase was very recently.

Don't know if they are from England but the US prices seem highish, could as well get a Tek portable for that money. Or a Chinese knock-off ...

Regards, Joerg http://www.analogconsultants.com

Yeah, I've relaized that :-(

That's the one I was eyeing. A bit pricey for a USB scope but if it works good that may be ok. Anyone used it for tricky stuff a lot already?

Regards, Joerg http://www.analogconsultants.com

Thanks, have to check that out. As long as it isn't as as that TDS220.

Regards, Joerg http://www.analogconsultants.com

Grow up. Note that the Picoscope wb-sited that I posted includes two devices - the 5203 and the 5204 offering 1Gsample/sec and a USB interface. Both are expensive, and Farnell doesn't stock them (which may mean that Picoscope can't make them in volume, which might - in turn - have something to do with the yield on the A/D converters being used).

Dream on. USB-oscilloscopes aren't high volume products. They have to use chips that are predominantly made for other, larger, markets. These chips aren't always reliably available to low volume manufacturers - if the main market takes off the low volume manufacturers find themselves with six month delivery times. I can still remember buying up the last 36 of a particular single chip processor available from Dutch distributors for my ex-employer in the UK, when Volkswagen had bought up every one that Siemens was producing for the next six months ...

-- Bill Sloman, Nijmegen

Have you looked at the Cleverscope? See

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Their comparison chart at
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claims it's pretty good, but there may be some selective data presentation there. It's a bit down on sample rate, but has a lot of storage and good resolution. It's small and light, and the software is pretty nice.

I have only "played" with one at a demo, but have a customer who swears by it.

Barry

Thanks, Barry, but 100MS/sec isn't going to work for my usual projects.

Regards, Joerg http://www.analogconsultants.com

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