Rudimentary PC USB oscilloscope?

On Thu, 03 Sep 2015 14:19:09 -0700, John Larkin Gave us:

No shit. I was simply telling him about his USB endeavors.

I bought 3 Tektronix scopes in the last week, and even a nice analog unit last month. As well as two network analyzers, and two signal generators.

Bought a cheap chinese sig gen last month. It is nowhere near as useful as the HP. The USB scope is pretty much a cursory baseline thing which barely does what it claims to do.

It is a Virtin's Technology Multi-instrument.

The claim that standalone units are cheaper for the same functionality sounds like BS to me. I did scope them out yesterday... Lots of comments on the PC USB scopes by people who have actually bought them suggest otherwise.

But I'm not interested in entertaining trolls on this contentious issue. Have fun.

I picked up a low end Hantek MSO a few months ago. I don't know how well it can work because I never got the software to install properly. The seller gave me my money back because the shipper lost all tracking info. Easier than arguing over the perceived value of a device I can't get to work.

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Rick

I would expect a USB scope to be cheaper if nothing else, because there is no display and control hardware. But it doesn't seem to pan out that way.

I want a USB scope so I can put it in my computer bag and capture screens on the laptop. I want to have it all portable in one bag with the PC.

But then it looks like I may need a new PC. The only thing I can access on the Internet is newsgroup access. I wonder if any laptops come with a built in oscope yet?

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Rick

I'd rather have the low-end 100 MHz Rigol. The Rigol samples at 1 GHz, but the Virtin samples at 100 MHz in 2-channel mode. The Rigol is cheaper, although it doesn't include the ARB.

It clearly can't be a dual-channel 80 MHz scope, sampling at 100 MHz. It's marginal in single-channel mode.

Connecting a laptop, and installing all that software and stuff, sounds like a nuisance to me, too.

The Virtin sort of thing might be useful in automated test sets.

True enough about input Z. I measured several USB sound cards (and one built-in) over a price range from $15 to $90 and found input impedances on Line In from 5K to 49K. and on Mic In (usually best avoided) from 1.6K to 3M. (See "USB Sound Card Performance Tests" at )

Much of the time this isn't a big deal, or can easily be dealt with.

But, yeah, a "real" (hardware) scope is unquestionably better if you just want to grab a quick measurement of a totally unknown signal.

On the other hand, the sound card shines when you want to automate a test series, or generate exotic test signals, or get trigger sync on an exotic test signal (like an FM modulator), or calibrate for transducer response, or view color spectrograms, or use synchronous waveform averaging to view signals below the noise floor, and so on.

I keep both on my test bench; each has its place.

Best regards,

Bob Masta DAQARTA v8.00 Data AcQuisition And Real-Time Analysis

Scope, Spectrum, Spectrogram, Sound Level Meter Frequency Counter, Pitch Track, Pitch-to-MIDI FREE 8-channel Signal Generator, DaqMusiq generator Science with your sound card!