Anyone familar with the BitScope?

[jamont]

This is an inexpensive box that purports to turn your computer into a digital oscilloscope, for more info see http://www.bitscope.com

Is this a useful tool for audio? Does if replace a conventional oscilloscope? Can it serve as a spectrum analyzer? Does anyone own one? Thanks for any information.

 

[morsel]

Tangent owns one, but it is fairly limited. I seem to recall it is an 8 bit device. You would be better off with a real scope, an M-Audio sound card, RightMark Audio Analyzer, and whatever more advanced software you can afford.

 

[jamont]

After some poking around at the web site, I find that your memory serves you well, it does indeed take 8-bit samples.

That's too bad, I was looking at it as a possible replacement for my 25+ year old analog scope. It's not been triggering so well recently, clearly the day is coming...

Thanks, morsel.

 

[tangent]

Now hang on a minute there. It depends on what you want to do before you can judge whether 8 bits is sufficient. Even Tek DSOs worth thousands of dollars use 8 bit samples, because their screens are set up for 256 pixels of waveform display area vertically. 8 bits is all you need for looking at waveforms.

It's also nice to have a good sound card, but for different purposes, mainly for you need more than 48dB of dynamic range. Things like SNR measurements and spectrum analysis are much more useful when you have 16 or 24 bits per sample.

For that matter, an analog scope has its purpose, too. A CRO is better than either a sound card or a DSO for some things.

A DSO should probably be last on the shopping list for audio. It's very convenient to have a small box that you can keep near your computer for doing quick measurements, especially if you don't have to space to keep your big CRO on the workbench all the time. You could use the DSO for quick checks and then drag out the CRO when you need a better dynamic picture of the signal in action.

Now all that aside, there is one thing about the Bitscope that you need to know, if you decide you want one. While it's usable now, and it's been improving steadily for years now, the available software is still a bit rough. This is changing quickly now, as Bitscope Designs is in late beta now on a new DSO program for the Bitscope which blows every other Bitscope-compatible program out of the water. I've been using both the Windows and the Linux version for a few months now, and it's getting quite good lately.

EDIT: If you decide to get one, be sure and get the network option. The speed improvement is very dramatic. Actually there's supposed to be a USB adapter available soon, too, which will have the same speed advantage. (Both are limited by a 600 Kbit/s bottleneck.) The USB version might be tricky to make work on non-Windows systems, though. The network module uses UDP, so it'll work with any computer that has a TCP/IP network stack. It's also nice to know you could put the Bitscope as much as 100 yards away from the PC if you wanted to. USB has a much shorter max distance limit.

 

[jamont]

Well, more to think about. Thanks, tangent.

How does the Bitscope compare with your Tek TDS 320?

 

[tangent]

The TDS320 isn't mine, it was borrowed from work, which is one reason I got the Bitscope -- my boss wanted his scope back. But also, the Tek took up too much space on my small work bench.

I miss the Tek anyway. The Bitscope software doesn't yet have measurement capabilities built into it. I miss being able to ask the scope to tell me the frequency or the p-p voltage of the signal it's seeing instead of figuring it out myself by counting divisions. There's also a lot to be said in favor of real knobs vs. GUI buttons. Often getting the Bitscope set up to give a sane picture is harder than it was for the Tek. This is partly the usability aspects of knobs, but also because the Tek has a wider range in all respects -- bandwidth, input voltage range, etc. -- so you're less likely to get effects like truncated waveforms due to overdriving the voltage range of the input stage.

None of this means I regret buying the Bitscope. But if bench space and money were no object, I wouldn't mind having a Tek replacement for it. That's just wishful thinking, of course. I've considered getting a used Tek analog scope and storing it under the bench and dragging it out for the tough jobs. But then I realize that it would collect lots of dust, because I'd use the Bitscope first whenever I could. What I need most of all is more bench space, and that just isn't forthcoming.