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Author Topic: What kind of oscilloscope should I buy?  (Read 2255 times)
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Here's my advice ...

I have a digital scope, and a logic analyzer. And what do I use every day? The logic analyzer. I use the scope maybe once a week.

http://www.saleae.com/logic/

For $149 you get a lot of useful features.

You can capture 10 billion samples! Try doing that with your scope! Unless you are prepared to spend tens of thousands of dollars.



It interprets serial, I2C, SPI, CAN, Manchester, and other stuff. So rather than counting 1s and 0s the actual data is displayed (as above).

The Arduino is a digital device, basically. Analyzing digital data is more important than analog. Of course analog is useful if you are trying to get to the depths of why a circuit is not working. But the logic analyzer is really, really, useful.

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fungus, I'm thinking about getting a DSO Quad, since it can be used as a logic analyzer (perfect for serial RX/TX and i2c).

I was working on an I2C driver for an ATtiny a few days ago. I would never have fixed it without my Quad to look at the lines.

I've also been looking at recommended firmwares.
You said your formware was the GCC APP firmware. I think the UI looks a bit complicated,

It's not massively intuitive, no, but it's way more useful than the original firmware.

so I found gabonator's little baby; https://github.com/gabonator/DS203

May I ask, What kind of apps are you using? do you have some recommended apps? have you tested the Quadpawn app?

I honestly haven't tried many of them.

Sorry about all these questions, but I'm just so curious about this little, open source scope! how much better will the bandwidth if I either remove (saw it in a guide) or relplace it?

The difference is like night and day. With the bad diode in place any digital signal above 1MHz comes out as a flat line (I could see signals on the analog inputs but not the digital inputs - it should be the other way around!) With removed/replaced diode everything was perfect.

I don't know the new bandwidth limit because Arduinos can only output signals up to 8MHz. I know it shows 8MHz perfectly.
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Here's my advice ...

I have a digital scope, and a logic analyzer. And what do I use every day? The logic analyzer. I use the scope maybe once a week.

There may be wisdom in this, too.

(if you already have an analog 'scope for the times when you need one...)
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Quote from: Nick Gammon on March 05, 2013, 07:29:26 AM
Here's my advice ...

I have a digital scope, and a logic analyser. And what do I use every day? The logic analyser. I use the scope maybe once a week.

About a month ago I also have this question.I tend to a logic analyser Saleae product. It really worth every cent spent on it. I also buy a  digital scope.It was my Christmas gift smiley-lol
I bought a Rigol DS1052E  |  50 MHz.
But I don use it very often.
I suggest follow Nick Gammon advice
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I currently own a Tektronix 2213 dual channel 50 MHz O'scope... and I am with lefty on "Prying..." Almost...
I want to be buried with mine. My next serious purchase will be the device that Nick Gammon uses.
I have Long been an admirer of Saelig, I remember them when they were 'New" too. No one stays in business as long as they have been without good reason and I aim to buy a piece of that reason.
I use my scope for things analog mostly... But with 2 input channels and an external sync 'input' I can display a lot of things.. 'digital display..' but it is still, analog.. Delayed sweep was the only advantage I had in a situation where I had to display both sides of an RS232 'conversation'.
The point is that the best idea is to use the best tool for the job and an analog scope is a fine addition to any persons "Tool-Box"for analog work. Most of the stuff I see here however could be done as well with an LED and a driver transistor (Logic Probe?). In my direct experience an O'scope has NO comparison to a Logic Analyzer... and the Logic Probe is best for looking at pulses... If you aren't fortunate enough to own an O'scope/Analyzer.. The reason is simple.. many pulses will get under sampled by poor refresh rates of cheap DMM's but the human eye responds well to 10 mS pulses. Few DMM's are capable and I wouldn't want to put my Fluke 179 to that test.
An O'scope was intended to look at one or two things at a time. Try to use a 4 channel scope on the inputs and outputs of a stereo amplifier sometime. The data on an average 5" screen is worthless except for things heard easier than seen, although displayed accurately... in a 25 mm wide window perhaps 10 cm long. Due to the display limitations the ear will pick up defects long before they are apparent on the O'scope.
I should Never try to write before 6 AM. {Edit RKJ}

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« Last Edit: March 06, 2013, 02:55:26 pm by Docedison » Logged

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I bought myself a Rigol DS1053E oscilloscope a couple of months ago. Very happy with it, I use it regularly. Sometimes just as an "advanced multimeter". I also have an Open Workbench Logic Sniffer. I bought it because I am playing with several I2C sensors and IC's. It's a very handy tool to debug code.
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That logic analyzer screen shot that Nick posted looks pretty great.  I don't have an LA, just a scope (Rigol DS1102E).

The scope is great for doing things that scopes do best... I.e., a multimeter with a time scale.  I use it extensively on analog projects, although being a digital scope, the resolution at the screen is not the greatest.  But I can quickly see when my op-amp circuit is throwing DC on the output.  It's also great for testing PSUs.  I can see how much ripple I'm getting through a filtered rectifier, and how much the load affects the output.

If you're doing digital i/f, the LA will tell you what's wrong with the data, and the scope will tell you when there are abnormalities in the signalling.  Both extremely useful, IMO.
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I must agree with Nick, devices like those are brilliant. I use a Digilent Analog Discovery, I got it for £100 posted here in the UK - 2 scope channels, 16 digital channels, 2 waveform generators fully software controllable, +&-5V power supply and multiple ground connections.

Brilliant little device

http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,842,1018&Prod=ANALOG-DISCOVERY
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