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Rigol digital storage oscilloscope


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#1 Robert

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Posted 21 July 2013 - 02:11 PM

Hi Router,

 

On another thread you mentioned that you have a Rigol and you said "for the most part I really like it".

 

I happen to be looking to buy a Rigol, specifically the DS1052E. I've got a search active on Ebay to let me know of listings for it.

 

I wonder if you might expand upon your comment and describe its shortcomings, apart from the obvious of only having 2 channels and a 50 KHz bandwidth (which, for my modest lab ambitions, are unlikely to be an issue).

 

 

 

Erratum: Yes, I meant 50 MHz, not KHz.


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#2 G4ΓΓ3ττ

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Posted 21 July 2013 - 04:42 PM

Robert the Rigol scope has *50Mhz* of bandwidth, also, you can boost that to more than 150Mhz with a firmware mod! I own one and have done the mod, super simple to do btw, and have tested the actual bandwidth with a Fluke RF signal generator and a Tektronix 284 ~70ps pulse generator.

 

The rise time of the scope after the mod was aroound 2.1 nanoseconds (with 32x averaging and "equivalent sample rate" on) which comes out to be 166Mhz of bandwidth. [LaTeX Error: One or more directories do not exist] [bandwidth in megacycles per second, from the 10-90 rise time in nanoseconds]

 

I'll post some picures of how to test bandwidth later.

 

A four channel scope of at least 500Mhz of bandwidth would be *ideal*, actually a scope with 1Ghz of bandwidth would be the best but obviously hard to get for a good price. Older Tektronix scopes are the way to go for higher scope bandwidth. If however, you want a *new* scope, the Rigol or some other Chinese scope is really your only option when money is tight.


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#3 Raui

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Posted 22 July 2013 - 02:39 AM

Robert,

I have the DS1102E DSO which is a 2CH 100MHz scope. This scope has been very handy for me. I'd like to see extended math functionality which I alluded to in my other post, like to be able to do numerical calculations on the data in realtime and have it displayed on the scope. For example you could have a 5Ohm resistor which you want to know the current so you'd have a script on your drive somewhere that reads CH1/5 and thus gives you the current. It's more for convenience than anything else. I could easily do the same thing by saving the data and doing in in a spreadsheet program.

 

One feature I absolutely love is the FFT which turns your oscilloscope into a spectrum analyser. Although one thing I have found that is a slight pain in the ass is that it only goes down to 2mV/div sensitivity which is pretty good really but sometimes I've wanted a more sensitive readout. What do you want for your money though.

 

One issue I know does exist with Rigols from my experience with them at uni is that sometimes they cannot read/write to USB devices bigger than 2 or 4GB. I know I've got an 8GB stick lying around here somewhere, I'll try find it and test it out and see how she goes and let you know.

 

Like Garrett said, you can flash the 50MHz models to the 1102E because all the internals are the same it's just the 50MHz model has a firmware restriction on it. I was discussing this with a tutor at uni earlier in the semester as he had the 50MHz model. He said he's pretty sure that all the components are the same but that the 100MHz models would be the ones with more preferable component characteristics in them. For example you might have two capacitors supposedly 5nF you measure one and it's 5.1nF and the other is 7nF so the 5.1nF capacitor would have your circuitry working more as you planned than the 7nF capacitor. Since the oscilloscope contains a truckload of components these little nuances add up. The tutor said that he hadn't had a problem yet though and he does a fair bit of HAM work so I'd trust him on that one.


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#4 G4ΓΓ3ττ

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Posted 22 July 2013 - 05:16 AM

Router,

 

From what I remember system bandwidth of these particular scopes actually has most to do with the TI DACs used in the scope. The Chinese engineers thought it would be best to overclock the DACs rather than buy ones that were binned to spec for their needs. Also they made a third 150Mhz "model" (for schools only?), which is the model I changed to in my scopes firmware--and it does indeed work! Tested it multiple ways to make sure. All bandwidth limitations for these particular scopes exist in firmware, NOT hardware. To get the extra bandwidth out of the scope, the firmware, upon checking the model of the unit upon boot up, controls some of the analog frontend filters (variactor diodes) and overclocks the DACs. So not all scopes will be stable when reflashed with the different model number. However, I haven't had a problem with that. I did however, have some dodgy rotary encoders, and sent my unit back to Rigol, and got a whole new scope in return. So customer service, at least in USA, is pretty top notch.


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