Author Topic: EEVblog #323 - Rigol Scratch'n'Sniff  (Read 20926 times)

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Online mikeselectricstuff

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #50 on: July 31, 2012, 12:07:32 am »
Wow, that's the noise at _ten megahertz_?  Eeeewwwww.  (How's that for a sober engineering evaluation?)

Thanks for posting this.

It looks like they used the internal clock of their micro as the timebase, or maybe one of those little clock oscillators that has a synth inside.  It would take serious talent to make a plain crystal oscillator that bad.

Nice that it cleaned up with an external reference, but going to 1.5 GHz from 10 MHz lifts the reference noise by 43 dB, so we still can't tell how good it would eventually get.

But those noise sidebands.  Wow.  Just wow.

Cheers

Phil Hobbs
It uses an ADF4360 synth, driven by what looks like a standard osc module. The frequency was surprisingly accurate - ISTR less than 0.5ppm off my rubidium standard
Youtube channel:Taking wierd stuff apart. Very apart.
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Offline JackOfVA

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #51 on: July 31, 2012, 12:23:58 am »
It uses an ADF4360 synth, driven by what looks like a standard osc module. The frequency was surprisingly accurate - ISTR less than 0.5ppm off my rubidium standard


Mine was also quite good for accuracy and stability, compared against GPS standard. Plot below shows 4 days or so worth of stability as measured against an HP3816A GPS frequency standard. You can see the day/night temperature change in my basement lab. Not sure what caused the abrupt shift on the right hand side of the plot - GPS may have had a lock interruption.

 

Offline northlondonsage

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #52 on: August 10, 2012, 05:01:06 pm »
Is it ok to admit that I am realy jealous of Dave getting this stuff free in the mail...


There, I feel better for that....

 

Offline KTP

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #53 on: August 10, 2012, 05:22:31 pm »
Is it ok to admit that I am realy jealous of Dave getting this stuff free in the mail...


There, I feel better for that....

don't be jealous...he is doing it as a full time job now.

If you put the same effort he probably does into making these video reviews into a regular engineering job, you also could have these wonderful toys.  The only difference would be you have to send Agilent or Rigol these little pieces of paper you obtained from the job before they send you the toys.  The papers normally have pictures of famous people on them.

I do wonder if Australia makes Dave deduct the value of these from his income taxes...actually I have no idea how Australia does taxes...maybe they have so much gold they don't even bother taxing people.   ;D
 

Offline tnt

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #54 on: August 10, 2012, 05:46:02 pm »
I have an engineering job and I'm nowhere close to getting a 140k$ scope.
 

Offline pickle9000

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #55 on: August 10, 2012, 06:00:43 pm »
The expensive gear is only on loan I'm sure.

 

Offline KTP

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #56 on: August 10, 2012, 06:02:54 pm »
I have an engineering job and I'm nowhere close to getting a 140k$ scope.

He doesn't get to keep the 140K scope, so it is the same thing as you getting to use stuff at work.

I worked a long time ago as a student intern for a government entity and was building and testing semi-rigid cable on a $100,000 HP network analyzer....and this was in the 1980s...that would be like $250K today.
 

Offline olsenn

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #57 on: August 10, 2012, 06:31:14 pm »
What's with the comments about the noise floor being bad on the Rigol spectrum analyzer? Of course I have nothing to compare it too, but I never notice the noise floor on mine to be bad at all... especially with the built in preamplifier.
 

Offline Rufus

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #58 on: August 10, 2012, 09:21:46 pm »
What's with the comments about the noise floor being bad on the Rigol spectrum analyzer? Of course I have nothing to compare it too, but I never notice the noise floor on mine to be bad at all... especially with the built in preamplifier.

There are no comments about noise floor. The comments are about phase noise.
 

Offline mortos360

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #59 on: August 13, 2012, 09:08:26 am »
When is the review video coming?
 

Online EEVblog

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #60 on: August 13, 2012, 09:13:33 am »
The expensive gear is only on loan I'm sure.

The $140K 90000 scope and PFANG are only on loan.
You can get loans of them too at work, just ask Agilent. Most other companies or local suppliers have loaners too.

Dave.
 

Offline tnt

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #61 on: August 13, 2012, 09:35:16 am »
Test setup is to set the 4102 to 10.050 MHz, 0 dBm sine and feed it to a MiniCircuits connectorized double balanced mixer. The other RF input port to the mixer connects to the 10 MHz reference output of an HP 3816A GPS disciplined oscillator. Mixer output is centered at 50 KHz and connects to an HP3562A dynamic signal analyzer with a 50 ohm coaxial through termination at the 3562A input.

I think that setup is a bit unfair to the internal timebase.

Since you use the same 10 MHz source for the mixer as the one you feed to the Rigol, any noise on the source would just not appear at all (since it's the same noise on both side of the mixer).

But at least it shows the ADF itself doesn't add too much noise.
 


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