Author Topic: EEVblog #323 - Rigol Scratch'n'Sniff  (Read 24760 times)

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Offline EEVblogTopic starter

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EEVblog #323 - Rigol Scratch'n'Sniff
« on: July 26, 2012, 01:01:10 pm »


Dave.
 

Offline nitro2k01

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #1 on: July 26, 2012, 01:20:07 pm »
The audio output seemed fairly noisy, and and a bit distorted. At the higher frequencies, it sounded a bit too distorted to be a sine. When you turned the frequency down, it sounded like the modulating wave was in itself modulated by a lower frequency wave. I wonder what's going on there.
And I was hoping to hear the voice waveform...
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Offline mikeselectricstuff

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #2 on: July 26, 2012, 01:27:59 pm »
I struggled to hear what that voice is saying, depending on sample rate it could be "Rigol" or "Help Me"..
Teardown here in case anyone missed it:

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Offline firewalker

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #3 on: July 26, 2012, 01:45:01 pm »
I struggled to hear what that voice is saying, depending on sample rate it could be "Rigol" or "Help Me"..

"Help me! Mike plays with my chips!"

 ;D ;D ;D

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Offline Architect_1077

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #4 on: July 26, 2012, 03:29:31 pm »
Dave, something I'm wondering about:

Do you have to pay taxes and/or postage on things that companies send you for review?
 

Offline M. András

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #5 on: July 26, 2012, 05:29:09 pm »
i seriously doubt when they quote 100usd for each unit, as for a demo unit its already used so they cant complain about that, they wont send you a 4k series rigol? i would love to see the comparsion to the x3k series agilent
 

Offline tnt

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #6 on: July 26, 2012, 05:42:09 pm »
@Dave: When reviewing them, could you use the spectrum analyzer to check the phase noise of the arb sig gen ? I'm curious to know how good it is.
 

Offline Chet T16

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #7 on: July 26, 2012, 06:07:00 pm »
The DG1022 has the pulsing power button too and that's quite old now. I kind of like it but I just know if I had another bit of rigol gear the unsynced pulsing would blow my OCD fuse
Chet
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Offline TheWelly888

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #8 on: July 26, 2012, 06:20:34 pm »
Somehow I find the pulsing flashing standby light rather creepy - I suppose I have been watching too many sci-fi horror flicks!  ;D

Seriously I was very impressed with the build quality of the signal generator that Mike took apart.
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Offline chrome

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #9 on: July 26, 2012, 06:28:12 pm »
I find the flashing light not to be a problem at all (don't know about power consumption though) but the light is so dim, it's in my room and I don't even notice it and I face the device when sleeping.
 

Offline Zad

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #10 on: July 26, 2012, 06:35:58 pm »
If a unit is sent out on loan for review, rather than being given to the recipient, $100 is not an unreasonable nominal fee. There should be no tax to pay on it.

The modulated output sounded much more like a square wave. Very harsh at the lower frequencies with lots of overtones. Maybe it was fooling the AGC and clipping the input gain.

One thing that still amazes me when people un-box stuff, they try to lift a comparatively heavy item out of a cardboard box. This means you have to struggle clamp the box between your feet or get someone to hold it, wobble the item around and risk dropping it or falling over. Far easier to fold the flaps back, rotate the package onto the side, then onto what was the top. Lift the cardboard box off. Done. Obviously don't be a twonk and do this on a floor strewn with gravel and an unprotected item (very rare nowadays).
« Last Edit: July 26, 2012, 06:50:08 pm by Zad »
 

Offline Alexei.Polkhanov

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #11 on: July 26, 2012, 09:04:33 pm »
This is it, I am going to start my rant here :-)

Second review for Rigol function gen I am watching in last week. what I am hearing is "It is heavy", "Nice solid design", "have quality appearance". Mikeelectricsfuff did first review - same thing. "it is heavy". WTF guys! Let's not be like house wives reviewing dish washing machines. 

Anyone will ever bother looking at data sheet? This thing has jitter 500ps (Agilent is <40ps), amplitude accuracy ... I am not an expert in function generators at all, but first time I tried one - rise time and jitter were so bad it was useless for me and I am not doing anything complicated.

Some good practical advice on how to choose function gen for project would have helped enormously.
 

Offline KTP

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #12 on: July 26, 2012, 09:16:19 pm »

Anyone will ever bother looking at data sheet? This thing has jitter 500ps (Agilent is <40ps), amplitude accuracy ... I am not an expert in function generators at all, but first time I tried one - rise time and jitter were so bad it was useless for me and I am not doing anything complicated.


But but, it is heavy!    ;D
 

Offline firewalker

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #13 on: July 26, 2012, 09:48:36 pm »
I believe that the "heavy" part has to do with the physical construction. The first impression will be good if you pick up something solid, stiff and heavy. I don't recall Mike saying that it is heavy thus it is good as a function generator.

Alexander.
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Offline dda

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #14 on: July 26, 2012, 10:05:31 pm »
What is the difference between a 'real' counter and not one?
 

Offline EEVblogTopic starter

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #15 on: July 26, 2012, 10:30:11 pm »
Do you have to pay taxes and/or postage on things that companies send you for review?

No. In this case they were invoice marked as demo units, with a value of $100. Customs limit in Oz is a generous $1000.

Dave.
 

Offline Zad

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #16 on: July 26, 2012, 11:09:18 pm »
This is it, I am going to start my rant here :-)

Second review for Rigol function gen I am watching in last week.

No you didn't. You watched 1 unboxing (Dave's) and 1 teardown (Mike's). Both explicitly said they weren't reviews.

I imagine the jitter clears up massively with an external clock source, which as we all know can be obtained very cheaply from Ebay.

Offline mikeselectricstuff

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #17 on: July 26, 2012, 11:13:18 pm »
What is the difference between a 'real' counter and not one?
On a scope, it can either have dedicated counter hardware (usually as part of the  FPGA) , or it can measure frequency from samples in the acquistion memory. The latter has limitations, in particular counter resolution is tied to sample rate, and the upper end is limited.
 
The Rigol DG has a hardware frequency counter, but it is IMO badly implemented as it uses gate times which are power-of-2 multiples of the 500MHz clock, instead of powers of ten, so if you measure 10.000 000 MHz you get a reading that flips between 2 odd-looking values (neither of which are 10.000 000 at faster gate times) due to non-decimal rounding issues. It also displays far more digits than can possibly be meaningful at the selected gate time.

 
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Offline Alexei.Polkhanov

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #18 on: July 27, 2012, 12:10:44 am »
I imagine the jitter clears up massively with an external clock source, which as we all know can be obtained very cheaply from Ebay.

Well yes, kind of. If we look at jitter closely - we have 3 kinds, absolute jitter, period jitter and cycle-to-cycle jitter. Plugging in rubidium clock source into 10MHz external clock input affects only cycle-to-cycle jitter. This kind of "fix" was first thing that came to my mind :-) It did not help, not significantly.
I noticed that there are different lines on datasheet for these things one expressed in ppm another in ps. It is not clear to me if picosecond value refers to period or absolute, but ppm shows value for cycle-to-cycle jitter.
 

Offline RRobot

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #19 on: July 27, 2012, 02:37:16 am »
This is it, I am going to start my rant here :-)

Second review for Rigol function gen I am watching in last week. what I am hearing is "It is heavy", "Nice solid design", "have quality appearance". Mikeelectricsfuff did first review - same thing. "it is heavy". WTF guys! Let's not be like house wives reviewing dish washing machines. 

Anyone will ever bother looking at data sheet? This thing has jitter 500ps (Agilent is <40ps), amplitude accuracy ... I am not an expert in function generators at all, but first time I tried one - rise time and jitter were so bad it was useless for me and I am not doing anything complicated.

Some good practical advice on how to choose function gen for project would have helped enormously.

In my opinion so long as Rigol documented the specs of their AWG accurately its up to you to study them before buying.  Yes the 33521A has <40 ps jitter, but is worse (and in a few things better) then the Rigol in other specs and it also costs more ($2000). Also rise time on the Agilent (8.4ns) seems comparable to the Rigol (8-12 ns depending on the model). If you want something with a much lower rise time your looking at a lot more money, something like the PFANG.


« Last Edit: July 27, 2012, 02:42:07 am by RRobot »
 

Offline EEVblogTopic starter

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #20 on: July 27, 2012, 02:40:48 am »
In my opinion so long as Rigol documented the specs of their AWG accurately its up to you to study them before buying.  Yes the 33521A has <40 ps jitter, but is worse (and better) then the Rigol in other specs and it also costs more ($2000). Also rise time on the Agilent (8.4ns) seems comparable to the Rigol (8-12 ns depending on the model). If you want something with a lower higher rise time your looking at a lot more money, something like the PFANG.

Yes, this is designed as a sub $1K class instrument. The high end model is more, but you aren't really paying for the extra design effort there.

Dave.
 

Offline free_electron

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #21 on: July 27, 2012, 03:30:07 am »
mailbag monday  : where dave opens his maul
teardown tuesdays : where dave rips stuff apart
whatever wednesdays : where dave does whatever
teaching thursdays : where dave explains stuff
frying fridays  : where dave blows up stuff
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Any comments, or points of view expressed, are my own and not endorsed , induced or compensated by my employer(s).
 

Offline KTP

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #22 on: July 27, 2012, 03:48:00 am »
frying fridays  : where dave blows up stuff

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Offline ivan747

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #23 on: July 27, 2012, 04:17:34 am »
The audio output seemed fairly noisy, and and a bit distorted. At the higher frequencies, it sounded a bit too distorted to be a sine. When you turned the frequency down, it sounded like the modulating wave was in itself modulated by a lower frequency wave. I wonder what's going on there.
And I was hoping to hear the voice waveform...

Maybe what you are hearing are the effects of audio compression.
 

Offline ivan747

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Re: EEVblog #323 - Rigol Scratch'n'Sniff
« Reply #24 on: July 27, 2012, 04:20:12 am »
What is the difference between a 'real' counter and not one?

This one is heavy.

 ;D
 


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