Author Topic: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator  (Read 108761 times)

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Offline cybermaus

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #475 on: January 12, 2018, 12:41:53 am »
I also checked for phase shift again, using a constant 5v amplitude, and found that the two channels were only 1.4nS apart after going from 1MHz to 60MHz, although both had also shifted another 2nS along the time axis.  I haven't read your explanation of the 4nS discrepancy you found, Chris, but my readings indicate that it might just be a bit of "natural variation" (in a sample size of two).

Interesting. I wonder if that is something they fixed going from my 3.1 to your 3.2.
Because for me, it is very clear and certain: 4ns timeshift on the phase over the entire frequency range. Which I interpret as always exactly 1 tick too late on the 250MHz DAC clock
Something that probably is fixable, and maybe they did  :)

Though numerically, I wonder where your new 1.4ns value would then come from. Can you test this specifically with some frequencies which are whole divisions of the 250mHz clock. Like 50.00, 41.66, 35.71, 31.25, 27.77, 25.00 MHz
If it does not happen there, I may be able to come up with some technobabble on how aliasing could cause this.


Has anybody addressed or figured out the reason (or reasons) for the jitter (for example, about 4 ns jittering on the falling edge of the squarewave) in this unit? Has anybody suggested any solutions yet? I suppose, just changing the clock oscillator to an ultra-low jitter type wouldn't help here. Thanks to everybody's input!

Yes, I am pretty sure its its due to the 250MHz DAC clock. So each next sample is 4ns apart, and alas they cannot make a wave rise or fall in the middle of that.
So while the 4ns phase difference is avoidable, I suspect the the 4ns jitter is not. At least, not on a AWG generator.
(a PLL generator would of course be able to get a cleaner square wave)

 

Offline Mr. Scram

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #476 on: January 12, 2018, 01:21:54 am »
Hi, everyone,

Has anybody addressed or figured out the reason (or reasons) for the jitter (for example, about 4 ns jittering on the falling edge of the squarewave) in this unit? Has anybody suggested any solutions yet? I suppose, just changing the clock oscillator to an ultra-low jitter type wouldn't help here. Thanks to everybody's input!
Isn't that the classic square wave frequency not being divisible by the clock frequency jitter?
 

Offline Vytautas

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #477 on: January 12, 2018, 06:58:46 am »
Thanks, cybermaus, looks to be just it. Well, you get what you pay for.  :(
« Last Edit: January 12, 2018, 07:01:22 am by Vytautas »
 

Offline cybermaus

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #478 on: January 12, 2018, 07:56:21 am »
Not sure I agree to that.

There are some issues with this device, but the 4ns jitter? I strongly suspect that the 10x more expensive equivalent Rigol DG1062Z 60Mhz 2 channel AWG has the same issue.
So we are getting a more then we paid for.

In fact, all of the device is a good deal, with all quirks, even the leaky PSU, if you check price/performance to what said equivalent Rigol would cost.
Only the firmware-self-destruct is below par. So far below par I cannot advise the device till they have a warranty system.
 
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Online Marco

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #479 on: January 12, 2018, 08:05:38 am »
As I said, what we should be asking for is firmware we can use to fix our devices. It's the most realistic solution.

PS. I still say change the title of this thread to mention bricking to apply a little pressure, it's a top google result for this device, it can help ... or at least provide a tiny bit of retribution. With the single post from the OP it was clearly an advertising post any way, an advertising post for a device which fucked a fair few forum members.
« Last Edit: January 12, 2018, 08:12:05 am by Marco »
 

Offline rhb

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #480 on: January 12, 2018, 08:20:07 am »
I previously suggested a thread entitled "FeelTech FY-6600 Product Support Reviews" with all the empty promises from FeelTech and the sellers posted.

I plan to do this as soon as I have recovered from my bout of flu.
 

Offline cybermaus

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #481 on: January 12, 2018, 08:33:59 am »
I don't think we can change the thread title, can we? It was started by a Feeltech marketing shill.
I do not think Dave would change the title for us. Would set a nasty precedent.

It is the first google result though, a new thread would not easily take that over.

Just always make sure the last page has at least one clear statement "do not buy unless feeltech finally gives warranty" message.
 

Offline rhb

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #482 on: January 12, 2018, 09:46:55 am »
I just went through a maddening exercise trying to contact Paypal and eBay who clearly don't want to allow you to contact them except by checkbox forms.  It would appear that I shall have to write a paper letter to complain to eBay.

I ordered mine on 20 Nov and first contacted FeelTech on 8 December.  I feel fairly certain that the strategy at FeelTech is to stall the user until the Paypal and EBay protections expire.

In the meantime, I've modified my .sig.  I should like to suggest that others do similarly.  That will spread the word rather widely.
 

Offline bitseeker

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #483 on: January 12, 2018, 09:59:52 am »
rhb, yeah, it is buried a bit deeply. However, you can call them by navigating as follows:

1. Go to https://ocsnext.ebay.com/ocs/home
2. Click Contact us button
3. Select Buying
4. Select Returns
5. Select Returning an item
6. At the bottom of the page, click Call us or call me button
You don't acquire TEA. It acquires you.
 

Offline DaveR

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #484 on: January 12, 2018, 10:13:36 am »
Can you test this specifically with some frequencies which are whole divisions of the 250mHz clock. Like 50.00, 41.66, 35.71, 31.25, 27.77, 25.00 MHz

I did the measurements at the requested frequencies, a lot more carefully than the previous day's rough look, and took the average over four separate trials, after a 30 minute warm up period.  The Ch1 trace was centered exactly on the crosshairs at 25MHz, and the Ch2 lag time was measured at each frequency, the results being:

25.00MHZ   1.00nS
27.77MHz   1.00nS
31.25MHZ   1.10nS
35.71MHz   1.00nS
41.66MHz   1.10nS
50.00MHz   1.20nS

In fact, the relative phase shift was constant from at least 5Mhz to 50MHZ, but both traces kick laterally by about 2nS at 20MHz - otherwise their positions are quite stable.

One thing I did notice today, however, is that the Ch2 amplitude is about 0.15v less than Ch1's when set to 5v at 25MHz, when the channels are supposed to be in sync, and the difference appears to get bigger as the frequency increases.  I'll have to have another look at that to see exactly whats going on over the whole range, and see if other waveforms are affected.

Regards,
Dave
 

Offline plb

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #485 on: January 12, 2018, 06:37:55 pm »
Somewhat unnerving that its labelled as 12v but measuring 15.8V and has 16V rated output caps. They should be 25V rated.

These voltages may well be an issue. Mine are around 14V. The negative 5V regulator gave up the ghost, truncating the negative half of the output waveforms. Both it and the positive 78L05 got stinking hot in operation - I couldn't touch them for more than a few millisec- and the 100uF capacitors got uncomfortably hot. Replaced the negative regulator, then the positive one carked. Its replacement carked, so I mounted a TO220 7805 and ran wires to the SMD pads. Both the regulators are now tolerable to touch. I took the opportunity to replace the metal can caps with 25V tantalum/MnO2 types. They barely get warm. It's been running a couple of hours now. Fingers crossed.

And on another subject - if you ground the signal common, run the 3rd pin ground to the power supply board, not the main board, otherwise when you disconnect the power supply board from the main board it is easy to defibrillate yourself. (Ask me how I know...)
There is no technical fault too difficult to solve by sufficient application of marketing.
 

Offline Vytautas

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #486 on: January 12, 2018, 10:24:34 pm »
Not sure I agree to that.

There are some issues with this device, but the 4ns jitter? I strongly suspect that the 10x more expensive equivalent Rigol DG1062Z 60Mhz 2 channel AWG has the same issue.
So we are getting a more then we paid for.

In fact, all of the device is a good deal, with all quirks, even the leaky PSU, if you check price/performance to what said equivalent Rigol would cost.
Only the firmware-self-destruct is below par. So far below par I cannot advise the device till they have a warranty system.

Sorry. I expressed myself wrong. I meant that for this money you cannot expect it to be perfect. And yes, this generator certainly satisfies my needs. By the way, I replaced the power supply again. Or, rather, the transformers to one torroidal. Voltages are still +-15V. Also, replaced the 16V electrolytics to be sure with 35V ones (not SMD but through-hole ones; just soldered them on top and used some hot glue to fix in place). Now, somehow, the waveforms do not show ANY visible distortion at any settings. Even the slight distortions you saw in my previous post, are gone.
 

Offline cybermaus

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #487 on: January 13, 2018, 08:21:41 am »
Can you test this specifically with some frequencies which are whole divisions of the 250mHz clock. Like 50.00, 41.66, 35.71, 31.25, 27.77, 25.00 MHz

I did the measurements at the requested frequencies, a lot more carefully than the previous day's rough look, and took the average over four separate trials, after a 30 minute warm up period.  The Ch1 trace was centered exactly on the crosshairs at 25MHz, and the Ch2 lag time was measured at each frequency, the results being:

25.00MHZ   1.00nS
27.77MHz   1.00nS
31.25MHZ   1.10nS
35.71MHz   1.00nS
41.66MHz   1.10nS
50.00MHz   1.20nS

In fact, the relative phase shift was constant from at least 5Mhz to 50MHZ, but both traces kick laterally by about 2nS at 20MHz - otherwise their positions are quite stable.

One thing I did notice today, however, is that the Ch2 amplitude is about 0.15v less than Ch1's when set to 5v at 25MHz, when the channels are supposed to be in sync, and the difference appears to get bigger as the frequency increases.  I'll have to have another look at that to see exactly whats going on over the whole range, and see if other waveforms are affected.

Regards,
Dave

OK, I have a confession to make.
Just to dot the i's, I figured I also measure the delay on my device for all these frequencies. *and now I measure the same 1.2ns*

So I tried all sorts of things to recreate my original delay of 4ns. Long story short, I think I used cables of different length back then... |O
Sorry

However, the 4ns jitter (and its explanation of 250MHz DAC) stands. Just the phase difference does not, it is 1.2 and not 4 on my V3.1.
 

Offline DaveR

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #488 on: January 14, 2018, 03:50:31 am »
Yep, different length cables certainly make a difference - even 25mm, as I've just found out, is noticeable when the cables are swapped over.

I've also discovered that the 0.15v amplitude difference I was seeing was caused by the ultra-crappy BNC lead which Feeltech supplied: it's got twice the resistance of an RG58 lead of similar length, and probably a huge impedance difference as well.  The BNC connectors are so loose they won't lock onto the sockets properly, and one of them even pulls straight off!

It's prompted me check all my interconnect leads, and I've discovered that I haven't got a single pair of equal length and made from the same cable and fittings, so that's my next little tasklet for this evening....
 

Offline Vytautas

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #489 on: January 14, 2018, 04:51:28 am »
Damn Chinese piece of crap!!!
I was today using the fy6600 for some tasks and all of a sudden here what jumps out. The sine wave goes crazy. It is all over the place (multiple sine waves flashing all around) and the screen of the fy6600 starts showing all kinds of mess. The supply voltages are fine. Output amps seem to work fine, but there is something with the soft, I think. My version is 3.0. Damn Chinese crap. Does anyone have experience of FeelTech responding to these issues?
 

Offline DC1MC

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #490 on: January 14, 2018, 05:02:44 am »
You're done for it, as you can see the<firmware version 3.0 it's a time bomb, and yours just exploded.  :'(
Interested in joining the firmare reversing/extracted effort, because there will not be any trip to China and back for your device ?

 DC1MC
 

Offline rhb

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #491 on: January 14, 2018, 05:20:04 am »
I found I could use mine by resetting the idiotic values.  IIRC there is an ARB setting with a valid sine wave.  As for the rest, read my .sig :-(
 

Offline Vytautas

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #492 on: January 14, 2018, 05:22:04 am »
Sure I am interested.
What a nonsense those guys do not provide any support for soft upgrade!  >:( >:( >:(
 

Offline DaveR

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #493 on: January 14, 2018, 09:32:37 am »
Out of curiosity, Vytautas, why don't you give the "Help - Repair_Sine" option in the latest control software a try.  We don't know what it does yet, but my guess it was added in after it became known that 3.0 was a major problem, and this could be the fix for it.
 

Offline jleg

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #494 on: January 14, 2018, 08:32:15 pm »
Out of curiosity, Vytautas, why don't you give the "Help - Repair_Sine" option in the latest control software a try.  We don't know what it does yet, but my guess it was added in after it became known that 3.0 was a major problem, and this could be the fix for it.

No, this unfortunately is not the fix. Not sure, if this even is a fix for anything else...
The only thing  on my V3.0 which remained not being totally scrambled is functionality of channel 2. Since the display still is not of much use though, the PC software helps a bit controling the thing.
And in fact, after applying the „fix sine“ from the menu, also the sine shows up again. But unfortunately, this does not last long, nor does it survive a restart. So you end up applying this again and again...

P.S.: just for completeness - nothing heard back from Feeltech, no proposal or anything.
 

Offline Vytautas

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #495 on: January 14, 2018, 08:59:29 pm »
Just tried the "sine repair" thing. Thank you for notifying me.
Unfortunately, that is not repairing anything. Now I can control the sine wave from the PC and it works, when controlled by PC. But the rotary knob does not work for setting the frequency, it only controls the amplitude. The screen still has various signs on it. And other waveforms do not work in any way, neither when controlled from PC.
In a current condition its a 100 euro paper weight.  |O
 
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Offline soundtec

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #496 on: January 16, 2018, 06:39:34 am »
I saw the topic on FY6600 and signed up,

Thanks for all the great tips and suggestions ,

I just ordered one from ebay,

I was thinking ,a neat way to get galvanic isolation without completely replacing the psu with a linear one is to simply add a shaver transformer isolator socket to the enclosure 230/110-230volt ,plenty of room to mount the switch modes along side too .
Costs around 10 euros from my local electrical supplier .
I think two seperate switchmodes is the way to go ,one for the 5 volts and another for the +/- rails .Replacing the no brand psu caps with proper items should help a lot also. Rf and magnetic sheilding of the transformer and switchers might be worth doing as well as some extra LC at the dc outputs .
 


 
 

Offline soundtec

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #497 on: January 16, 2018, 06:45:04 am »
Common shaver type socket
 

Offline soundtec

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #498 on: January 16, 2018, 08:23:33 am »
Theres a chunky ground terminal on the transformer ,that could remain permanently bonded to mains earth . A 'system' ground switch could be placed between the ground terminal of the psu and mains earth,that way you decide if you want the unit grounded through the mains line or via the unit under test etc ,it allows ground loops to be  broken if the need arises .

I havent tried feeding a switchmode from a transformer before ,the windings will drastically limit the initial inrush current compared to direct mains connection ,probably no bad thing as the capacitor charge on regular wall warts etc creates quite a spark when they are plugged in ,something Ive never liked about switcher psu's .
 

Offline rhb

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Re: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
« Reply #499 on: January 16, 2018, 12:04:33 pm »
Why would you order one after reading about the FW issue?
 


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