Author Topic: FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator  (Read 549227 times)

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Offline SMB784

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Boy, that's much better but the amount of jitter in that oscillator is unbelievable.

Interestingly enough, the square wave (jitter only arises in square wave signals) jitter specs are competitive with if not entirely better than any of the lower spec (but much higher price) signal generators from HP, Rigol, and Siglent

Facts and fictions are not often equal. Do you have any data behind your claim or is just trumpth instead of truth.
Manufacturer is perhaps not interest about facts (ref. published some kind of details/specs) but if any other have facts, please do not hide facts.


Where I can find manufacturer published FY6600 jitter specifications based to reliable measurements for Square wave (or what ever wave) or even somehow trusted third party measured data.

Example Siglent low end SDG1000X series:'
Square wave and Pulse Max (aka worst case)
Jitter (rms), Cycle to cycle 300 ps + 0.05 ppm of period



In this image just one real measurement for simple example. (freq selected so that it is not any "golden" freq related to reference and/or sampling rate (what is 150MSa/s in SDG1000X)
Of course Arb have cycle-cycle peak peak jitter 6.7ns (1000/150) excluding some "golden" special frequencies. Also triangle wave have this jitter. This is more (worse) than 4ns what is sampling period based jitter in FY6600 (what is FY6600 real total cycle-cycle jitter is unknown least for me without any real trusted measured data)
Note that in example image have sum of all errors, not only generator. With this level of jitter there come also oscilloscope trigger jitter, noise and timebase jitter must be taken into account. Only what can say is that SDG jitter is unknown amount less than total jitter displayed in image.

I understand your reticence to believe what I said about the jitter specs, but what I am saying is not just pulled from my ass, it's read directly off the data sheet of the devices that I have listed (and provided links to) in my posts.

Those are the maximum jitter specs claimed by the manufacturer. If you actually possess those devices (ideally multiple devices of the same model number for each model number) please test them, your input on the jitter specifications would be most valuable. After all, more data is better than less data.

Offline kahe40

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seems like the Siglent-dealer parse this entire board,
and whenever the single magic word 'Siglent' is spoken,
they are on board and enlighten you...

@rf-loop takes the new SDG1060X (X suffix!!!) worth 500€
and compares it to 85€ FY6660 - makes it sense?
OK, Square has nearly no jitter, other Waves have ~7ns ,
Feeltech has 4ns and this is less, or not?
So @SMB784 is right, this is 'entirely better'

And all the allready sold old Siglent 800 or 1000 without 'X'
and Rigols and so on with 100 or 150 MSa/s
are worser than Feeltech with 250 MSa/s.
This is exactly what @SMB784 said.

This is what Siglent says:

edit, image added
« Last Edit: June 11, 2018, 05:07:21 pm by kahe40 »
 

Offline rf-loop

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seems like the Siglent-dealer parse this entire board,
and whenever the single magic word 'Siglent' is spoken,
they are on board and enlighten you...

@rf-loop takes the new SDG1060X (X suffix!!!) worth 500€
and compares it to 85€ FY6660 - makes it sense?
OK, Square has nearly no jitter, other Waves have ~7ns ,
Feeltech has 4ns and this is less, or not?
So @SMB784 is right, this is 'entirely better'

And all the allready sold old Siglent 800 or 1000 without 'X'
and Rigols and so on with 100 or 150 MSa/s
are worser than Feeltech with 250 MSa/s.
This is exactly what @SMB784 said.

This is what Siglent says:

edit, image added

Square wave. My comment was, as I underlined in my answer just for Squarewave. Because  this was told is as good as in Siglent or far better. And this was false. (exewpt some ancient many years old models)
And then I also told that pulse also have this low jitter. (wjat jitters are not even specified in FY information.
Also, if you have read, I tell that Triangle and Arb have more jitter, 6.7ns vs 4ns in FY6600.  Of course this one clock jitter (what is only part of total jitter)  in FY6600 is better due to higher samplerate. (if Arb is important). In my world, most important is Sine, Square and pulse functions signal quality. (including pulse width fine adjustmet and rise and fall times adjustment with low jitter.)
btw, it was not SDS1062X. How you think so? There on front panel read 1032X. Price 339 EUR. Worth for every cent. Also it have CE cerified (and in this case it is not only manufacturer own promise, it is fully inspected in independent accredited laboratory with full documents what is base for CE certification, what makes it possible for EU area markets. It is also safety question. 
FY6600 have not passed any this kind of inspections as far as I know. It is only lazy customes officers these can flow inside EU area.
This is also (just one) reason why there is not any company in EU who sell these to end users.

I have not told that FY6600 is total crap junk and not worth for its price in low end hobby use /if user take full care about electric safety) but, wrong claim is wrong claim and they are good to correct. And it was about square wave jitter. NNC

« Last Edit: June 12, 2018, 06:39:02 am by rf-loop »
I drive a LEC (low el. consumption) BEV car. Smoke exhaust pipes - go to museum. In Finland quite all electric power is made using nuclear, wind, solar and water.

Wises must compel the mad barbarians to stop their crimes against humanity. Where have the wises gone?
 

Offline kahe40

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Thanks, rf-loop. Price was for 60MHz model to compare, anyway as you sayed,
for hobby or as a toy, it is worth the pain.

By the way, do you know more about the EasyWave technology from Siglent ?
How can they avoid this clock-jitter ?

 

Offline SMB784

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Here is a short explainer on Siglent's EasyPulse technology that reduces Jitter (and other things): Siglent's EasyPulse

Maybe we can figure out how they do this. Maybe it's in the FPGA firmware, maybe it's a separate hardware module. Either way, maybe we can make it ourselves!

Offline rhb

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Well, after 7 months.  I finally got a replacement front panel.   With V3.1 FW!!!!
 

Offline soundtec

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Glad you finally got a result RHB, better late than never as they say , that was a hell of a lot of  |O , takes persistance ,hopefully it all works out from here on.
 

Offline cybermaus

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Amazing. That you got a front panel at all.

That it is not the latest but V3.1 is annoying of course, but so is mine, it works fine. Disspite what people keep saying, only V3.0 has the self-destruct. V3.1 only ever had reports of loss of Sine, but that is recoverable.
 

Offline rhb

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I had to lean on them very hard, which is something I dislike doing.  I'd like to get a PM from anyone who has a V3.0 unit.  I don't want to explain publicly.

I bought a used 33622A from Keysight's eBay store.  If F***Tech will replace the front panel for the other people with V3.0 devices, I'll do a detailed performance comparison of the FY6800.  In light of the roughly 60x price differential the unit should come off looking very attractive.
But I am completely unwilling to do anything that would increase their sales until they behave better.

The really sad part is that if they provided decent support and entered into exclusive distributorship arrangements in NA, EU and a few other areas, they could sell it at $200-250 retail as fast as they could make them.  They would leave Rigol, Siglent and  Instek scrambling to recover.  The F***Tech is an interesting commentary on the unit margins for making low end Chinese T&M gear.
 

Offline soundtec

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Nasty surprise in the mail this morning ,a letter from Fed-ex demanding I pay import tax/duty on the free FY6800 I got from Feeltech.
Does anybody here have any idea of the legalities of this situation I find myself in ?
Posession is 9/10 th's of the law ,I paid zero for this machine, it was a prize and there is no bill of sale or invoice.
I could try arguing my case with fed-ex or I could just put the letter in the bin and see what happens ,they of course could set debt collectors on my trail ,which wouldnt be much fun ,but my guess is there chancing their arm trying to pin this on me ,maybe they should give Feeltech a shout with a demand for money and see how they get on  :-DD
 

Offline rhb

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I don't know Irish law, but generally ignoring such things is not a good strategy.  I'd suggest responding that you received the item  to do a review of its performance and that as a consequence there is no invoice.  Generally a "prize" is often taxable.  I'd suggest a letter  along the lines of:

To whom it may concern:

I received this unit from the maker for the purpose of  an extended  technical review of its performance.  As a consequence there is no bill of sale or invoice.  I do not think it should be subject to customs duties.

Regards,


Basically, tell them it's on loan from F***Tech.
 
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Offline soundtec

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Thanks for the advice RHB ,that sounds like a good approach , I'll fish out a few more opinions before making my mind up in any case ,
Cheers,
 

Offline DaveR

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How much are they asking for?  For the sake of 20 euros or so, I'd be inclined to save the potential aggravation this could cause and just accept that you got a nice new FY6800 very cheaply.  The 60MHz unit is currently selling for £100 - £110 on ebay from UK suppliers, so paying just 20% of that is still a damn good bargain.
 

Offline soundtec

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Thanks Dave,
Yeah ,the actual value is misquoted on the packaging ,in my favour ,but it still comes to 30 euros or so , I could just pay up and be done with it ,but if theres a creative accounting solution I would rather save myself the thirty eurobucks anyday.
Due to a dispute with the dept of social welfare here over biometric recognition , the suplementary payments I was getting on top of what I earn from self employment have been cut off completely for well over a year now ,of course the two things are completely seperate issues , but I loath paying over a red cent to a government who hood winked almost the entire population into being on a biometric database for which there seems to be no legal basis . Data protection comissioner was supposed to issue a report on the legality of this biometric system and the id card that goes along with it over six months ago ,but the release of the report keeps getting bounced down the line ,as far as I can see because it could show that the government were wrong on this.
 

Offline DaveR

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I understand your position entirely, soundtec!!  It sounds like the ID card scam the gov here were trying to inflict on us a few years back - £35 for a compulsory bio ID which would have been a colossal failure from the outset due to being too easy to duplicate - a fraudster's dream come true!  Fortunately, it was kicked into touch in 2010, but noises are now being made about resurrecting the scheme :(
 

Offline rhb

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An alternate phrasing:

"This unit is a factory demo unit provided for an extended technical evaluation."

That puts the problem in their lap.  And it's a factually true statement.  That is why you received it.
 
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Offline soundtec

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Yeah I did attend a public meeting late last year ,and there was a Scottish professor explained to the group all about the id card system in the Uk and how it fell apart. A government spin doctor had the gall to show up at the meeting too ,asking the question of the panel ,'Is there any right way of implementing this biometric data/card system ?' the panels response was a loud and clear no . Just as the meeting was winding up I asked the spin doctor ,'and your personal interest in this id/card system is ?' he looked up to heaven and walked out of the room ,much to the amusement of the panel ,was only later I realised he was one of the Taoiseachs(prime minister) chief advisers. :-DD

'factory demo unit' and 'extended technical evaluation' definitely two phrases I can use ,cheers RHB

 

Offline rhb

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FWIW

I've been looking at sine wave Lissajous patterns of the F***Tech and a 33622A at 10 MHz.  I see no conspicuous jitter, but the F**Tech frequency drifts quite a lot even over very short periods of time.  If I get them matched to 0.01Hz it drifts away in a few seconds.

I just checked using a square wave with the same result.   The 33622A spec is jitter <1 pS.

Obviously this is not a rigorous test, but it does suggest that the chief culprit is the reference oscillator and that a DIY oven would probably make a big improvement.
 

Offline soundtec

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I found it tends to stabilise after about 30 minutes ,and gets better when left on longer ,theres a few here who tweaked the clock alright ,definately seemed to improve matters .
 

Offline rhb

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I'm letting it warm up now hooked up to my 5386A  frequency counter.  I plan to make some observations over a couple of hours.  I wish I had a GPIB interface to automate readings.
 

Offline SMB784

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Are you using the stock oscillator in the FY6600? Upgrading to a TXCO really cleaned mine up

Offline rhb

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Yes this is the stock oscillator. and it is quite unstable.  What TXCO did you use?  How difficult was the installation?

I no longer really need the F***Tech, but it might prove handy to have if it is more stable.  It has certainly consumed a lot of my time.

The Keysight 33622A is really impressive, but it was over 30x more expensive and that was used from Keysight.  It's 1 GSa/S and goes to 120 MHz.  So really only suitable for professionals with business justification and old hobbyists with adequate discretionary funds.

I *really* wish that F***Tech would figure out that T & M gear and bare LCDs are not the same type of business and have to be conducted differently.  I think a 60 MHz FY6800 with proper support (i.e. repair depots in US, EU, etc.  real warranties rather than empty promises, etc)   would easily be worth $200-250  US retail.  But with their current business model,  buying one is just gambling.  There are not enough FY6800s in the wild to know how good they are.

 

Offline SMB784

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I used the D75J and it is rock solid. I will take some measurements with my spectrum analyzer and post it here tomorrow. It's an absolutely essential upgrade, and puts this device in the same class as many much more expensive devices from the other Chinese (or Taiwanese) manufacturers like Rigol, Siglent, and Instek.

A good switch mode power supply and ferrite, new output opamps, and a nice stable oscillator will run you about $50 and really put this device in a class of it's own

Offline rhb

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Did you post photos of the install?  The thread is beginning to compete with the $20 LCR tester ;-)

Not quite 33622A class though.  But I agree very good and much more affordable for the under 65 set.  I'll be very curious to see what people report about the 6800.  I *so* wish F***Tech would get their act together.
 

Offline Miti

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I did the following modifications, see the pictures:

1. Replaced the output op-amps
2. Replaced the power entry port
3. Replaced the stock oscillator with D75J
4. Replaced the 10uF/450V in the power supply with 33uF/400V Rubycon
5. Added one more safety cap in series with the existing one and connected the common point to earth GND
6. Added a 1M resistor from earth GND to GND
7. I added ferrite beads on +12V and -12V
8. Replaced the stock rectifier diodes with Schottky diodes

I tried to increase the capacitors in the power supply but it has a hard time starting, too much inrush and apparently this chip doesn't really have a good soft start.
The effect of all these changes, the jitter went way down to very acceptable values, the output BNC is at almost 0V with 1M to GND as I see in Agilent, the output level goes higher. Unfortunately the +/- 12V on my unit are only around +/- 11.4, otherwise it is not too bad. It can even supply an oven oscillator that I intend to add in the future.
« Last Edit: June 22, 2018, 11:01:13 am by Miti »
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