Author Topic: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator  (Read 259642 times)

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Offline Muttley Snickers

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #250 on: May 11, 2016, 09:22:04 am »
That was a great video.   :-+

Two things that still have me stumped though.   :-//
1. Did you ever work out what the batteries were doing in the box ?
2. Why the hell have I not yet subscribed to your channel ?
It's up the top in my favourites list and I've been a fan for quite a while, I will get this looked into and rectified immediately, no excuse for it at all. I have a big list of stuff ready to order from Bangood and it's nice to see them giving some back by supporting you and hopefully taking notice of your findings.

Thank you, well done   :)
 

Offline SteveyG

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #251 on: May 11, 2016, 09:32:32 am »
That was a great video.   :-+

Two things that still have me stumped though.   :-//
1. Did you ever work out what the batteries were doing in the box ?
2. Why the hell have I not yet subscribed to your channel ?
It's up the top in my favourites list and I've been a fan for quite a while, I will get this looked into and rectified immediately, no excuse for it at all. I have a big list of stuff ready to order from Bangood and it's nice to see them giving some back by supporting you and hopefully taking notice of your findings.

Thank you, well done   :)

The batteries are a complete mystery! Looks like someone accidentally packed them in the box.

The plan now is to modify the sig gen with a linear power supply and also add in an isolator for the USB connection.

Thanks  :-+

Offline Forser

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #252 on: May 13, 2016, 08:27:32 pm »
@SteveyG, Would you recommend that function generator for a beginner that is following along the Learning Arts of Electronics book? I noticed that the book is using both an Scope and Func Gen on a lot of the labs and this seems like a decently priced one for a person on a small budget.
 

Offline FlyingHacker

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #253 on: May 13, 2016, 11:31:27 pm »
I would recommend it for you. It would probably be a good idea to put a linear power supply in it, but it is a great unit for the price.
--73
 
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Offline Texacate

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #254 on: May 14, 2016, 03:08:47 am »
SteveyG,  let us know if you find a small, economical linear power supply capable of +5v +12v -12v.  The only ones I know of are targeted toward the eurorack modular analog synthesizer market. And those only meet the "small" criteria.  They cost more than this function generator does.  My thoughts were using a +/- 15V switching supply (such as Meanwell PD-2515) followed by some LM7812s and a LM7805.  But I guess I'm a still a bit unclear regarding the value a linear supply would add to the FY3224S, over the switching power supply it already has.  Is there a particular performance spec that would benefit if you replaced the switching power supply with a linear one?
 

Offline SNGLinks

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #255 on: May 14, 2016, 03:23:49 am »
SteveyG,  .  But I guess I'm a still a bit unclear regarding the value a linear supply would add to the FY3224S, over the switching power supply it already has.  Is there a particular performance spec that would benefit if you replaced the switching power supply with a linear one?

A linear supply would give complete isolation from the mains.
 

Offline FlyingHacker

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #256 on: May 14, 2016, 03:30:56 am »
I am putting together a supply based on one of these for the +/-12v and a regular LM317 module for the 5V.

http://www.ebay.com/itm/172120955716?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

All this connected to a 15V transformer through a mains fuse. Separate switch to control earth ground.
--73
 

Offline Texacate

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« Last Edit: May 14, 2016, 04:37:50 am by Texacate »
 

Offline FlyingHacker

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #258 on: May 14, 2016, 05:05:46 am »
I got a $3 one from my local store. I do need to measure the current the FeelTech uses. Have you done so?

I think a 5W tranny would likely be way overkill. But better to overbuild than to under build. Again need to measure the current to decide if mine will work or not.
--73
 

Offline Texacate

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #259 on: May 14, 2016, 06:30:54 am »
I have never directly measured the 12v supply current.  I did measure the AC power on the mains with a watt-meter one time.  As I recall it was ~0.5W idle, and ~3 watts driving only one channel at 10v p2p sine into into a 50 ohm load.   

Looking at it from a completely different angle:  Its pretty easy to calculate worst-case power needed to drive the BNC outputs.  I don't recommend actually doing this but... Assume we abuse the thing and make it drive +10V DC (open circuit), but short the BNC outputs with nothing but the FG's internal 50 ohm impedance to regulate the output current. That works out to 200mA of current, or 2 Watts per channel, times two channels = 4 Watts total.  If we're not quite that abusive, and always use 50 ohm minimum load, then the max power needed by the output drivers drops from 2W per channel to 1W per channel = 2W total.  Throw in another watt for losses, the FPGA, and the display and such, and you're back up to ~3W.

Im guessing a 5W transformer would be in the right ball park.
« Last Edit: May 15, 2016, 03:31:15 pm by Texacate »
 

Offline Forser

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #260 on: May 14, 2016, 10:54:46 am »
I would recommend it for you. It would probably be a good idea to put a linear power supply in it, but it is a great unit for the price.

What would be a good linear power supply? I am in Europe and i don't have ground wall plugs except Kitchen / Bathroom.

Best Regards
Marcus
 

Offline pascal_sweden

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #261 on: May 14, 2016, 06:13:03 pm »
I remember that in Sweden! :)

In Norway it is actually a harder requirement, ground plug everywhere. Just like in Belgium!
Sweden is a bit behind here =)
 

Offline Forser

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #262 on: May 14, 2016, 06:20:43 pm »
I remember that in Sweden! :)

In Norway it is actually a harder requirement, ground plug everywhere. Just like in Belgium!
Sweden is a bit behind here =)

I think new production has requirements of ground plugs everywhere.
Think it was enforced at the 90s, but i am not 100% sure about that.
 

Offline SteveyG

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #263 on: May 14, 2016, 06:48:57 pm »
SteveyG,  let us know if you find a small, economical linear power supply capable of +5v +12v -12v.  The only ones I know of are targeted toward the eurorack modular analog synthesizer market. And those only meet the "small" criteria.  They cost more than this function generator does.  My thoughts were using a +/- 15V switching supply (such as Meanwell PD-2515) followed by some LM7812s and a LM7805.  But I guess I'm a still a bit unclear regarding the value a linear supply would add to the FY3224S, over the switching power supply it already has.  Is there a particular performance spec that would benefit if you replaced the switching power supply with a linear one?

I'm just recording some of the bits for the next video. My plan is to use a small transformer and some regulators. I didn't see any off the shelf linear modules with the voltages we need.

The main reason for the linear supplies is because the transformers provide proper isolation from the mains. The leakage currents from the switching power supply on these units may cause damage to your circuitry.

Offline pascal_sweden

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #264 on: May 14, 2016, 06:54:48 pm »
Linear power supply has also disadvantages, isn't it?
 

Offline SteveyG

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #265 on: May 14, 2016, 07:09:02 pm »
Linear power supply has also disadvantages, isn't it?

Efficiency, size, weight and maybe cost.

Offline FlyingHacker

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #266 on: May 15, 2016, 02:28:31 am »
Steveyg: Do you see those lm317/lm337 eBay modules I posted earlier in this thread. Should let you get +/-12V from your transformer rather easily and cheaply...

Love your channel, BTW.
--73
 

Offline bitseeker

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #267 on: May 15, 2016, 03:18:22 am »
Looking forward to your linear supply upgrade, Steve.

What frequency reference does this generator use and would it be a major undertaking to swap it out or hack in an external reference connection? I have an OCXO in my counter that would be nice to pipe into the generator.
I TEA.
 

Offline pascal_sweden

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #268 on: May 15, 2016, 03:37:41 pm »
Looking forward to your linear supply upgrade, Steve.

What frequency reference does this generator use and would it be a major undertaking to swap it out or hack in an external reference connection? I have an OCXO in my counter that would be nice to pipe into the generator.

bitseeker = Frequent Contributor and Creative Contributor  :-+
 

Offline bitseeker

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #269 on: May 16, 2016, 12:46:12 am »
Thanks, Pascal. If only I had enough time to implement what's generated by that creativity. At least there's no shortage of things to make, hack or otherwise improve. ;D

This unit is a cool platform for tinkering. An external clock input would be quite nice.
I TEA.
 

Offline FlyingHacker

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #270 on: May 16, 2016, 12:50:18 am »
If I recall the clocking is handled by the FPGA (which has its own crystal, maybe 24MHz, don't recall), not by aseparate timing crystal per se. Making it really difficult to convert for an external clock.

Anybody confirm this? It was a while back that I checked.
--73
 

Offline SteveyG

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #271 on: May 16, 2016, 07:56:19 pm »
If I recall the clocking is handled by the FPGA (which has its own crystal, maybe 24MHz, don't recall), not by aseparate timing crystal per se. Making it really difficult to convert for an external clock.

Anybody confirm this? It was a while back that I checked.

It looks like the 24MHz crystal is shared between the FPGA and the MCU. An external reference may be possible with a PLL though, although I don't have enough time for that modification just yet.

Offline bitseeker

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #272 on: May 16, 2016, 08:47:44 pm »
No worries. Good to know it's possible!
I TEA.
 

Offline classical

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #273 on: May 21, 2016, 02:56:17 am »
Regarding the 1mA leakage current from mains an a new inear power supply: I found an old 220V / 220V  isolating transformer in my stock. This at least can reduce the issue without any changes within the units. The transformer is way too big (60VA) and has a leakage current of ca. 50µA, probably due to capacity coupling from primary to secondary. It is a one chamber transformer.
Maybe we can find a smaller and cheap isolating transformer, if possible with two chambers.  Ore maybe two cheap mains to 15V or so in serie circuit (mains -> low voltage -> mains).
 

Offline bitseeker

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Re: FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator
« Reply #274 on: May 21, 2016, 05:45:56 am »
SteveyG's linear power supply mod is up now:



How is the heat build up inside the case? I didn't see much in the way of ventilation. Are the slots on the side open? They looked decorative, but could be cut open.
I TEA.
 


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