FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator

[Athanasis]

I didn't get it guys. Why don't you just leave this thing unmodified? Where is the problem?

[nctnico]

I didn't get it guys. Why don't you just leave this thing unmodified? Where is the problem?

Some people -like me- have the urge to improve things. Call it a mild form of OCD 

[masterx81]

I've ordered my FY3224S and i'm already studying on how to made it better. Linear power supply and/or plug with gnd is a must, then i was searching on how to increase the power output, the output amplifier is a unit gain buffer? Maybe this opamp should be adeguate:
http://www.ti.com/product/LMH6321
Can't wait to put my hands on it 

[classical]

Why don't you just leave this thing unmodified?

You are right. For most purposes it would work out of the box just fine. The capacitive coupling to mains is a good excuse to work on it. And many of us have fun doing something like that. Some want to do it right by setting up a solid power supply, other - like me - like to get rid of the leakage current with a minimum of effort. suum cuique.

[pascal_sweden]

What about the other improvements, like improving the quality of the signal output?
Power circuit as such, is a NICE to have improvement, but further improving the signal output is more MUST have

[Athanasis]

Thanks for your replies guys.

pascal_sweden note is also important.

[bitseeker]

I've been unwell last week so didn't get chance to do the next video on USB isolation - hopefully I'll get something out this week.

Sorry to hear that, Steve. Something's been going around here as well. So far, I've dodged it. Hope you're feeling better soon!

[bitseeker]

I didn't get it guys. Why don't you just leave this thing unmodified? Where is the problem?

Problem? Quirk? Bug? Deficiency? It depends on how you look at it. The bottom line is that this device can be better than it is and it doesn't cost a lot if you blow it up. So, it's a prime candidate for tinkering, whether you're doing it to learn, entertain yourself, help the community, etc.

[electronauta]

[ftp]Hello and sorry for my bad english. This is my first message here.

The power supply of my unit has +5V, +12V & -12V outputs, but only +11V & 11V are developped. So, the output at 20Vpp is slightly cutted in open ouput and the same at 8Vpp about 50 ohm load.
I thought rise turns number of +-12V coils, but this is hard and dangerous (transformer broke).
Finally, I changed the schottky diode of +5V output for a series group of four similar schottky diodes. This action rise voltage of +5V coil (not in the +5V out) in 1V aproximately and proportionaly in +-12V coils.
The ouput in +-12V outs is +-13V now and ouput in open circuit reach 20Vpp and 11Vpp about 50 ohm  without problem.
More diodes rise more voltage but this could be dangerous for the output opamps. I reached +-18V but I went backwards.
The supply runs at 330KHz and is good idea to use only scottky diodes for this mod in +5V out.

The trigged output of certain number of pulses on main output (burst) is ok for peak audio power of amplifiers.

TTL out have very small rise time and is ok for longitude and impedance tests in transmission lines (TDR) with 1MHz and 1% duty.

Javier Muriedas (EA1AWY)

[Forser]

Is there any advantages to modifiying this unit as SteveyG did in his Youtube video if you don't have grounded wall sockets?

Best Regards
Marcus

[classical]

That depends...
In your situation I would measure the voltage and the current between the signal generator and the BNC jack and my oscilloscope or power supply or other units I have on the bench. If there is no high voltage and just a few µA I wouldnt worry about threatening my DUTs.

On the other hand the insulation of the wires of built in transformer dos not look too good. So, an additional isolation transformer at least improves your personal protection against electrical shocks if the built in transformer would fail.

[Forser]

Don't have the unit yet, haven't ordered it.

My Oscilloscope is connected to a PeakTech AC Power Supply which is an Isolation Transformer.
Overkill i guess but since don't have Ground Outlets in the apartment except Bathroom / Kitchen and i got it as a gift, i decided to use it to keep the Scope a bit safer.

Will most likely order the Function Generator plus the stuff that SteveyG are using.

Thanks for a quick response!

[nctnico]

If you don't have outlets with ground then the best thing to do is to get a power distribution bar with grounded outlets. Then at least all the grounds of the equipment is connected together. The residual AC voltage on a piece of ungrounded equipment is powerful enough to damage an input of a chip.

[Forser]

@nctnico, Yeah, Power Supply and such are connected to a power bar so they are on the same ground loop, including the Isolation Transformer is on that.

[electronauta]

Gby said:

"Just for fun I made an 2048 point waveform that is 10 sine cycles. This way when commanding 6 MHz you actually try to output 60 MHz. I would say using this technique you get usable output up to the full FY3224S product of 24 Mhz. Above 30 MHz the amplitude drops and the phase lag increases rapidly. Below are my test results: "

I'd like know how you are do it and if you would put the file here.
Thanks

[gby]

electronauta,

I used a spreadsheet to make two columns of data.  The first was just in numerical order and the second used a formula to create the value.  The FY3200 expects the following for arbitrary waveform data:
   1.  2048 points.  So the first column was numbered 0 to 2047
   2.  Waveform values to be between 0 and 4095 (12 bits)
   3.  0 corresponds to minimum Vout, 2048 counts correspond 0 Volts, and 4095 corresponds to maximum Vout

Assume column A is the 0 to 2047 numerical sequence and column B will be the arbitrary wave value.  To get my example of 10 sinusoidal cycles over the 2048 points I used the following formula:

   value in B1 = 2047*sin(10*A1*pi()/1024) + 2048

I attached a simple spreadsheet I made to do the above for anyone that wants to use it.  This spreadsheet allows you to set the number of sine cycles and the phase that it starts at.

To get this waveform into the generator I used the Feeltech PC software.  In the spreadsheet I copied the data column and in the Feeltech software I pasted the data.  More specifically, in the Feeltech software I clicked on the "Text Window" tab and I pasted the data in the large blank text box.  If you do this step correctly you should see the waveform shown in the graph in the lower right hand corner.  The last step is to click the send button to get the waveform to be sent to the FY3200.

Please note that I was not able to get this software working to send the arbitrary waveform until I had just the right driver installed on my PC.  Please my earlier post on page 1 on this thread for details.

Hope this all helps.  Have fun.

gby
 

[gby]

electronauta got my interest in this generator again.  Earlier I had noted that the USB interface is just a USB to TTL serial converter chip.  To eliminate the wired connection to the PC I modified my generator to install a Bluetooth to serial adapter.  Specifically, I used a JY-MCU Bluetooth board that are sold for use with Arduinos.  They are inexpensive and readily available from ebay and other sources.  I bought mine from DX.com:
 (http://www.dxsoul.com/product/jy-mcu-arduino-bluetooth-wireless-serial-port-module-901104299?utm_source=dxsoul&utm_medium=edm&utm_campaign=20141028GEEKdxsoul#.V1wXoMUeRv8).

I installed it with a toggle switch between the generator and the Bluetooth module, builtin the USB interface so that I could switch between the two.  Using a serial program like Putty or writing my own programs in Python I was able to wirelessly talk to the FY3200 over the Bluetooth COM6 virtual serial port.  It worked great.  Unfortunately, the Feelttech PC software would never connect over the Bluetooth virtual COM6 port.  The software works perfectly over the USB virtual COM3 port.

Now, my questions for the forum. 
   1.  Any suggestions on how to get the Feeltech PC software to work with the Bluetooth COM port??
   2.  I have one of the older FY3206S generators from summer 2015 that powers up saying ver 1.2.  My Feeltech software was installed from a version labeled FY3200PC SoftwareV1.3.exe.  Is there a newer version of the Feeltech software that people find works with the original ver 1.2 unit?  I would like to try a newer version to see if I can get it working over my Bluetooth wireless mod.

gby

[bitseeker]

gby, that's a very cool idea to slip in a TTL-to-Bluetooth interface. I'm not sure why the FeelTech software won't work with it. Perhaps it's not happy with the higher COM number, though that seems a silly limitation if it is the problem. Are you able to force the Bluetooth interface on the computer down to COM3 or the USB interface up to COM6 to see if it makes any difference?

[pascal_sweden]

I think it should be fairly easy to write an Android application that uses Bluetooth to interface with the FeelTech signal generator.

Another alternative is to use the FT311D or FT312D chip from FTDI that provides a USB host to your Android phone or tablet device, based on the Android Open Accessory mode that is supported since Android version 3.1 and onwards.

As there is enough space available in the FeelTech signal generator, you could even build in the FT311D Evaluation Board, and make the USB port available on the outside of the device.

http://www.digikey.com/catalog/en/partgroup/ft311d-evaluation-board-umft311ev/33342

This would provide Android support to your FeelTech signal generator.
It would highly increase the value of your signal generator!

Here is a nice tutorial from DigiKey about Android Interface Solutions:
http://dkc1.digikey.com/us/en/TOD/FTDI/Android-Interface-Solutions/Android-Interface-Solutions.html

Enjoy!

[electronauta]

Thanks for your detailed message, Gby.
I'm a informatic (and english speaker) dummy, but I'm going to try. I will comment the results.

[SteveyG]

I installed it with a toggle switch between the generator and the Bluetooth module, builtin the USB interface so that I could switch between the two.  Using a serial program like Putty or writing my own programs in Python I was able to wirelessly talk to the FY3200 over the Bluetooth COM6 virtual serial port.  It worked great.  Unfortunately, the Feelttech PC software would never connect over the Bluetooth virtual COM6 port.  The software works perfectly over the USB virtual COM3 port.

I'll try using an FTDI converter in place of the CH converter to see if the software works with that - I'd be surprised if they are looking at any serial numbers or enumeration of any particular device.

Another thing to try would be to download some serial port sniffer software to see if they're doing anything special which the Bluetooth converter doesn't support. 

[bitseeker]

Stevey's got another vid update: cool ventilation mod, USB isolation, tinkering with the PC software:

[pascal_sweden]

The FeelTech FY3224S is a bench type signal generator.

FeelTech also produces a portable non-bench type signal generator with a colour screen, the FeelTech FY2300:

http://en.feeltech.net/html/Signal%20generator/show_17.html

I wanted to point out here that FeelTech has recently released an improved version of their portable non-bench type signal generator, the FeelTech FY2300H:

14-bit D/A converter, 250 MSa/s sample rate, 8 Mpoints sample memory, 0.1 deg phase resolution
Improved power supply design to reduce noise on the signal output

http://en.feeltech.net/html/dynamics/show_49.html

Personally I like the FeelTech FY3224S bench type signal generator better, as it better suited for a lab environment.

Maybe they will release a FeelTech FY3224H as well in the future
That's why I wanted to share more info about the non-bench type signal generator in this thread.

[classical]

Here is my solution to reduce residual voltage and leakage current:

Not as perfect as Steve's solution, but simler, cheaper, faster. And does not need a fan.

[Candid]

Looks nice. Some info about the used parts and sources (Conrad? eBay?) and a circuit diagram would be helpful.