Any reviews or experience with this function generator (MHS-2300A)?

[Pasky]

I'm just a hobbyist looking to get my first signal/function generator.  I saw this on ebay:

http://www.ebay.com/itm/5MHz-Arbitrary-Waveform-Dual-Channel-DDS-Function-Signal-Generator-Sweep-2-4-Lcd-/111242019491?pt=LH_DefaultDomain_0&hash=item19e68a82a3

The reason it interests me the most is the ability to create wave forms on the PC, and also it's compact size.  I know I can get a decent 2Mhz name brand generator from tektronix or HP, but I don't have the real estate for one of those dinosaurs on my desk at the moment. 

I tried searching for reviews for this, but couldn't find any.  Maybe someone here has experience with these?  The thing that worries me the most is the UI, I see some of the labels are in Chinese, a language I do not read/write .

[Pasky]

Anyone with experience with these FPGA signal generators in general then perhaps?  Are they usually accurate?

[Pasky]

Well, I ended up purchasing the 5Mhz model.  They also have a 10 and 20Mhz.  I'll try to do a tear down and take pictures when I receive it.

[electronics man]

I haven't got experience whith them but the seem to be from the onehunglow factory and you get what you pay for it may be better to get a secondhand proper function gen

[hedehede81]

Well, I ended up purchasing the 5Mhz model.  They also have a 10 and 20Mhz.  I'll try to do a tear down and take pictures when I receive it.

I've bought the 20mhz version and it didn't come with a software CD. Although the listing claims it can communicate with PC (and PC can control the instrument) and also receive arbitrary waveform data, I'm yet to find a software or serial protocol to send/receive data for this instrument. All I could find is Word document in Chinese which is the User Manual. Did you have any luck with this?

[hedehede81]

I've found the factory that produces these and spoke to their engineer on the phone. We had a communication problem but I hope I made my point. He said he'll send something to me tomorrow, will let you guys the outcome. By the way, the interface is fully English and very easy to understand. I can totally use it standalone without even a user manual. In fact I'm impressed with the unit on my first tests with a scope. But this unit is also fully controllable through serial commands (wave type, freq, duty cycle etc) and also receive arbitrary waveform data from PC and to do these we need more info. I hope what he'll send includes the serial protocol and PC software.

[hedehede81]

Well, I received user manual (English) and serial protocol (Chinese) from the engineer, and he also said that the software will be ready in a week or so. I was able to translate the serial protocol through Google Translate and now I'm able to change every setting from the PC (wave freq,amp,duty cycle, machine settings), can control the instrument remotely (start/ stop, even send keypresses) and upload arbitrary waveform. I haven't fully tested arbitrary waveform part and will write more when I do that.

[Pasky]

Please make a link to the software on here, as mine should be arriving sometime next week, thanks.

[hedehede81]

Please make a link to the software on here, as mine should be arriving sometime next week, thanks.

I'll link it when I receive don't worry. In fact PC software is redundant once you have the serial protocol, you can use this unit standalone or completely automate it from PC. I also succeeded uploading arbitrary waveform data from my PC, all you need is a serial terminal program. I'll give examples here if the software is not  ready when you receive your instrument.

[Pasky]

Great, I am a software programmer so that would work just as well.  Thank you so much.

[listener192]

Hi hedehede81,

I received the 5MHz version of the MHS-2300A and there is no operation manual. The manufacturers site doesn't allow a download of the manual, so would appreciate if you could forward a copy if its not too much trouble.

Thanks

[hedehede81]

Hi hedehede81,

I received the 5MHz version of the MHS-2300A and there is no operation manual. The manufacturers site doesn't allow a download of the manual, so would appreciate if you could forward a copy if its not too much trouble.

Thanks

Here is the user manual:
http://www34.zippyshare.com/v/22982647/file.html

[listener192]

Hi Hedehede81,

Thanks so much, appreciate the help!

Did you also have the remote commands either in Chinese or in English you could provide?

Thanks

[Pasky]

Excellent, thank you once again.

[hedehede81]

Hi Hedehede81,

Thanks so much, appreciate the help!

Did you also have the remote commands either in Chinese or in English you could provide?

Thanks

No problem guys, here is the serial protocol that I got Google translated into English:

http://www41.zippyshare.com/v/34191725/file.html

The commands are really easy indeed, you can change all the settings, generate keypresses,start/stop generator and upload arbitrary data remotely. Let me know if you have any questions.

[listener192]

Thanks again Hedehede81!

[Pasky]

Just got mine in the mail, and pretty impressed.  Just about all the signals are accurate except square.  I don't get a nice flat square wave, instead there is a sudden rise and then sudden drop, I'll post captures later, even at very low frequencies and amplitudes.  Do you also have this issue with the square wave?

Other than that, this thing is pretty nice.  I'll open it up when I have time and post pictures, I have the 5Mhz model.

[Pasky]

1Mhz Square, 5V Amplitude, 50% duty cycle:



10Khz Square, 10v, 50% duty cycle:



This is my first signal generator, but I imagine this is is sub par, when I see other signal generators producing a square wave, it's rather flat and well....square.

Everything else seems to work great however

210Khz Triangle Wave, 10V, 50% duty:



5Mhz Sine, 10V:

[marshallh]

Is teh voltage double what you specified? You mean need a 50ohm terminator.

[Pasky]

No. It's what I specified.

I took it apart and have some (what I feel are decent) shots of the construction.  It appears to be constructed rather well, I can't speak about the quality of chips used however, as this is beyond my knowledge.  I really love the interface, it's simple to use and makes sense.  My main reason for purchasing it, was I don't have the bench space for a nice traditional function generator, and I just wanted to do some testing with low/high pass filters and other things.  I do intend to get a proper signal generator and realize this is no replacement for one, but I feel like this thing will prove useful for my needs.

The anodized aluminum case is rather nice, it's pretty thick, doesn't feel like I could set something on it and it would begin to bend.  It's machined rather well.

It appears to use a resistor ladder for a DAC rather than an IC also. 

Anyways, here are the pictures of the innards:



LCD PCB:





Here's the (cheap,  LCMXO2-1200HC-4TG144C) FPGA it uses:





Near the DC adaptor plug:



Here's the heat sink removed where the 2 output channels are.  I'm unsure what these 2 chips are as the heatsink wore off the label:



Back of the main PCB:



I highly doubt the 10Mhz and 20Mhz model use updated hardware and it's just software locked.

[hedehede81]

That ICSP port looks real exciting.

[Pasky]

That ICSP port looks real exciting.

Does you square wave output also have overshoot and undershoot ?

[hedehede81]

That ICSP port looks real exciting.

Does you square wave output also have overshoot and undershoot ?

I'm not near my bench scope now, but my handheld scope shows some overshoot and undershoot with the square waves on high frequencies, yes.

[listener192]

Hi Hedehede81,

Having trouble understanding the trace mode functions. Seems that in ch 2 sync menu, Mode F has to be set to use ch 2 phase shift, to set phase shift between ch1 & ch2. Any idea what modes A & D  do? This is not covered in operation manual.

Also noticed that in ch 2 sync menu, changing ch 1 trace mode to Yes and back to No disables output. I could only turn off and on again to restore output. Once again nothing in manual about the purpose of this function.

Have you managed to figure it out?

Otherwise pleased with unit, although I wonder what the differences are between the 5,10 & 20MHz units.. software or hardware?

Thanks

[hedehede81]

I haven't had the the time to try the functions you suggested, I'll write here if I figure it out.

As for the differences in 5mhz and other models, I've opened up my unit (20mHz) and it looks totally same to me, I think there should be a software lock.