Author Topic: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator  (Read 40215 times)

0 Members and 1 Guest are viewing this topic.

Offline bugi

  • Regular Contributor
  • *
  • Posts: 139
  • Country: fi
  • Hobbyist using the ultra slow and unsure method
Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #175 on: April 14, 2018, 06:27:30 pm »
It seems that the change 1 suggested by takfuji should be also done on the -12V (or -12.5V judging by the resistor ratio?) rail, it is basically identical with the positive side (other than the charge pump series capacitor in between).

I noticed some additional points to improve, like one opamp missing a positive supply cap and a shared opamp having (likely) much less supply cap than suggested in datasheet for the marketed crosstalk figures, but their effects are still only at maybe/theory level, I haven't had time to test/measure those yet.
 

Offline hector.pascal

  • Contributor
  • Posts: 15
Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #176 on: May 30, 2018, 05:33:23 pm »
Hi everyone,
Could some kind person please look at the 5V smps PSU sent with their JDS6600 and tell me the output current rating printed on the label.  It's not actually given in the manual.
I've got all my 5V "wall-wart" supplies totally mixed up, and want to label the correct one.
Thanks!
H-P
 

Offline bugi

  • Regular Contributor
  • *
  • Posts: 139
  • Country: fi
  • Hobbyist using the ultra slow and unsure method
Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #177 on: May 30, 2018, 05:49:04 pm »
Here's a photo of the thing.
 
The following users thanked this post: hector.pascal

Offline hector.pascal

  • Contributor
  • Posts: 15
Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #178 on: May 31, 2018, 03:37:14 pm »
Many thanks BUGI   :-+
I have both updated my manual, and also saved your photo.
H-P
« Last Edit: May 31, 2018, 03:38:53 pm by hector.pascal »
 

Offline hector.pascal

  • Contributor
  • Posts: 15
Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #179 on: June 05, 2018, 02:10:49 am »
The one thing that REALLY bugs me is the button labelled, "AMPL" that changes the voltage value displayed (e.g. the 5V appearing after bootup).  This is because the value is actually the peak-to-peak voltage of the sinewave shown on the screen - not its AMPLitude!   So in fact the output is really v(t)=2.5sin(wt) volts into a high impedance.   This confused me quite a bit initially!  If there is room on the screen, a little "ptp" added after the V symbol would help a lot.
Also, my unit rather annoyingly gives out 5.24Vptp into hiZ when set to 5.000V @ MHz frequencies = a +4.8% error!   This makes a nonsense of having voltage resolution settable to 1mV!   This 5.24Vptp value was confirmed correct by re-calibrating a new HP54645D, a TDS210 and a Rigol DS1102E just before measurement.  In addition I also checked each scope's DC calibration using an AD584JH precision voltage reference!  (Terminating at the scope input with 50\$\Omega\$ just halves this value as expected).  I'd love to know how to correct it - hopefully it's only a pot adjustment, when I get brave enough to open the box!  Anyone know how?
But otherwise, at the price, the JDS6600 is a pretty good piece of equipment for non-professionals.   Yes, it has some deficiencies, but to compare it to $$$k truly professional equipment, as others have tried, is not fair to the designers.
H-P
« Last Edit: June 05, 2018, 02:20:05 am by hector.pascal »
 

Offline bugi

  • Regular Contributor
  • *
  • Posts: 139
  • Country: fi
  • Hobbyist using the ultra slow and unsure method
Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #180 on: June 05, 2018, 04:37:44 am »
Afaik, the most common "symbol" for peak to peak voltage is "Vpp" (without the t between p's). The amplitude vs Vpp is one of the quirks I have planned to print on a sticker to be on top of the unit.

tjones99 noticed the amplitude/voltage error earlier, but there hasn't be any hints how to adjust it so far.
 

Offline EmbeddedRT

  • Newbie
  • Posts: 1
  • Country: us
Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #181 on: August 22, 2018, 07:29:36 am »
Hello
I want to buy one 60MHz function generator
but what's the difference between Feleltech, Kuman, JDS, Koolrtron 60MHz function generators?!!
for example I found the below device:
https://www.amazon.com/gp/product/B07596133Q/ref=ask_ql_qh_dp_hza

I don't know what I should do!
actually I should tune my medical board (Step response and Frequency response) and I need such a device   :bullshit:

Best Regards
Hi friend
thank you for your message and your question
about Kuman, JDS, Koolrtron, they are from same designer . our engineer and Minghe engineer design the JDS6600. other Kuman and Koolrtron should use the brand.  JDS6600 is newest version.
about the link, it is also new . it is a hand-held, JDS6600 is desktop. data and function are same

----------------------

RD Tech - I have, regrettably, already ordered a 30Mhz "koolertron" off Amazon before finding this forum.  There are a few posts with some issues like phase changes when running 2 channels, and the unit powering off by itself after a while.

Is there anyway to determine how old the HW or firmware or SW is in mine - to determine if its worth returning the unit in order to buy one from 'aliexpress' that has more recent updates?

Already found out that mine shut itself off after a while the first time I powered it on and so I'm letting it run again to see if it does that on a regular basis. 

That is going to be a problem if I can't let it run continuously - is that a bug that has been fixed in a newer version?  If so can mine be updated or do I have to return it and buy a newer issued unit?

Thanks for the help and all your info provided to the forum on your product!

 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf