JDS6600 Function Generator Review & Teardown
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- Опубликовано: 22 июн 2017
- I take a detailed look at a cheap $100 function generator that came out recently, from JunCe Instruments.
Measuring amplitudes, checking harmonic distortion, making some funky waveforms, and seeing what's inside!
Looking at the 25MHz model in this review.
There are a few things I'd still like to test (i.e PC connectivity, measurement capabilities).
UPDATE: Upon request I've made some more measurements for the linearity, noise, slew rate; see website post.
Website post (and hi-res images): sebholzapfel.com/blog/jds6600...
Callsign: VK2SEB 
Наука
The state of the channels on power up are determined by the configuration that you have saved. You can set as desired (on/off) for each channel.
A really useful and helpful review - thanks!
vk2seb very good video I have the same model you have taught me quite a bit as I am just learning about waves and oscilloscopes. Many thanks for your time.
Great teardown! Did you notice any components which might convert one model (the 15Mhz) one to a higher frequency capable one? More often than not, the $40 difference in models is due to a $3 blocking diode, or even firmware :D
I never thought that is possible. Cool animation @ 4:56 :)
I have the 60M version of this Function Generator. I was concerned when VK2SEB said that his FG shut down after around 20 min. Fortunately, mine remained on until I manually turned it off. This clearly is not a high quality test instrument, hence the price. I enjoyed the tear-down and evaluation. For me, some times all one needs is just "good enough."
Thanks Folks,
KB1RGT
Hey Seb.
Mine arrived yesterday, (March 18) has the AU plug pack and got the 40MHz version when I order the 30MHz. For $91 delivered you can't go wrong. Cool review, Thanks.
Mick.
13:40 The 2 white circles on the board is where the SMD LED's are, if you remove the board, you can shove a small piece of black heat shrink over the 2 plastic tubes that molded on the frontpanel. That way, the markings CH1 and CH2 above the BNC's are nice lighted without illuminating the buttons above.
I have the same function generator but rebranded as Joy-IT, it came with exact the same contents in the box, except the cd, but Joy-IT offers this software on there website.
I also noticed, that the output voltage is very low current, barely enough to light up a white LED, even with a amplitude of 20V.
Great overview ! Do you have any mains leaking issue like in older feeltech Chinese signal generator
Thinking of getting one for aligning receivers. Other things to evaluate... What's the sine wave at the upper frequency limit like? Others report it being noisy, is the noise only a problem at higher outputs, say > 100 mV?
I would like to know more about the TTL pins on the back.
I bought the 60Mhz version of this a few months ago.
One main annoyance is when using gated pulse mode where you have it send a specific number of pulses. The default state is ungated. When it completes sending a number of pulses where it stops output and you go to change the number of pulses, it enables output ungated.
I was trying to test a binary counter that has a logic output at specific counts. Tried to use the generator to test it but could not.
Great review, thank you !
how you do that 7:41 make it pulse like that?? i have the fy6600 i need help
I'm interested in this little thing as my first function generator. Would you recommend this for someone just starting out in electronics? I've got some other gadgets from Ruideng as well, they sell (or maybe make? But I think just sell?) these units, that's how I found them. Love the other stuff. Nearly done building the DPS5020, fun little project that. Love the USB tester and dummy load, awesome stuff.
Also, did you happen to crack the power supply open? Even if you just say what is on the label, might give us an idea on how good it may or may not be. I have absolutely no shortage of 5v 2A power supplies, but it would be handy if the one included with the unit was usable.
Thanks for the video! Very informative!
This signal generator can do 4-20 mA current loop? thanks
Thanks for that tear. The Lattice is a beautiful chip, some have built in ARM processors on the same FPGA package not sure of that one..
DAC: I've got the simpler version of this...claims 12bit, which it is (discrete resistors like yours), but given the resistor accuracy (& FPGA outputs), you're lucky to get 8 bits.
Thanks for the review. Is this still the best bang for buck, or is there better in the $150AUD range? I have a Siglent sds1104x-e so I was wondering if this is ok or whether to just get the SAG1021? Did changing the wallwart solve the ground potential issue? Is it safe for scopes? Thanks.
Be sure to plug in the USB. That eliminates the 50+V leak and should clean up the noise. Doesn't matter if the host computer is on or off....still works (provided the host PC is grounded...duh).
does anyone know where to get software to use the usb on this?
can you vary any frequencey you wish
Does it have frequency sweep and sync output?
does 8MHZ sq wave look like sine
I have two requests. Does this have a potential on the ground line like the older and eerily similar FeelTech units and does this unit preserve your settings after power cycling?
Yes unfortunately there is a ground potential of 99 volts (!!) on my unit with the default plugpack (only found out after this video), so I switched to a different plugpack. One of the users over on the EEVBLOG forum (see reply #26 at www.eevblog.com/forum/testgear/anybody-know-anything-about-this-signal-generator/) reports the leakage current as 14uA. The unit can be set up to preserve your settings, but it does not do this by default (as you would have seen in the video). I later found that you can save your configurations into 'presets' and then select which 'preset' is loaded on boot...
Did you test the software to link it to your laptop. Necessary for creating the arbitrary waveforms.
I didnt get it to work on Windows 10
It comes with an external 5V PSU that does not connect to ground.
Thanks for this video. It doesn't look like it but can it generate an externally triggered pulse train ? (burst function)
Just tested this, seems to work: imgur.com/a/zzlyS
Alright, so the function seems to be there. Thanks
Do you have any info on running the burst mode of this unit? When I contacted Koolertron 'customer service' about this they responded by asking me to contact Amazon, the seller???? so much for customer service!!!
What is the frequency counter range and is it accurate?
I purchased this unit (60Mhz version). The one thing I don't like about it is that it is very noisy! Dial up an HF frequency on a ham band, and listen to it. Something should be done to clean it up! Is it the 5V supply or the switching supply inside to generate the voltages for the output amps (or both)? Otherwise it appears to be well made (the circuit board).
Thinking of getting one for aligning receivers. What's the upper frequency limit like? Is the waveform usable at 50mhz? Did you find a way around the noise issue? The wall wart can be replaced but is apparently does internal DC-DC conversion to get to 10v pp. Cant fix noise on that. Is the noise only a problem at higher outputs, say > 100 mV?
Will that work for CD radio or the 6900
Hi, I just test one 60MHz, I have a periodic phase shift.. can you sync the scope on the output at 50KHz for instance ?
Not sure what you mean - do you want to create a periodic phase shift or you're observing it undesirably? There is an issue with sweep mode losing phase lock
No, I mean: if you reset the default settings, chose 50kHz 5Vpp Sine, periodically there is a phase shift, a sine period is not complete, if fall to zero and restart. I received one of the last JDS6600 60Mhz.
Hmmm.. Perhaps you have a dud. I've just tested your 50kHz/5Vpp and it seems okay: imgur.com/a/xgHib. Other frequency/phase tests here: www.eevblog.com/forum/testgear/anybody-know-anything-about-this-signal-generator/
5:44 When you choose on the generator 1Vpp and 50Ohm(fix), you should get on your oscilloscope 1Vpp with a 50Ohm load
and not 0,5Vpp.
Setting: 200mV/div
Not bad for the cash! Back-lighting the enable buttons might be an easy and useful mod too. Annoying it comes up by default with the output turned on! If you get it to make a DC output (or whatever) and put your scope in AC mode while turning down the volts/div can you see much switching noise leaking through?
Ok never mind - saw the post on EEVBlog
can I use ch2, to modulate a signal from ch1? (example: 1MHz carrier on ch1, 1000Hz tone from ch2) or would this possibly fry the outputs if they short together? What is a good way to mix the two signals? I'm a little disappointed in the modulation functions of this model compared to the 6800 or 6900. maybe I should have spent that extra ~$40! :P
Hi. Can this produce an AM wave form? Thanks!
If the Ext In can be used to modulate - maybe use Ch-2 output into Ext In ???
I have a CJDS66. Virtually the same. It doesn't turn off by itself. I wish you could select the load impedance. More findings. If the two channels aren't set to the same frequency, but instead set to a multiple of each other (eg ch1 set to 375Mhz and ch2 set to 750Mhz) you can't control the phase of their offset. And their rising edge don't coincide.
Do I have to have another device to plug into output to create signals with my signal generator?
Ill subscribe if you can answer my question soon.
Will that work for CB radio excuse me misspelled
I don't have this model of waveform generator (I have an mhs2300a), but I am thinking of upgrading, so to get an idea of the functionality of the jds6600, I downloaded and installed the pc software. My main interest is in creating arbitrary waveforms using the editor provided, and it seems to be very nice, easy to learn and highly functional.
Unfortunately, the program has a serious bug that I would consider a dealbreaker for me: After creating a waveform with the editor, and saving to the pc, I find that the file that was created is completely unreadable. That's right, the software cannot read its own files! Unless this problem, and the 20 minute shut down problem mentioned in the video can be solved, I don't think this machine can be considered as a worthwile investment.Even at its very low. price
Hmm, I haven't had a chance to check out the software for it yet (having some issues installing it; keeps breaking & crashing when I open it!), but if what you're saying is true, then that's pretty bad. As for the 20 minute shutdown problem it seems to happen very intermittently now so it may just be a dry joint in the barrel jack or something - still, not great...
I asked the designer to comment about this.
We'll see if he does or not. I won't buy it unless I am sure there are no issues.
Does it do AM FM PM ASk PSK modulation?
I just bought this function generator and the duty cycle feature does not do anything when you change it; it seems to be set at 50% no matter what. Somebody can help me with that or may be it is a defective piece.
Привет! Скажи как получить на экране осциллографа частотные метки в режиме свип теста
my signal/ function generator provide constant output voltage for all frequency range when analyzed through oscilloscope, its fine, but when i connect a load across signal generator its output voltage drop significantly why?
Because the scope input impedance is (usually 1Mohm), and the source impedance (I think), is 50 Ohms. Feeding a load of lower impedance will bring the voltage down...
Notice the source voltage said a value that was about hald of what was seen on the scope, until it was switched to a 50 Ohm feedthrough impedance? Then it was equal to the generator setting (perfect impedance matching at 50 Ohms). This is pretty much a feature of every sig gen I've ever worked on: The source voltage is only seen accurately at the load when source and load are the same impedance.
Google impedance matching for more info.
Yeah you need to match the impedance then you see the correct frequency response by half of the voltage output. If you leave one end open the delay in the cable's reflection may constructively interfere and give you higher values. I think the 60MHz version will by definition drop off -6db because of a lack of samples.
The biggest problem of that kind of devices is unable to provide proper sync signal for oscilloscope while sweeping. Real pain in ass.
my understanding is the difference in the 20mhz and higher models is just that firmware you mention would love make mine 60mhz
Perhaps between some of the models, but I don't think you can get the 60 Mhz only by changing the ST micro firmware. According to the specs, The 50 Mhz and 60 Mhz models have a sample rate of 266MSa/s whereas the other models are 200MSa/s. This means they are probably changing something in the FPGA as well (or perhaps they are simply overclocking it?). Also, there's serious amplitude and DC offset limitations above 30 Mhz (it degrades to 5Vpp, and ±0.25V?) so even if it's possible it's not really worth it.
@@battlecoder yes exactly. My feeltech fy6800 also drops the output voltage by 50% from 10 to 60MHz sine wave. I only used 1Vpp. Altough the sampling rate could sustain up to 100MHz I have no idea why the output level drops that much. Do you? On second thought, at 250 MSamples the Nyquist is at 125 so 60MHz is just at the 6db with 4 points per period. It's like using a 1Gs oscilloscope on 250 Mhz.
@Mike Sienicki yes of course, termination has to be at the end of the cable. The Feel tech 6800 still drops amplitude from 20 to 60 Mhz by half. I believe that this is because of poor sampling and the characteristics of the amplifier (even at low output voltages where a constant gain bandwidth product should provide a higher upper cutoff ).
could this be used to download or record signals, so to make filters to clear up signals for cheap oscilloscopes?
The one thing that REALLY bugs me is the button labelled, "AMPL" that changes the voltage value shown (the 5V appearing after bootup). This is because the value shown on the screen is actually the peak-to-peak value - not the AMPLitude of the sinewave! So in fact the output is 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 annoyingly gives out 5.24Vptp into hiZ when set to 5V @ MHz frequencies = a +4.8% error! This rather makes a nonsense of having voltage resolution settable to 1mV! (This 5.24Vptp value was confirmed correct, by measurements using a new HP54645D, a TDS210 and a Rigol DS1102E. Terminating at the scope input with 50ohm 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!
Another minor problem for me, is not being able to use my Windows 10 PC to run the software supplied by RD to create and control waveforms, The s/w control panels are too big for the screen and are cut off, completely hiding many of the necessary s/w buttons. But this problem is almost certainly due to Win10's inability to properly scale 3rd party software - a well known issue.
In addition, as mentioned by others, the instrument's front panel font also looks a bit strange to my western eyes (too ornate? even a bit "unscientific"!)
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.
The amplitude it correct into a 50 Ohm load. Into a "high" impedance, you get approx twice that.
I have the same one except from Koolertron instead of Junce
Uh, in yours the ICs are not scrubbed! Mine is broken and I really need to know what the broken IC is.
It is the SOIC-8 that the bottom right corner of the FPGA is pointing at. At full resolution I could almost read it!
Amigo o meu quebrou o display você sabe qual é o modelo desse display?
Vc consegue me ajudar o manual veio em inglês do jds 6600 series
I just got this and im well happy with it for what it is.. as far as turn it on and the generator comes Strat on is easy fixed just set the generator to how you want it to start up ie on off 5 hz 3000.00 hz what ever and then just press and hold the ok button until it beeps now when even you turn it on it will start like that
Have you played with any arbitrary waveforms? The pics at Banggood imply it is actually 2049 points (1-2049) haha
got any download tips?
Did you ever find out why the unit would shut down after “10 to 20 min?”
Yeah... it’d be great to know about that! Good question, thank you.
Did you solve the sudden powering off after 20 minutes or so? This is a very big issue when making laboratory tests. Units sometimes need to run for days without rest.
Many thank for this video. Greetings from Berlin, Germany Jörg, DL7UJW
I also bought a signal generator, JDS6600 5mVPP effect is very poor, there is a clear switching power supply noise, more than 20MHz sine wave has a significant jitter, the nominal vertical resolution of 14, in fact, simply can not reach, Because the waveform length is only 2048 points, the highest resolution is only 11-bit resolution, the oscilloscope with 20mV voltage and 100nS time base gear test 5V 10Khz sine wave, you can see the rough rough waveform, and 14bit machine More than a lot of open the machine can see the DA is a simple resistor, which used a multiplier, or second-hand components, with a knife gently scraping the surface to drop the black powder,
You're right about the PSU noise, it is quite high. There are definitely some issues that aren't discussed in this video; I've taken a lot more measurements over on the EEVBLOG forum here: www.eevblog.com/forum/testgear/anybody-know-anything-about-this-signal-generator
For example there is an issue with phase locking when doing a frequency sweep, and some distortion issues at 10MHz at max amplitude -> can continue the discussion in the forum thread.
The ugly font is a chinese chracters font. This product was written in chinese originally and they didn't bother to change the font.
Noooo... they love Times New Roman fonts..... You can spot them from a mile away, and it will look like.... Chinese characters!
I have that same model but the brand is Koolertron
Hello i am learning electronics by myself . Can you advice me how to go on self learniing electronics so that i can design my own circuits . Loved your videos . I learnt a lot jus by watching .
Does this device have Saw Tooth invert wave mode and can you set smaller random frequencies like maybe 6457Hz /Saw Tooth Wave/
50% duty cycle like...you know..like any frequency with any wave..and yeh does this device have saw tooth wave
Nice review, but it might be time to get a new spectrum analyzer. It looks older than the one I used in college.
I wish I had even an old one like that. Right now I just play the audio from 'Contact' where they're looking at the frequency of the alien signal and pretend...
helloo the ic's are sanded??
The ones with the external power supply seem to be better, the one with the internal power supply leaks too much ac to the output. Painful even standing on a dry tile floor with bare feet.
And you know your cheap DMM is accurate how?
Generator of Functions everyone put the generated direct connected in the ociloscope more nobody put or knows how to use the generator in test in the circuit ??????? just showing the generator on the oscilloscope is of no use as this anyone knows how to do
75$ (в наличии) www.olx.ua/obyavlenie/generator-signalov-jds6600-60m-60-mgts-2-kanala-chastotomer-100mgts-IDCGBrN.html
junks instrument?
thats a good company name...
Nice video, Tnx. ‘73 de Va2sib
Seriously? This is made by JunCe (junk?) instraments? LMAO!!!
It is not a lastest one. Maybe it is lastest chinqua.
I have a couple of these and have never had them shut down by themselves.
Perhaps you got a faulty one.
Mine also doesn't clip the waveform with DC offset, it simply lowers the Vpp to keep the waveform from clipping.
Perhaps there are different versions of these.
Great Video mate.
Thanks for Sharing 🙏