- Koolertron Upgraded 15MHz DDS Signal Generator Counter,High Precision Dual-Channel Arbitrary Waveform Function Generator Frequency Meter 200MSa/s (15MHz)

Impressive functionality for this price range. Besides the many normal signal generator signal types and adjustment here are some experiences of note. - If you save to memory 00 that acts as the power-on default (1 review here said this could not remember a power on default but that is inacurate, just set memory 00 and that is the power on and in my case is now 1khz sine and my default turns that darn buzzer OFF! - LOVE the modulation modes and ability to have external modulation input. I ran the 60mhz unit up into ham band 28mhz and put am modulation on the signal from the 'MOD' input AND from internal or from channel 2 feeding the MOD input. - The user interface is not all that bad but when you do have to read the manual (RTFM) the wording can be awkward likely from translation but at least the manual is very complete. Really like all the features and display of what is going on. Really great features for a very fair price.

I'm having a blast just getting to know all the things this signal generator can do! It does all the obvious things -- sine, square, pulse waveforms, etc., and it also is capable of a whole lot more waveforms -- rising/falling sawtooth, triangle, and a bunch of waveforms I'll have fun figuring out what they might be useful for. You can easily adjust the phase between the two outputs, and it has every sort of modulation you can imagine. One useful feature I've discovered is the burst mode, where for example you can output a burst of say 10 cycles of say a 1kHz tone (takes 10ms). I've used this to examine the output of a high power amplifier where I don't want to overstress it. As others have pointed out you can easily adjust the duty cycle of the output, but not with sine or square waves for which only symmetrical output is available. I'm not clear who actually manufactures this device -- it looks like it is available with various labels, but is actually a JDS 8000 manufactured by Hangzhou Junce Instruments. The short manual it comes with is pretty useful but I got a more complete manual online from Hangzhou Junce. I have a couple of complaints. 1 - when you switch it on it doesn't go back to the settings you last used it at, which would be very useful. Instead it reverts to the default setting of 10kHz sine wave at 10v p-p, which would not be good to input into a conventional audio amplifier or preamp, which is what I'm using it for mainly. It has multiple memories where you can store settings, but you have to remember to do that manually each time you turn it on. 2 - the output level is indicated only in peak-to-peak volts, which is useful for many waveforms but not so much for sine waves -- I wish you could switch to other units such as rms volts. 3 -- minor complaint -- the connecting lines for the device use standard BNC connectors to attach to the actual device, but have some pretty crude alligator clips on the other end -- the kind where when you squeeze on the vinyl insulation surrounding the alligator clip it tends to just rotate around rather than open. Not a big deal if you already have some good BNC cables with quality microclips or something similar. 4 -- THD is pretty high -- around 0.3% or so, meaning although this waveform generator is going to be very useful for many things, measuring amplifier THD is not going to be one of them. On the other hand I don't think there are many general purpose waveform generators with very low THD -- you need another source for such a signal.

I’m impressed by the capabilities of this signal generator. Not long ago, a device like this would have been prohibitively expensive. The unit is compact and lightweight yet performs exceptionally well, making it a great addition to any test bench. While I’m very satisfied with its functionality, there are a few design elements that could be refined. The display and menus, although in English, retain some stylistic influences from the original Chinese design. This has no impact on usability but may feel slightly unconventional to some users. Setting the operating frequency is straightforward, though the process is a bit unconventional—you select a specific decimal position and adjust the value with the control knob. One minor inconvenience is that while the unit offers plenty of memory slots for saving operational states, it always starts up with its default settings rather than remembering the last frequency and mode used. It would be much more user-friendly if it resumed the previous operational state upon powering on. That said, these quirks are minor and don’t detract from the unit’s overall performance. While it’s not reference-grade test equipment—understandable at this price point—it is an extremely capable and excellent value for general-purpose use.

I tested pretty extensively, and it's impressively accurate. For the price, the company seems to make the best signal generators you can get by a mile. Controls are smooth and functional, display is fine, and comes with clips. A couple things to note: 1. It's super light. The board inside looks to be the same board used with their portable model: https://amazon.com/Koolertron-Precision-Generator-Dual-channel-Frequency/dp/B07597TJPC/ Works great, but means that the thing slides around on a bench very easily. Hot gluing it down or securing some weight inside it fixes that. 2. As usual, the rated frequency only applies to the sine wave. The biggest difference between this and a higher end piece of kit is that with this, the other (non-sine) forms degrade more / at lower frequencies. So you couldn't use the square wave, for example, as a harmonic generator for driving UHF resonators or the like. But if you want to do that, you'll have more specialized equipment anyway - something like WindFreak's stuff. 3. The max amplitude of 20V only applies up to a frequency of (IIRC) 10MHz - after that it's 10Vpp. Most generators limit to 10V or maybe 15V from the start, so it's nice that this does 20 for much of the range. 4. What really impressed me is that they have the frequencies and impedance as accurate as they do. They clearly tested and calibrated this thing thoroughly. Just a great piece of equipment at a killer price.

Works as good as any more expensive signal generator. Currently using it in all of my junior level electrical engineering classes and labs. I haven't had an issue with it.

This is a great audio generator for the money. It's stable, has a clean output, tons of features and it's really easy to use. The screen is well lit, and it only takes a short time to learn the UI. I work on audio gear, and it's got everything that I need. The stability is good enough for my wow/flutter test, and the multifrequency waveform is perfect to troubleshoot filters. Everything works like it should. The only negative would be the thing is so light, you have to have a hand on top when you push a button or you'll push it off the shelf. Tie it down some way, or just learn to hold it while you use the buttons. I'm very happy with mine.

These units are found from several different sellers, all essentially using the same chipsets, software, but with their own branding. For the $ there is an excellent bang-for-the-buck of these units. I did initially get some customer response but then it simply stopped and my messages were ignored. The issue that prompted me to return is that I could not get the firmware update program to update the firmware: it indicated it couldn't open the port. I knew the port was working as the Windows software when running used that port (I of course didn't try to run both programs at the same time). Also note, over the past few years I've had outstanding customer support from Amazon seller's in general. I only wish I could have had a better customer experince with Koolertron, but that's how it goes. ------Update: To be fair, Koolertron finally contacted me regarding the firmware indicating that the firmware is the latest and doesn't need to be updated. Of course this doesn't address the issue that according to the firmware numbers it indicates there is a newer version and I have this file update and I simply cannot get the firmware update program to work. So, I will still be returning this item and trying another vendor. Still i rate only 3 stars mainly as overall it's a good function generator for the price but there are support issues.

Good value for the money, not for every day use