UNI-T UTG932E Signal Generator and Upgrading It to the UTG962E

I’d wanted to buy a signal generator for a long time, but kept putting it off. Maybe because I already had a couple of basic models at home, or maybe because I didn’t really need one that badly. But after watching one of the videos, I finally decided to get one. I found the lowest-priced option available at the time, placed the order, received it, and did a few tests. I also upgraded the firmware to the higher-end model’s version.

As usual, a reminder: to keep up with new posts on the blog, I recommend following me on Instagram. I’ll post notifications about new articles there and might also share something interesting from time to time — link to my account

This generator isn’t new, and upgrading the lower-end model to the higher-end one has been known about for a long time, but I thought it might be useful to someone.
I chose the store based on the lowest price available when I ordered. With the discount and coupon, it came to $84.49, which I think is pretty good.

A while later, I picked up a small box from the post office. The instrument was packed neatly, although I think they could have put something soft on top of it, since the encoder knob left an imprint on the top cover.


I’ll start with the specifications. I have the lower-end version; the higher-end one differs in its maximum frequencies in some modes.


What’s included:
1. UTG932E signal generator
2. Manual
3. Power supply
4. Power cable
5. BNC-to-BNC cable
6. BNC-to-alligator-clip cable



The manual is basically just instructions on how to download the proper manual.


1–3. 5 V, 2 A power supply. It comes with two types of detachable plugs. As I understand it, the E at the end of the model number indicates the European version, and the difference is probably the detachable plug for European outlets.
4. Power cable, USB to 5.5 × 2.1 mm
5. BNC-to-BNC cable, marked RG-58
6. BNC-to-alligator-clip cable


And here’s the subject of this review. Unlike the common Chinese signal generators, it has a vertical layout, though that’s probably just a matter of getting used to it. It looks like a digital oscilloscope.


The screen takes up a fairly large part of the front panel, with a row of multifunction buttons below it. Their functions depend on the operating mode.
The screen has a protective film on it. I removed it later because it caused noticeable glare when taking photos. While peeling it off, though, it felt like I was removing the polarizer, so I even held it up to the light to check.


To the right of the screen are the mode control buttons, a numeric keypad for entering values directly, a pair of buttons for enabling the channels and switching between their settings, and the encoder.


1. Two output connectors are on the right side, along with an input that serves as both a signal modulation input and a frequency counter input.
2. On the left are the power switch, a USB port for connecting to a computer, and the power input. One thing to note: the instrument can only be powered through the power connector; USB is for data transfer. That makes sense, since a PC’s USB port is rated for up to 0.5 A, while the instrument draws noticeably more.
3. The back is covered with ventilation holes. They didn’t add so many for nothing: the generator doesn’t get hot during operation, but it does get noticeably warm.
4. It even has a warranty seal, which of course I later cut through :)


Naturally, I had to take it apart, especially since all it takes is removing four screws and gently prying open a couple of clips.
The interior is split into two sections: the front panel with the control board, and the rear section containing the analog circuitry.


The control board is generally laid out neatly, but that chip with its markings rubbed off looks downright bizarre.


Some buttons are backlit with LEDs, while there are also empty spots. I wonder which model they were intended for.
The PCB revision date is also shown here.


Memory and voltage regulators. The second photo shows the EEPROM chip, which I’ll come back to later.


The second board is absolutely packed with components, and the large number of relays immediately catches your eye.


There’s also a DAC chip (if I’ve identified it correctly) and flash memory. Above them you can see a DC-DC converter chip, also with its markings rubbed off. What the heck...


The analog section, along with the relays responsible for switching the voltage ranges.


There’s nothing else interesting inside, so next I’ll briefly cover the software and run some tests.
When powered on, the manufacturer’s logo appears, and a few seconds later the generator enters normal operating mode.


There are two channels, which can be configured and enabled independently. Select a channel to configure by pressing its button; press it again to turn the channel on or off.
It has standard generator modes—sine, square, pulse, noise, and DC—as well as modulation modes: amplitude, phase, frequency, and FSK. In these modes, the signal can be modulated by an input signal.


There are also options for generating complex signals, both prerecorded ones and signals created and added using the software. I couldn’t get the software to work, and didn’t investigate further since I don’t need it for now.
You can also generate a signal with a sweeping frequency by setting the start and end frequencies and the sweep time.
There’s also a frequency counter. I tried it and it works fine, but I don’t have any frequency standards, so I didn’t test it. I’ll just note that the reading updates automatically during measurement. If you disconnect the input, the last value remains on screen for quite a while, which is handy.


1. Channel settings. The useful option here is adjusting the load’s internal resistance from 1 Ω to 999.9 Ω; beyond that, it switches to HighZ mode, meaning no load.
2, 3. General device settings.
4, 5. There’s some kind of help system for the operating modes, but it won’t be useful to everyone since all the tips are in English. It’s easier to read the manual.
6. Device information: firmware version and serial number.


For my first test, I decided to check the simplest thing: voltage output. The instrument can set the output voltage anywhere from 10 mV to 10 V.
1. 10 mV
2, 3. Still 10 mV. I noticed quite a bit of fluctuation, so I checked the min/max readings—and sure enough, the voltage varied between 9.449 and 9.480 mV.
4–9. Tests at 100 mV, as well as 1, 2.5, 5, 7.5, and 10 V. Stability was noticeably better at the higher settings, but accuracy wasn’t. I expected a bit more.


Since the generator runs on 5 V, which can be handy when powering it from a power bank to eliminate a galvanic connection, I was curious about its power consumption. Nothing was connected to the outputs during the test; with a load, consumption would probably be a little higher. Consumption also depends on the output voltage and operating mode, so I tried to choose settings that would show the maximum.
1. Outputs off.
2. One output on.
3. Both outputs on.


The tests were performed using a Rigol DS1054Z oscilloscope. Its specified bandwidth is only 50 MHz, which is a bit low for testing this generator, but it has been unlocked to 100 MHz.


The generator’s screen shows the waveform that will appear at the output on the right, which is handy. It even simulates the signal edges becoming less steep as the frequency increases. For example, in the same mode, the graph on the right will look different at different frequencies. With a square wave, it displays a rectangle at frequencies up to 1 MHz. As you increase the frequency, it starts to look more and more like a trapezoid.


I tested it with the generator's original cable, but while I was at it, I decided to compare it with an oscilloscope probe cable.
First, the generator cable:


And here's the oscilloscope probe cable in 1x and 10x modes. You can see that in 1:1 mode the signal is attenuated a little more; with the attenuator switched on, the trace looks about the same as with the generator's original cable.


Square waves at 1, 10, and 100 kHz, and 1, 10, and 15 MHz.


The signal's rise time doesn't depend on frequency: 1 kHz on the left, 10 MHz on the right.


Sine waves at 1 kHz and 10 MHz.


Sine waves at output voltages of 20 V and 10 V, and 100 mV and 10 mV. You can see that noise is very noticeable at the minimum voltage. It's probably coming from the oscilloscope input; I tried powering the generator from a power bank, but there was no difference.


Complex signals, just as examples. There are plenty more, and you can add your own, too.


Different types of modulation: AM, PM, FM, FSK


Out of curiosity, I tested both channels running at the same time. As I mentioned, the output parameters for each channel can be set completely independently.


By the way, there was a small mix-up here: the probe was set to one mode, while the oscilloscope was still configured for the other. I don't think it matters in this case, though.


The key difference between the UTG932 and UTG962 models is the maximum output frequency in sine, square-wave, and pulse modes. I have the lower-end model, so the maximum frequencies I can get are 30, 15, and 15 MHz, respectively.


But you can unlock the instrument and turn it into the higher-end version.
To do this, you need to desolder the EEPROM chip (shown above) and read its contents.


Then change one value from 3 to 6—it’s highlighted in red—and write the data back to the chip. If you're unsure or worried, you can simply read the original chip, modify the data, and write it to another chip, keeping the original safe in a little box :)
The chip is in an SO-8 package. I didn't have a socket for it, so I had to solder wires to its pins and connect it to the programmer that way.


After reprogramming, I got frequencies of 30, 20, and 20 MHz in the modes mentioned above. I can't say I really needed this, but if it's possible, why not? Of course, doing this voids your warranty and could even break the instrument, so proceed entirely at your own risk.


And here it is in operation.
1, 2. 45 and 60 MHz sine waves.
3, 4. 20 MHz square wave in different modes.


Of course, you might ask what I used before. I have a homemade generator—or rather, not just a generator.
I built it around the mid-1990s, or about 25 years ago, and it still works, by the way.


Inside, it's dark, dusty, and generally a bit depressing. The frequency-setting resistor isn't in the photo. I couldn't find a multiturn one back then, so I used a regular potentiometer plus a vernier dial from a portable TV.
1. Front view
2. Rear view. You can see the frequency counter's “warm, tube-like” digital display, as well as some board in front of it, though I can't remember what it does.
3. Power supply and timing circuit.
4. Analog generator up to 100 kHz, based on a circuit from Radio magazine. I remember looking for bulbs for it; they're in the feedback circuit. The ranges are switched by relays controlled by a rotary switch, and the output voltage can also be switched.
5. The input signal conditioner is visible beneath the frequency counter board.
6. Voltage-to-frequency converter for using the instrument as a voltmeter.

I also planned to add a high-frequency attenuator at the input. I etched the board and almost finished soldering it, but then changed my mind.


Conclusion.
Well, overall, I can say I'm happy with it—especially after managing to turn it into the higher-end version :)
The only strange thing is that the software doesn't detect the instrument. It's not that this has been a major problem for me, but still...

In short, it's more than enough for most applications. If it isn't, then you're a high-level professional, and my review probably isn't much use to you, since you'll need a completely different class of instruments.

That's all for today. I hope you found it useful.