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We know OWON as a supplier of excellent oscilloscopes. So we were curious to see how the low-cost function generator DGE1030 from the same brand would pass our tests. Spoiler: with flying colours! |
Introduction to the DGE1030 from OWON
A single-channel function generator
Most function generators offered today have two channels, you can generate two different signals. The usefulness of this escapes our imagination. In fact, we never use this function except to play with it occasionally. When we came across OWON's DGE1030 while surfing, we immediately noticed that this generator has only one output and is a lot cheaper than the competition. The fact that this generator delivers sine waves up to 30 MHz and the fact that we are extremely satisfied with our OWON oscilloscope were the reasons to buy one for a thorough test.
Price and scope of delivery
The DGE1030 was developed by Chinese company Fujian Lilliput Optoelectronics Technology Co and marketed under the brand name OWON. This function generator is offered through well-known Chinese sales channels such as Banggood and numerous vendors on AliExpress at a price of around one hundred euros. At the time of writing this article, the generator costs just € 90.17 at Banggood, but that may be different by the time you read this article, that's how it works these days. At AliExpress, you will pay € 102.26 for it at most sellers.
The generator, well packed in a sturdy box, comes with:
- A 90 cm power cable.
- Two USB-B to USB-A cables of 95 cm.
- A BNC to crocodile cable of 100 cm.
- A USB mains plug power supply providing 5 Vdc at 2 A.
- An excellent 14 page 'quick start' English manual
Why two USB-B to USB-A cables are included is a mystery to us.
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| The scope of delivery of the DGE1030. (© Banggood) |
The appearance of the DGE1030
In the picture below, we have summarised the three views of this surprisingly small device. Indeed, the front panel measures only 19.5 cm by 8.0 cm and its greatest depth is only 6.5 cm. The DGE1030 weighs 388 grams. There is a USB-B connector on the back that allows you to connect the device to a PC. However, that only makes sense if you plan to design your own signal shapes and store them in the generator's memory.
You will also see a standard 2.1 mm x 5.5 mm power connector, to which you should connect the power supply. Indeed, the DGE1030 has no mains supply but is powered from a standard supply voltage of 5.0 Vdc. A trend we are finding more and more often in Chinese measuring equipment, which we warmly welcome. You can power the DGE1030 from a 5 Vdc power pack, which is useful in some applications as it eliminates all kinds of problems that can arise from capacitive and inductive coupling to and from the mains.
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| The appearance of the DGE1030. (© 2024 Jos Verstraten) |
Operation of the device
There are 29 push buttons and one rotary knob on the front panel. Despite the device's small size, these buttons are easy to operate. However, you have to hold the housing with your left hand while pressing the buttons with your right.
- The six white buttons below the display:
These select the shape of the output signal. You can set sine, rectangle, triangle, pulse, noise or arbitrary. The latter option gives you a choice of no less than 153 arbitrary shaped waveforms. In addition, you can also store 16 self-defined waveforms in memory and select them with this button. - The five grey buttons to the right of the display:
These buttons select one of the waveform's parameters such as frequency, amplitude, offset, phase, highest value or lowest value. When entering the value of the parameter, you can use these buttons to select the unit, such as MHz, kHz, Hz, mV or V. - White rotary knob:
Allows you to subsequently set one digit of the numerical value of that parameter. Pressing this button corresponds to 'OK' or 'Enter'. - Blue cursor buttons:
Selects the digit you can set with the rotary knob. - Twelve white push buttons:
Alternative way of setting the value of a parameter. After keying in one of those buttons, the 'Set Value' window appears on the screen and you see what value you enter with the keypad. You have to confirm by selecting the unit with the light-grey buttons. - Grey 'Utility' button:
Enters the 'Utility' menu where you set various general properties of the unit. - Grey 'Mode' button:
Selects between unmodulated output or modulated output. You can choose between sweep, burst, AM, FM, PM or FSK. - Yellow 'On/Off' button:
Does or does not put the signal on the BNC output. This button is illuminated in the 'On' state.
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| The control buttons on the front panel. (© Banggood) |
The display
The display is 78 mm by 44 mm in size and provides at a glance all information about the signal delivered by the generator. In the display below, for example, you can see that the generator is set to a linear sweep with a start frequency of 100 Hz and a stop frequency of 1 kHz. The sweep time is one second, the signal is a sine wave with a symmetrical peak-to-peak value of 6.752 V. What else would you like to know?
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| The display of the DGE1030 in sweep mode. (© Fujian Lilliput Optoelectronics) |
The manual
In addition to the 'quick start' manual provided, OWON has produced a more comprehensive (48-page) manual, which you can download from our account at 'archive.org' using the link below:
General specifications of the DGE1030
According to the manufacturer, this device has the following general specifications:
- Display: 3.6-inch LCD display, 480 x 272 pixels, 65,536 colours
- Power supply: 5 Vdc ~ 2 A
- Dimensions: 19.5 cm x 8.0 cm x 6.5 cm
- Weight: 388 g
- Communication with PC: USB
- DAC resolution: 14 bit
- Period length: 8,192 samples max.
- Sampling rate: 125 Msa/s max.
- Analogue bandwidth: 30 MHz
- Resolution frequency setting: 7 digits
- Frequency stability: ±30 ppm (-40 °C ~ +40 °C)
- Resolution amplitude setting: 4 digits
- Amplitude setting accuracy: ±1 %
- Offset setting: ±10 V (<10 MHz), ±4 V (>10 MHz)
- Offset resolution: 4 digits
- Offset accuracy: ±1 %
- Output voltage: 2 mVpeak-to-peak ~ 20 Vpeak-to-peak (<10 MHz)
- Output voltage: 2 mVpeak-to-peak ~ 8 Vpeak-to-peak (>10 MHz)
- Output impedance: 50 Ω
Sine wave specifications
- Frequency: 1 μHz ~ 30 MHz
- Bandwidth: ±0.5 dB up to 30 MHz (1 Vpeak-to-peak)
- Harmonic distortion: <0.2 % (10 Hz ~ 20 kHz, 1 Vpeak-to-peak)
Rectangle waveform specifications
- Frequency: 1 μHz ~ 15 MHz
- Rise and fall time: <20 ns
- Jitter: 200 ps + 30 ppm (1 Vpeak-to-peak)
Pulse waveform specifications
- Frequency: 1 μHz ~ 15 MHz
- Duty-cycle: 0.40 % ~ 99.60 %
- Rise time: adjustable, range depends on frequency and duty-cycle
- Fall time: adjustable, range depends on frequency and duty-cycle
- Overshoot: <5 %
Triangle waveform specifications
- Frequency: 1 μHz ~ 1 MHz
- Linearity: < 1 % ( 1 kHz, 1 Vpeak-to-peak)
- Symmetry: 0 % ~ 100 %
Noise waveform specifications
- Bandwidth: 20 MHz
- Type: Gaussian white noise
Arbitrary waveform specifications
- Frequency: 1 μHz ~ 10 MHz
- Number of built-in waveforms: 153
- Number of self-defined waveforms: 16
The interior of the DGE1030
Opening the housing
The dark grey back of the case is attached to the light grey front with five screws. Three are clearly visible at the top, two are behind the removable feet at the bottom.
The main PCB
The main PCB, see the picture below, fills the entire enclosure of the generator. The left half of the PCB, up to the connector for the ribbon cable going to the USB board on the back, is shielded with a solid sheet of aluminium. Only for the six miniature relays and an electrolytic capacitor are cutouts in this shielding plate.
The large square chip is an EG4X20BG256. That is OWON's favourite FPGA used in various measuring devices from this manufacturer. Several chips are unreadable. What we can find out though:
- 2 x MS9714:
This is a fast 14 bit wide DAC from Hangzhou Ruimeng Technology Co.,Ltd with a maximum sampling rate of 125 MSa/s and rise and fall time of 2.5 ns. - THS3096:
A dual and very fast current-feedback op-amp from Texas Instruments with a bandwidth of 145 MHz and a slew rate of 5,700 V/μs. - RS8412:
A dual standard op-amp from Jiangsu RUNIC Technology Co., Ltd.
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The main PCB of the DGE1030. (© 2024 Jos Verstraten) |
Trace Length Matching
On the PCB, you can discover a nice example of 'Trace Length Matching'. This technique is used to compensate runtime differences on a PCB so that signals passing through different traces arrive at their destination simultaneously. This is applied when connecting the FPGA to the two very fast DACs. By adding extra meanders in the traces, the running times of the various signals through the traces are equalised. The advantage is that the chance of 'glitches' occurring on the analogue output voltage is much reduced because it is ensured that all bits of the DACs change value at the same time.
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Run time difference compensation with 'Trace Length Matching'. (© 2024 Jos Verstraten) |
A second PCB below the first one
No microcontroller can be detected on the PCB. This is obviously not possible and a closer look at the construction reveals that there is a second, equally large PCB underneath the one shown in the previous photos. Carefully unscrewing and folding the top PCB reveals this lower PCB, as well as the back of the top PCB where we spot an F1C200S microcontroller. This is a popular processor from Allwinner Technology, mainly used in fast graphics applications. It is based on the ARM9 architecture and operates on a 24 MHz clock.
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| The PCB combination in the DGE1030. (© 2024 Jos Verstraten) |
Working with OWON's DGE1030
Setting the sine, rectangle and sawtooth waveform
Thanks to the data in the display, you can easily set the parameters of these signals. The screen dump below shows how this is done for a sine waveform. The right-hand part of the display shows the functions of the five light-grey buttons. The top button allows you to set either the frequency or the period of the signal. The selected option is shown in a white frame. The light blue frame around the words 'Frequency' and 'Period' indicates that you last operated this pushbutton and that you can set the value of this parameter using the rotary knob or the keyboard. You can set the voltage values of the sine using either the 'Amplitude / Offset' combination or the 'High Level / Low Level' combination. What the 'Phase' button does is unclear. This is a familiar concept in function generators with two outputs. Then you can set a phase difference between the two signals. But here there is only one signal and there is also no additional output on which a phase-shifted signal can appear to trigger your oscilloscope. The comprehensive manual does not answer this either.
All set values appear below the oscillogram on the display. It can hardly get any clearer than the DGE1030 does!
For the waveform triangle, the bottom pushbutton is given the 'Symmetry' function. You can set this parameter between 0 % and 100 %, so you can also generate rising and falling sawtooth waveforms.
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| Setting the sine, rectangle and sawtooth waveforms. (© 2024 Jos Verstraten) |
Setting the pulse waveform
There is something special about this! The bottom push button now gets the 'NextPage' function and on that next screen you can set not only the duty-cycle but also the rise and fall times of the pulse individually! A never before encountered option in low-cost function generators! The setting range of the rise and fall times obviously depends on the frequency and duty-cycle.
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| A pulse with individually set rise and fall times. (© 2024 Jos Verstraten) |
Setting the noise waveform
With this waveform, you can only set the maximum peak-to-peak value of the signal using the 'Amplitude / Offset' combination or the 'High Level / Low Level' combination. The DGE1030 provides a Gaussian white noise with a fixed bandwidth of 20 MHz.
Setting the arbitrary waveform
The first page gives the settings for frequency, amplitude and phase in the same way as for the sine waveform output. On the second page, you can choose between 'Built-in' and 'Store'. The first option lets you choose from 153 arbitrary waveforms stored in memory. You can immediately see the shape of the signal on the oscillogram on the display. Those 153 waveforms are in nine groups:
- Common (14 pieces)
- Medical treatment (10 pieces)
- Standard (11 pieces)
- Maths (29 pieces)
- Trigonometric functions (43 pieces)
- Window functions (16 pieces)
- Engineering Window (24 pieces)
- Segment modulation (5 pieces)
- Fan test (1 piece)
You select one of the groups with the light-grey buttons on two pages. Afterwards, you select one of the signals with the rotary knob and a press on the top light-grey button that now represents 'OK'.
The 'Store' option gives you access to up to sixteen self-defined waveforms that you have designed via downloadable software on your PC and stored in the memory of your DGE1030 via a USB connection.
The picture below shows the arbitrary signal shape 'AttALT' from the 'Common' group as an example. This waveform is also called the 'Attenuation oscillation curve'. This signal is used in scientific experiments to simulate mechanical pendulums, the response of a construction to the impact of a heavy object or the fading oscillations in LC circuits. Whether you can come up with useful applications for all those signals in your environment is, of course, an entirely different matter. The vast majority you will undoubtedly never use.
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| The arbitrary waveform 'AttALT' from the group 'Common'. (© 2024 Jos Verstraten) |
Setting modulations
A modulated signal basically consists of two signals: the carrier wave and the modulator. You must first set the signal shape, amplitude and frequency of the carrier wave in the way already described. Usually, you choose a sine wave shape for the carrier wave. Afterwards, you switch to the modulated output signals by briefly pressing the 'Mode' button. The five light-grey buttons give access to the modulations listed below:
- Sweep
- Burst
- AM (amplitude modulation)
- FM (frequency modulation)
- PM (phase modulation)
- FSK (frequency shift keying)
Basically, little changes in the way you need to define the modulator's parameters. The only difference is that in the on-screen oscillogram, you see not only the yellow output signal, but also the red modulator.
Example 1: AM modulation
In the screen dump below, AM modulation is selected as an example. The carrier is set to 2 kHz sine, the modulator to 100 Hz sine and the modulation depth to 100 %.
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| The display during AM modulation. (© 2024 Jos Verstraten) |
What the output signal of the DGE1030 really looks like at this setting is shown on the oscillogram below.
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| The real output signal at the settings of the previous figure. (© 2024 Jos Verstraten) |
Example 2: Burst modulation
In the context of function generators, this word means that the device puts an adjustable number of periods of the signal on the output and then suppresses it for a number of periods afterwards.
In the case of the DGE1030, you can set this by first selecting a burst period and then setting how many periods of the signal in each burst period should be passed to the output. The oscillogram below shows an example of the output voltage of the DGE1030 in this mode.
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| An example of burst generation. (© 2024 Jos Verstraten) |
The 'Utility' menu
Pressing the 'Utility' button puts a menu on the display with three options:
- Display
- Channel Set
- System
The 'Display' submenu
Has three options:
- Backlight:
Sets the intensity of the display. - ScrSaver:
Sets the standby time between 1 and 999 minutes. After this time elapses, the display dims to save energy. Pressing any key reactivates the device. - Separator:
Sets how the device displays the numbers on the display:
1.000,000,000
1.000 000 000
1.000000000
The 'Channel Set' submenu
This tells the software whether you connect the generator to a load with a very high input resistance or to a load with a low input resistance. Since the generator itself has an output impedance of 50 Ω, in the latter case, part of the generated voltage will fall over that 50 Ω and the amplidude indication on the display is no longer correct. You can set the value of the load's input resistance between 1 Ω and 10 kΩ. The software then calculates the real value of the output voltage and automatically adjusts the value on the display. The set value of the load resistance is shown on the display.
The 'System' submenu
This submenu has the following options:
- Language:
Sets the language of the messages on the display. - Beeper:
Whether or not to beep when operating the keys. - USB Dev:
Selects the communication protocol of the USB link. - Factory Set:
All factory settings are restored. - Upgrade:
Downloading a new version of the firmware via your PC.
Testing OWON's DGE1030
Sine waveform distortion
The manufacturer claims a total harmonic distortion of less than 0.2 % between 10 Hz and 20 kHz at 1 Vpeak-to-peak output voltage. This is an excellent value, due to the 14 bit resolution of the DAC. Our specimen meets this specification. At 1 kHz, we measure a total harmonic distortion of only 0.15 % with our distortion meter 331A from Hewlett Packard.
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| The harmonic distortion at 1 kHz. (© 2024 Jos Verstraten) |
Sine waveform bandwidth
According to the specs, the bandwidth of the DGE1030 is ±0.5 dB up to 30 MHz at 1 Vpeak-to-peak. This means that the signal attenuation at 30 MHz would be only a factor 0.94 compared to the signal at 1 kHz. An extraordinarily good specification which, of course, we test. We first measured the sine wave signal with our oscilloscope at 1 kHz and set the horizontal cursors to the peaks of this signal. Afterwards, we increased the frequency to 10 MHz and 30 MHz, obviously without moving the cursors. You can see the results in the oscillograms below. We measured at 8 Vpeak-to-peak and with a properly calibrated 1/10 probe. Our specimen does even better than ±0.5 dB and appears to deliver an identical amplutude up to the maximum frequency.
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| Comparison of signal amplitude at 1 kHz, 10 MHz and 30 MHz. (© 2024 Jos Verstraten) |
Quality of a 1 kHz ~ 10 mV sine wave signal
Quality of a 1 MHz square wave signal
Measuring the rise time of the square wave signal
In many cheap function generators, the quality of very small signals is lousy. There is a lot of interference signals on the output voltage. This is due to poor shielding, careless PCB design, cheap DACs and a poorly interference suppression of the switched-mode power supply. With the DGE1030, there is absolutely none of this. The oscillogram below shows the output signal when set to 1 kHz ~ 10 mV sine wave signal. We should note, however, that in this test the function generator was powered from a 5 Vdc power pack and was therefore completely separated from the 230 V mains.
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Quality of a 1 kHz ~ 10 mV sine wave signal. (© 2024 Jos Verstraten) |
Quality of a 1 MHz square wave signal
In the oscillogram below, we compare the quality of a 1 MHz square wave generated with the DGE1030 (yellow trace) with that provided by the well-known 'fast edge pulse generator' PCB (blue trace) that provides a square wave signal with a rise time of only 180 ps. Again we measure with a compensated 1/10 probe, the 'fast edge pulse generator' PCB is plugged directly into the BNC input of the oscilloscope.
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| Quality of a 1 MHz square wave. (© 2024 Jos Verstraten) |
Measuring the rise time of the square wave signal
According to the specifications, the rise time of the square wave signal is less than 20 ns. Of course, we are going to test that! We connect the output of the DGE1030 via a BNC cable to one of the inputs of our oscilloscope which is terminated with a 50 Ω terminator. The horizontal cursors are set to 10 % and 90 % of the amplitude of the signal. The vertical cursors are set to the intersections of the signal and the horizontal cursors. The oscilloscope calculates the rise time of the pulse as 17.80 ns. So the GDE1030 again meets the specifications.
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Measuring the rise time of the square wave signal. (© 2024 Jos Verstraten) |
The linearity of the DAC
A triangular signal is ideal for testing the linearity of the DAC. Indeed, the shape of such a signal must be perfectly straight and free of irregularities such as glitches, double lobe glitches and non-monotonic errors.
Glitches occur because not all electronic switches in the DAC switch from one state to another at the same speed. This is manifested by a small non-linearity in the output voltage. However, it is also possible that all switches have to toggle. Then a hefty interference pulse called a 'double lobe glitch' may occur.
For this test, we generated a triangular voltage with a frequency of 1 kHz and a peak-to-peak value of 5 V. We increased both the sensitivity and the time base of the oscilloscope considerably, so that any inaccuracy on the shape of the signal is visible on the screen. In the oscillogram below, you can see that in this respect too, the DGE1030 meets all your needs. Apart from some digital noise in the mV range, no irregularities can be detected on the shape of the triangle.
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| Measuring the linearity of the DAC. (© 2024 Jos Verstraten) |
Accuracy of sine wave signal voltage indication
Finally, we measured how accurately the Vrms of the sine wave voltage is shown on the display. We measured with a 1 kHz sine wave voltage and checked the rms value with our ET3255 multimeter. The results are summarised in the table below. Below 50 mV, a rather large deviation is present; above this value, the DGE1030 meets its specifications.
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| Accuracy of the Vrms indication of the sine wave signal. (© 2024 Jos Verstraten) |
Our opinion of OWON's DGE1030
In the introductio of this article, we wrote 'Spoiler: with flying colours!'. We assume few readers of this article can be found who disagree with this verdict. The GDE1030 lives up to its specifications and is a wonderful function generator with an excellent price/performance ratio.
We have never found the combination of options listed below on a function generator in this price range:
- Reconstruction of signals from up to 8,192 words of 14 bit.
- Sine voltage adjustable from 2 mVrms.
- Sine voltage up to 30 MHz without measurable attenuation.
- Distortion on sine less than 0.2 %.
- Rise time square wave smaller than 20 ns.
- Rise and fall times of pulses separately adjustable.
- Power supply from any 5 Vdc source.
We can unreservedly recommend this device to any electronics hobbyist who wants to buy a versatile signal source for not too much money.
In fact, we only miss one thing, and that is fold-out legs on the front that would allow you to place the device on the table at a better reading angle.
DGE1030 function generator
