Utility
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On this post I'd like to explore the "Utility" interface and function.
First, let's review the Owon specs and some of Owon's instructions verbatim from the manual:
Phase Deviation 0 - 360°
External Reference Clock Input
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Impedance 1 k ohm, AC coupled
Requested Input voltage swing 100 mVp-p to 5 Vp-p
locking range 20 MHz ± 35 kHz
External Reference Clock Output
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Impedance 50 k ohm, AC coupled
Amplitude 5 Vp-p, access 50 ohm
Some of the instructions from the manual (here I only listed what I though may not be obvious)
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To Set the Output Load
For either of CH1 Output and CH2 Output on the Front panel, the Generator has a built-in 50Oseries impendence. If the actual load does not match the set one, the displayed amplitude and offset are incorrect. This function is used to match the displayed voltage with the expected one.
The default settings of the system are as follows:
Output Default
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Function Sine Wave
Frequency 1 kHz
Amplitude/Offset 1 Vp-p / 0 Vdc
Waveforms Default
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Frequency 1 kHz
Amplitude 1 Vp-p
Offset 0 Vdc
Duty Cycle of Square 50%
Symmetry of Ramp 50%
Pulse Width of Pulse 200 us
Duty Cycle of Pulse 20%
Modulation Default
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Carrier 1 kHz Sine Wave
Modulating 100 Hz Sine Wave
AM Depth 100%
FM Deviation 100 Hz
PM Phase Deviation 0°
FSK Hop Frequency 100 Hz
FSK Frequency 100 Hz
Source Internal
Sweep Default
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Start/Stop Frequency 100 Hz/1 kHz
Time 1 sec
Mode Linear
Burst Default
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Frequency 1 kHz
Count 1 Cycle
Period 1 sec
Phase 0°
Others Default
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Brightness 95%
Separator Comma
Screen Saver time 100 minutes
Load High Z
Phase Deviation 0°
Clock Source Internal
Channel Output Control Off
To Set the Clock Source
The waveform generator provides an internal clock source and also accepts external clock source input from the [Ref Clk/Counter In] connector at the rear panel. It can also output a clock source from the [Ref Clk Out] connector for other device to use.
Note: The amplitude of the [Ref Clk/Counter In] input signal must be over 1 V.
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With the above in mind let's first review the "Utility" interface. The basic settings and connections are the same as used in previous posts. Other settings can be read from the AG1012F & SDS7102 images.
Attachment #1 - This is the main Utility menu, there are 4 choices and we have already covered the Counter on a previous post.
Attachment #2 - These are the Display setup choices. 95% is the brightness default and I haven't found a reason to use a different setting. Note that some of the possible settings cause the DC/DC converter associated with this feature to emit an annoying noise.
The default for separator is comma, or you can choose space or nothing (off). I prefer nothing. By default the screen saver pops up after 100 minutes of inactivity. I have no use for that feature either, so I turned it off.
Attachment #3 - These are the Output setup choices. Here you set the load for either channel, set the phase deviation if desired, and set the baud rate. Note that BaudRate is not used on current units, it appears that Owon did use a serial port on early units.
You can enter a load from 1 to 10k ohms or choose High Z by pressing the button. This will just change the button label and hide the load value in the center of the screen as shown in attachment #4.
Note that the generator always uses a 50 ohm series impedance regardless of the setting. It uses the user's input to predict the output voltage based on a potential divider calculation. For example, if you tell it that the load is 50 ohms and that the waveform amplitude should be 2Vpp, the generator will output 4Vpp. This is because it expects that by applying 4Vpp across two 50 ohm resistors in series the voltage across the load will be half of 4Vpp (2Vpp). On the other hand, if you tell it that the load is High Z, then the generator will output 2Vpp. The reason is that in this case the generator expects the load to be greater than 10k ohms, and therefore, the voltage drop across its internal 50 ohm resistor should be negligible. So nearly the full 2Vpp should appear across the load.
Attachment #4 - This is the way the screen appears when the load is set to High Z.
Attachment #5 - Here you can set the PhaseDEv between the two channels to any value between 0 - 360° or turn the feature off by pressing the button. In that case the screen appears as in attachment #6. The default PhaseDev value is 0°.
I would have expected that when the phase is set to 0° or turned off the signals at the output of the two channels, specially if identical, would be in phase. However, this isn't always the case. They are in phase at low frequencies, but as the frequency increases the phase deviation between them also increases. I suspect that this will probably vary between units due to component tolerances. Attachment #7 & #8 show the phase deviation between the two channels at 1kHz and 10Mhz when the PhaseDev is either off or set to 0°.
Attachment #6 - This is the way the utility screen appears when the PhaseDev is set to off.
Attachment #7 - This shows the DSO image of the CH1 & CH2 signals when the AG1012F outputs are set to standard sine wave at 1kHz.
Attachment #8 - This shows the DSO image of the CH1 & CH2 signals when the AG1012F outputs are set to standard sine wave at 10MHz.
Attachment #9 - This shows the utility screen PhaseDev setting required to correct the CH1 & CH2 phase deviation depicted on #8.
Attachment #10 - This shows the DSO image of the CH1 & CH2 signals after changing the AG1012F setting as shown on #9.
Attachment #11 - This is page 1 of the System setup choices. Here you can select English or Chinese, whether you want to retain the last setup choices the next time you power on or just go back to default values, and there is also a button to go back to default values on demand.
Attachment #12 - This is page 2 of the System setup choices. Here you can able or disable beeps that among other things are supposed to wake you when you thoughtlessly ask the unit to do thing outside of its capabilities. I don't get enough sleep as it is, so this is one feature I wouldn't miss if it was forever silenced.
Attachment #13 - This is what you get if you press "Sys info".
Attachment #14 - This is what you get if you try to change the clock source to external but don't have, according to Owon, a suitable clock signal connected to the "Ref Clk/Counter In" connector at the rear panel.
I don't have another signal generator that provides a 20MHz clock at the amplitude level that Owon requires. So to test this feature I looped the "Ref Clk Out" to the "Ref Clk/Counter In" at the rear of the unit. You would think that the clock Owon provides for other generators to synchronize on would also be appropriate for their own generators. So the next two attachments show how this turned out.
Attachment #15 - This shows the DSO image of the "Ref Clk Out" on Ch1 and an AG1012F output set to standard sine at 10MHz on Ch2. The DSO is triggered on Ch2 and the persistence is set to 5 seconds to catch any mis-synchronization between the two signals. When this image was captured the "Ref Clk Out" was looped to the "Ref Clk/Counter In" at the rear of the unit but the clock source was set to "internal".
Attachment #16 - This is the same as #15 but in this case the clock source is set to "external".
Not that I think I'll be using this feature much, if ever, but nevertheless I'm not impressed! I sort of expected this to work flawlessly!
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I think this is it as far as the features available via the unit's user interface!
Unless I remember or one of you remind me of something I missed! Otherwise, I think I'll be turning my attention to the PC software, mainly, Ultrawave.