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Amplify AWG signal

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Amplify AWG signal

Postby Karl Fischer » Wed Jun 07, 2017 7:53 pm

I recently bought the 2205A scope. It works fine but I bumped into a limitation of the AWG. The output voltage range is ±2V. For my application i need a square wave of a least ±50V. Can you recommend additional hardware or suggest electronic circuits how to amplify the square signal from the AWG?
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Re: Amplify AWG signal

Postby bennog » Fri Jun 09, 2017 6:13 am

If the frequency stay below 20kHz then you can use a regular audio amplifier.
If you want even higher voltages you can use a tube audio amplifier :D

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Re: Amplify AWG signal

Postby Karl Fischer » Sat Jun 10, 2017 1:26 pm

Thank you bennog for your reply.

I tried your suggestion with a standard audio amplifier to see how it would perform. It did not do well. Even at low frequencies (<1kHz) the square waves lose their sharp edges and become distorted sine waves. Tube amplifiers might be more suitable but the cost and that they are not "success garanteed" made me decide to look for other alternatives first.

I came across the possibility of using MOSFETS to switch DC voltages to square waves. Is it possible to use the AWG to trigger the MOSFETS? Could you (or someone else) help me with the circuitry? I don't want to blow up my AWG.
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Re: Amplify AWG signal

Postby bennog » Sun Jun 11, 2017 8:10 am

Be aware that a square wave of 1 kHz has higher harmonics running into several hundreds of kHz even MHz.
So that is why you lose the flanks on a audio amplifier.
I you want to make a square wave of 60V or something then i would suggest using mossfets.

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Re: Amplify AWG signal

Postby bennog » Sun Jun 11, 2017 4:14 pm

Do you only want to use it for square waves, e.g. on off ?
If so it will make things a lot easier.

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Re: Amplify AWG signal

Postby Karl Fischer » Sun Jun 11, 2017 6:32 pm

Yes, only for square waves: -on off +on. (Voltage set by DC-PSU) Let's keep it as simple as possible.
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Re: Amplify AWG signal

Postby Karl Fischer » Thu Jun 22, 2017 8:15 pm

After some online research I found that I need a MOSFET+driver but the circuitry is still unclear. I might skip de AWG and use an Arduino + two MOSFET driver modules. I will have to write the code for the waveforms but it's a lot cheaper than amplifying the AWG: flcelectronics.com/a600.html ($5.000+)
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Re: Amplify AWG signal

Postby packo » Wed Aug 09, 2017 10:03 pm

You could perhaps try with the Aim-TTI WA301 (DC to 1MHz bandwidth, up to 30Vpp)
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Re: Amplify AWG signal

Postby lab!fyi » Wed Aug 30, 2017 5:25 pm

packo wrote:You could perhaps try with the Aim-TTI WA301 (DC to 1MHz bandwidth, up to 30Vpp)


+1 I have one, excellent companion to Pico up to 1MHz AWGs.
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Re: Amplify AWG signal

Postby kenedy » Wed Oct 11, 2017 9:48 pm

I am totally agree with bennog's comment and I support his idea.Feel free to follow him.
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Re: Amplify AWG signal

Postby bennog » Thu Mar 15, 2018 4:22 pm

A copule of weeks back I found this https://www.dmcinfo.com/latest-thinking/blog/id/9462/low-cost-function-generator-amplifier-diy

I bought the unit from https://nl.aliexpress.com/item/OPA541-module-power-amplifier-audio-amplifier-5A-current-high-voltage-high-current-power-amplifier-board-free/32816340199.html

Arrived today, looks like most modifications mentioned in the first link are already done on this board.

I am gonna test it tonight to see if it was worth the money.

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Re: Amplify AWG signal

Postby bennog » Fri Mar 16, 2018 4:55 pm

Attached some screenshots of the output.
Default amplification (without modification) is 30 times.
There is no DC decoupling, so if you supply a signal 0 to 1 V, the output will be between 0 and 30V
And if you supply a signal between -1 and 1V the output is between -30 an 30V

There is about a 2V drop-off from the supply voltage.

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Attachments
t7 1300mv square 10kHz.png
t5 1300mv square 1000hz 44V p-p output.png
t4 610mv square + 300mv 1000hz.png
t3 610mv-pp +400mv 1000hz sin in vs out clamp power rail.png
t2 610mv-pp +300mv 1000hz sin in vs out.png
t1 610mv-pp -300mv 1000hz sin in vs out.png
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