Measuring high voltage

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Jonatan

Measuring high voltage

Post by Jonatan »

I am building tube-amplifiers for audio use. I want an really exact oscilloscope, because the oscilloscopes that I have used in the past (8 bit, 60- 200 MHz) have not been able to give me the precision I need, and has basically just been a way to visualaize the readings on my bench multimeter.
I looked at the ADC-216, and it lookes like a promesing product, but it can only accept +-20V input. If I use a 100x probe does that mean that I can measure +-2000V? I need to be able to measure voltage up to about 1000V, and I have been able to do this whit an Tektronix oscilloscope and an 100x probe, but whit really bad accruacy. Would the ADC-216 solve my problem?
I am also a bit confused about the relation between; sample rate, buffer size and bandwidth.
If I want to record, say a start-up scenario of about 30 seconds, what will the accuracy be on the recorded material? Why can't I record directly to my harddrive and get all the data points I need?

Another question....
I have seen that you have a function generator that you can link whit one of your oscilloscopes, to generate frequency response curves. Will that work whit the ADC-216 as well? Why do I need to link the function generator whit the oscilloscope? Can't I just measure the input whit probe A, and the output whit probe B, and let the software compute the frequacny responce from the measuments?

Michael
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Post by Michael »

Hello Jonatan,

The ADC216 has a maximum voltage range of ±20V, the ovlerload protection is ±100V. If you use an islolated probe with a x100 ratio, this will give you 10V output max, this would be 0.153uV steps. When you factor the attenuation ratio, the actual voltage steps will be 15mV.

As a further point, a 12bit scope would give you a resolution of 244mV, could you consider a 3224 instrument?

Best regards,
Michael
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Jonatan

Post by Jonatan »

Why would the 3224 be a better choice? It has more bandwidth, but not enough to measure digital signals (I personally think that at least 200 MHz is required for digital measurements), and as far as audio is concerned the ADC16 has enough bandwidth, so what would be the advantage of the 3224 in my application?

Michael
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Post by Michael »

Hello,

The 3224 has the advantage of being USB connected and powered as well as a large buffer and 12bit resolution, it is also £100 less in price.

The ultimate choice is yours, go for what is important to your application.

Best regards,
Michael
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Jonatan

Post by Jonatan »

Maybe my posts have been a bit confusing, so I will try to be a bit more clear.
I am looking for an audio measurement solution, whit high precision and the capability to measure high voltage (1000V p2p).
I would like to make accurate voltage measurements, spectrum analysis, noise evaluation, distortion analysis and be able to get the frequency response of a circuit (i.e. draw bode-plots).
For this I need an oscilloscope, and a function generator and maybe a differential probe. I would like the function generator to be able to be linked whit the oscilloscope, so that the system can generate bode-plots (frequency response curves).
Can you offer me this solution? Can you give me a few options, pointing out the pros and cons?

Best regards, Jonatan

Michael
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Joined: Thu Jul 07, 2005 12:41 pm
Location: St Neots, Cambridgeshire

Post by Michael »

Hello Jonatan,

Our software is not currently capable of performing math functions on the input data. You can export the data to excell or similar to analyse the data.

As for 1000v, a differential input HV probe will be fine as most will accomodate the audio spectrum.

The scope choice, again, is yours. Choose what is important dynamic range or higher bandwidth.

Best regards,
Michael
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Pico Technology
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