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selection of oscilloscope

Which product is right for your exact requirements

selection of oscilloscope

Postby keets_17 » Sat Sep 06, 2003 4:43 pm

If I want to measure around 900mhz signal, which model should be selected?
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Postby markspencer » Mon Sep 08, 2003 8:19 am

Hi,

The fastest single shot units that we have can measure 50MHz, these units are ADC212/100 and ADC200/100.

However, if the signal that you want to look at is a repetative one then it would be possible to use the ADC212/100 with ETS triggering. In this made the unit is capable of sampling at 5Gsps.

http://www.picotech.com/pc_oscilloscope.html

Best regards,
Regards,

Mark Spencer
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measuring signals with frequency content above 50Mhz

Postby vicente » Mon Feb 16, 2004 5:09 pm

Hello Mark,
I am a little bit confused about your answer. If the analog bandwidth is only 50MHz how will I reproduce a waveform that has significant energy at 900MHz regardless of how fast the sampling rate is? I am trying to decide which scope to purchase and wonder if the random repetitive sampling feature is worthwhile.
Vince
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Postby markspencer » Tue Feb 17, 2004 9:15 am

Hi,

I am sorry that my previous answer wsa confusing. The 50 MHz is for a single shot signal, where it will be differetn each time.

The second option is the repetative mode, using ETS (Equivalent Time Sampling), since the signal is repetative it can be sampled over a number of times to build the signal up and display it on the screen.

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Mark Spencer
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Postby Guest » Sat Feb 21, 2004 6:36 pm

Hi Mark,

I still don't get it. The datasheet says the ADC212/100 has an analog bandwidth (the front end bandwidth) of only 50MHz. Presumably this means there is some kind of low pass filtering (perhaps due to the frequency response of the front and amplifier?) that will limit the bandwidth of the signal. It seems to me that it does not matter how fast you sample after that point, you won't see much of a signal that is, say, 100MHz, much less 900MHz! Whether you reconstruct a repetive waveform from one or from many cycles should not matter.

What am I missing? Perhaps the analog bandwidth is not 50MHz as the datasheet says? That would be great for my needs!

Vince
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Postby markspencer » Mon Feb 23, 2004 9:14 am

Hi,

The ADC-212/100 can measure 50 MHz in a single shot, this means that if you put a signal above this then you will get alyasing. However, when using ETS mode the software (Picoscope) controls the sampling and uses more than one data capture to construct the signal.

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