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Max. frequency that can be measured by an Oscilloscope

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cherukukeshav

Junior Member level 3
Hi,

Can any body tell......
How to calculate max. frequency that can be measured by an Oscilloscope with respect to Bandwidth and sampling frequency.

Pls give me some links if possible..

Keshav

see the specification of CRO. SAY 20 MHZ INDICATES THAT IT CAN MEASURE UPTO 2 MHZ ONLY.

A 20MHz scope can easily measure 20MHz.

It depends on the sampling rate and the bandwidth. As per the nyquist criterion, you need to have the sampling rate to be at least twice the frequency of the signal.
So a 2GS/s scope can correctly measure 1GHz signal (sine wave).

........limit posed by amplifier/s inside it (horizontal and vertical deflection section uses it)

dear Keshav,

How to calculate max. frequency that can be measured by an Oscilloscope with respect to Bandwidth and sampling frequency.

Let me state that an oscilloscope is a "time-domain" device. So the term "Bandwidth" is totally out of context. The max freq. is generally printed on the scope itself. 100MHz scope can measure anyhing upto 100MHz precisely.

The exact implemented sampling freq is mentioned in the scope manual. also mentioned is the precise error involved at a given temp.

Sai

ITs easy.. the limit is specified by the manufacturer. If its a iGHz osc, thats the limit... its the max possible limit though..

probe also has an limits measured frequency

Usually the minimum time base value gives you an approximative idea of the maximum frequency

arnarendra said:
It depends on the sampling rate and the bandwidth. As per the nyquist criterion, you need to have the sampling rate to be at least twice the frequency of the signal.
So a 2GS/s scope can correctly measure 1GHz signal (sine wave).

That is what i am not sure about. Many digital scopes just samples signal and when constructing just connect lines on screen from one sample to another.
To correctly display signal of half frequency of input bandwidth scope should digitise signal in quadrature by 2 ADC's .

hi

the maximum frequency is one of the characteristics of your oscilloscope
usually they are written on the front or the back of the apparatus

The time base setting that controls your resolution (sampling) will decide the maximum frequency that you can measure

Thanks to all of u.

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