Re: Power Meter
Hi all,toggle quoted messageShow quoted text
i think using a scope is not a good solution at all. Measuring a voltage with an oscilloscope is a good idea. Provided you know the subtleties of this device. An oscilloscope becomes very quickly false, even very false in the measurement of a voltage. Look at this excerpt from an article published by Yokogawa, and this is true for all the scopes:
"The analogue bandwidth is defined as the frequency at which the amplitude measured by the oscilloscope has reduced by 3dB (-3dB point). This is approximately 70.9% of the actual signal amplitude (Figure 1). This means, for example, if a 200MHz pure sine wave with 10 Volts peak to peak is measured with an oscilloscope with a bandwidth of 200MHz, the amplitude of the displayed signal will be approximately 7 Volts peak to peak."
So, if you want to calibrate your wattmeter based on an AD8307 with an oscilloscope on 430MHz, you will have to find a very, very expensive oscilloscope !!!! Look rather on the side of the references of power, to realize yourself, it will be much more precise.
73... Philippe - F4GRT
Message du 08/05/18 00:19