how to measure the noise of power supply?

[xuexucheng]

noise of power supply especially high frequency can affect the noise performance of the circuit, Ritht?
then
how to measure the noise of power supply?
using what equipment?

 

[leo_o2]

Agilent multi-meter can measure noise directly if the noise>0.5mV. Pls use AC setting.
If the noise is too small, you need some amplifier equipment from Tek.

 

[xuexucheng]

If the noise is too small, you need some amplifier equipment from Tek.
Could you explain in detail?
thank you!

 

[biff44]

load it with the full expected load, then AC couple the ripple into an Oscilloscope.

 

[xuexucheng]

noise is often very small.
can the Oscilloscope measure so small noise?
I think it can not

 

[biff44]

Sure. If not, use a low noise op amp with a gain of 100 in front of it.

Most power supplies put out noise in the 10 mv pk-pk or higher range. Pretty easily seen on a decent scope.

 

[allanvv]

Measuring noise is best done with a 1x probe instead of using a 10:1 divider probe. Also your method of probing itself might add "noise" to the signal due to inductance of the ground lead.

 

[leo_o2]

Pls check it with Tek company (the oscilloscope company). I forgot the equipment name. It can amplifier AC noise and connect to Tek oscilloscope. Scope will display the noise.

If the noise is too small, you need some amplify equipment from Tek.
Could you explain in detail?
thank you!

 

[royal12461]

Agilest power meters operate with sensors, which covering numerous frequency and power ranges that connecting RF and microwave signals. Mobile, telephone, and many more like the examples of it.