Purpose of Ferrite Bead in Ground isolation

[Chandra214]

Hi,
please let me know the purpose of having a ferrite bead isolation for ground (between digital and power)?
as far as i understand. the ferrites will be helpful in case of power noise filtering.
And noise from digital line return path wouldn,t affect the power levels as it might do for analog ground(return path).
will the noise from a push button switch within digital circuitry affect my power Ground?
will that have frequency? (even though noise)
does "selecting a ferrite bead" carry any meaning for this?

 

[NoTime]

The filters work in both directions, but have no real effect at the 60hz power line frequencies.
Line filters keep high frequency noise (like RF transmitters) from getting into the equipment and causing unwanted operation.
They also keep high frequency noise from getting out of the equipment, causing it to fail to meet (in the US) FCC part 15 rules.

No idea of what you are asking on the "selecting" question.

 

[zeitghost]

Since different ferrites have different properties, I suppose you select the correct ferrite for the job in hand.

 

[Chandra214]

Does a Ferrite have particular frequency response? Say a 200E Ferrite and a 120E ferrite, do they have frequency characteristics?
i want to isolate my Analog ground with digital ground through a ferrite, so that i can avoid specific planes for it.

 

[berkeman]

Does a Ferrite have particular frequency response? Say a 200E Ferrite and a 120E ferrite, do they have frequency characteristics?
i want to isolate my Analog ground with digital ground through a ferrite, so that i can avoid specific planes for it.

http://www.fair-rite.com/cgibin/catalog.pgm


.