Reg Edwards wrote:

Regardless of an amplifier's gain, the signal to noise ratio at its
output remains the same as the signal to noise ratio at its input.

Obviously - if its a linear amplifier!

I'm afraid this is quite wrong

Your statement would be a correct one if and only if the amplifier is a
non-noisy one - which, alas, is not a real case...

--
73 es 51 de i3hev, op. mario

Il vero Radioamatore si riconosce... dal call in firma!
- Campagna 2005 "Sono un Radioamatore e me ne vanto"

it.hobby.radioamatori.moderato
http://digilander.libero.it/hamweb
http://digilander.libero.it/esperantovenezia

"i3hev, mario held" wrote
Reg Edwards wrote:

Regardless of an amplifier's gain, the signal to noise ratio at
its
output remains the same as the signal to noise ratio at its input.

Obviously - if its a linear amplifier!

I'm afraid this is quite wrong

Your statement would be a correct one if and only if the amplifier
is a
non-noisy one - which, alas, is not a real case...

===================================

If an amplifier incorporates a noise generator or also behaves as a
filter, then it is no longer just an amplifier. My statement is quite
correct.
----
Reg.

Reg Edwards wrote:

If an amplifier incorporates a noise generator...
... then it is no longer just an amplifier. ....

.... so, we must conclude that amplifiers do not exist!

of course, there is no real amplifying device which does not generate
noise; or, more precisely, there is no non-noisy real device at all

If you choose not to call "amplifier" a device which amplifies signals
if it has a non-unity noise figure, please feel free to do so - we live
in a (at least partially) free world... but you will be alone! )

Regards!
--
73 es 51 de i3hev, op. mario

it.hobby.radioamatori.moderato
http://digilander.libero.it/hamweb
http://digilander.libero.it/esperantovenezia

i3hev, mario held wrote:
Reg Edwards wrote:

If an amplifier incorporates a noise generator...
... then it is no longer just an amplifier. ....

... so, we must conclude that amplifiers do not exist!

of course, there is no real amplifying device which does not generate
noise; or, more precisely, there is no non-noisy real device at all

If you choose not to call "amplifier" a device which amplifies signals
if it has a non-unity noise figure, please feel free to do so - we live
in a (at least partially) free world... but you will be alone! )

Regards!

Don't be too hasty. Reg has verified he's got some coax that's much
lower loss than anyone else can buy (it actually meets the predictions
of his coax loss program), and has verified it by measuring it many
times. Maybe he also has a secret source of noise-free amplifiers. You
never know.

Roy Lewallen, W7EL