[hpsdr] IP3 >+50 dBm ?

[Nico Palermo]

> IP3 != Dynamic Range.

... and it's worth remembering that every receiving system - even the
worst - has an arbitrarily large IP3, provided that an arbitrarily large
(and good) attenuator is inserted in front of it.

73s nico iv3nwv


> ***** High Performance Software Defined Radio Discussion List *****
>
> Ron:
>
> It is really simple.  IP3 is not dynamic range.  There is a formula for
> computing IP3 from imputed dynamic range when you mix two tones and get
> a third order product and measure its amplitude.
>
> But if the noise floor is raised,  you have lowered the SNR and
> therefore, CANNOT have the dynamic range implied by this computation.
>
> IP3 != Dynamic Range.
>
> Bob
>
>
> Ron Skelton wrote:
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>>
>>
>> ------------------------------------------------------------------------
>>
>> I don't comprehend the argument that such a high dynamic range is not
>> meaningful in view of the phase noise of oscillators and would
>> appreciate someone lightening my darkness.
>>
>> My understanding is that dynamic range is defined and bounded by noise
>> entering or created at the front end and the signal level where any
>> portion of the chain becomes saturated (for want of a better term). This
>> being so we can increase dynamic range by lowering the noise floor or by
>> increasing the point of saturation or both. The achievable noise floor
>> at HF and below  is determined by incoming not internal noise.  In any
>> event it seems to me the highest possible point of saturation is
>> required assuming the usual case of exposure to high levels of unwanted
>> signals.
>>
>>
>>
>
>
> --
> AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL,
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