On 12/4/08 2:14 AM, "Grant Hodgson" <[EMAIL PROTECTED]> wrote:
> Jim
>
> Figures such as -200dBc/Hz probably relate to the phase noise figure of
> merit which some PLL suppliers like Nat. Semi, Hittite and AD use to
> compare various PLL offerings. These figures are normalised to a 1Hz
> comparison frequency and unity division ratio; to get a prediction of
> PLL phase noise within the loop bandwidth you need to scale for both
> comparison frequency and division ratio. This FOM is somewhat crude, as
> it doesn't take into account flicker noise, amongst other things, and
> loses accuracy with very high comparison frequencies. Banerjee goes
> into more detail about this subject.
>
> regards
>
> Grant
>
I found my copy of Banerjee and you're right. The next thing I have to do
is track down Sal Kayalar at JPL and find out where he came up with the
other numbers I cited (from the IPN progress report by Cook in 2004.. The
footnote references an internal JPL memo, from my section, no less, but I
haven't found it yet) and see if they're directly comparable. (i.e. Has
technology really improved by 40dB in 15 years?) I'm pretty sure they're
not directly comparable.
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