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原文連結
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, h1 k( b" ~! P. ^9 h! T `4 ^- c1 J以下原文內容:, G9 |+ e* M) x% }: V1 v
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Calculating Large Signal Phase Noise Using Transient Noise Analysis* E( `. x4 K" t9 [, n& F
By Alan Whittaker on March 26, 20095 i) Z3 Q6 r; d' Z
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My name is Alan Whittaker and I'm in Cadence's Custom IC Proliferation Group. x6 [* W& c4 T! d1 x
We support Cadence's Technical Field Organization (the AEs) and Cadence customers % E7 I: e5 Y3 H; L! p
during the introduction and adoption of new and advanced EDA technologies. I'll
+ J/ i# f. V. O ]) x, t: z7 J5 h2 Cbe posting here from time to time on methodologies and tool features that " B9 M* j3 |. ]$ B0 W7 ]
resolve issues that users have run into during the front-end analog, RF and * }, }- Q! h! b! K. K+ y1 ]( Y3 z
mixed-signal design process.
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I'm first going to address how you can perform a large-signal phase noise 1 x9 ~- L" ^% U$ y) D' `
analysis on a design block such as a VCO using our transient noise analysis 0 V6 a8 p: @ ^/ L. u+ }
capability in our Spectre circuit simulator. This approach is in addition to ; O* s" a- P* O6 j/ Y* a
our small signal phase noise analysis which is available using either pnoise
0 w( K4 Q7 l4 W: I4 {+ M' H4 Oor hbnoise analysis in the SpectreRF option to Spectre.) J. _* D7 j' _* i
# c. }! e) d: ^- [' xHere are the steps to obtain a phase noise plot from transient noise analysis:3 v$ s( s, X" M% }9 d0 }3 a
) ~& K& ~- A9 h% ^ d- o. r1. Set up your oscillator testbench circuit for a transient noise analysis % D$ T) z% H; n2 w7 M' T$ S
(See sourcelink for the Transient Noise appNote - it doesn't discuss the phase
! E& r" s+ Z8 L+ P. M% fnoise measurement, but describes how to properly set up the simulation analysis
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2. Add the block freq_meter from the pllMMLib library
3 q4 ^) }; U* Q. a($CDSHOME/tools//dfII/samples/artist/pllMMLib) . K- K, W- P) g4 X+ ]4 A
to the testbench circuit. Important: The instance name for this block must be
0 e( i, y8 q P/ s2 z+ F'vco_freq'.; c( q& y+ J1 ~; n% S
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If the oscillator output is differential, connect it to the vin_p and vin_n & M4 J" h/ h% d3 ]" w# N
pins on the freq_meter block. If the oscillator output is single ended, connect * @# `6 m1 M3 M3 D$ C7 l0 h
it to the vin_p pin and connect the vin_n pin to ground. Connect a noConn cell
$ H6 b4 U% b/ S1 d! gfrom the basic library to the out_freq pin. |
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