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原文連結
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% w0 I8 J$ ~- l4 \4 ^以下原文內容:
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Calculating Large Signal Phase Noise Using Transient Noise Analysis
% K! s: S7 r; @By Alan Whittaker on March 26, 2009
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1 v Z; m/ ^. A; Y5 G) A1 oMy name is Alan Whittaker and I'm in Cadence's Custom IC Proliferation Group.
8 H6 n- G* ~( F$ d1 EWe support Cadence's Technical Field Organization (the AEs) and Cadence customers
+ l3 n& s/ V& Pduring the introduction and adoption of new and advanced EDA technologies. I'll ' ^7 e9 i+ w4 w6 b8 i5 V" k
be posting here from time to time on methodologies and tool features that # g8 k: t& a: U5 J7 Z
resolve issues that users have run into during the front-end analog, RF and
) s0 M: j/ r: ^. y, E ]* n ], imixed-signal design process.2 N( g& H. r8 d7 `
3 p8 M9 K/ O5 H% p& JI'm first going to address how you can perform a large-signal phase noise $ N- N5 ~# [6 i9 S2 M3 b
analysis on a design block such as a VCO using our transient noise analysis
* D A$ k8 e- q8 f) T' F6 S' n; _capability in our Spectre circuit simulator. This approach is in addition to 1 P) H' l7 j: U; I
our small signal phase noise analysis which is available using either pnoise 1 @" T* O) j9 K; v6 K7 f7 \
or hbnoise analysis in the SpectreRF option to Spectre.
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Here are the steps to obtain a phase noise plot from transient noise analysis:% v2 Y6 b& l( ]- E
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1. Set up your oscillator testbench circuit for a transient noise analysis
2 Y9 h8 O+ G8 B3 P/ r1 j(See sourcelink for the Transient Noise appNote - it doesn't discuss the phase . j4 k, Y* B, i# q, x& _6 {
noise 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 % C5 A* X; |# X K; ]( D2 s( V# R0 y
($CDSHOME/tools//dfII/samples/artist/pllMMLib) 2 m2 i' i) p2 K t' C, A4 t
to the testbench circuit. Important: The instance name for this block must be 5 a0 a) J# S& k; X
'vco_freq'.
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6 r) ]' T8 [% {$ B, IIf the oscillator output is differential, connect it to the vin_p and vin_n
3 e: J' [+ H' e; c/ z$ |$ Zpins on the freq_meter block. If the oscillator output is single ended, connect 9 u& @5 I2 R0 g2 L
it to the vin_p pin and connect the vin_n pin to ground. Connect a noConn cell ; c) i) Z+ ]" n* G" l0 H( G
from the basic library to the out_freq pin. |
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