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原文連結
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Calculating Large Signal Phase Noise Using Transient Noise Analysis8 R1 V8 u. b/ [2 H
By Alan Whittaker on March 26, 2009
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: n9 c; t0 t* B; f$ z j4 K- H: `, DMy name is Alan Whittaker and I'm in Cadence's Custom IC Proliferation Group.
, J3 O$ R; L, C+ fWe support Cadence's Technical Field Organization (the AEs) and Cadence customers
" a K1 `" }" x0 H1 L0 rduring the introduction and adoption of new and advanced EDA technologies. I'll
2 E# W/ w: v4 D( d& Zbe posting here from time to time on methodologies and tool features that $ v' ~# j( G& B9 {
resolve issues that users have run into during the front-end analog, RF and
" g1 f/ g/ Q$ {% o# m b- U" |mixed-signal design process.6 x: f- g, U: e3 X5 R/ I) N2 Q5 X
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I'm first going to address how you can perform a large-signal phase noise
8 s) d( t4 W4 ^analysis on a design block such as a VCO using our transient noise analysis
/ b0 W3 v1 ]1 z; E g, d/ Icapability in our Spectre circuit simulator. This approach is in addition to % D+ ~3 ^, `' [; M+ S2 H
our small signal phase noise analysis which is available using either pnoise / }( ]) g/ u9 [* W6 r
or hbnoise analysis in the SpectreRF option to Spectre.1 l" f/ j6 n9 Q5 S8 G7 F
4 E1 W% Y% H' ?9 Q; NHere are the steps to obtain a phase noise plot from transient noise analysis: `6 e: C, u+ s% W3 e
q2 S* `7 y+ I$ U& R% X1. Set up your oscillator testbench circuit for a transient noise analysis ! z4 ^. H$ P0 K' q5 w
(See sourcelink for the Transient Noise appNote - it doesn't discuss the phase 3 o0 l8 i8 V- W C: m; \
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
- {( w3 D, O+ g% @($CDSHOME/tools//dfII/samples/artist/pllMMLib)
6 W8 c$ G3 ~4 k tto the testbench circuit. Important: The instance name for this block must be
# J6 l3 ~/ | X'vco_freq'.
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If the oscillator output is differential, connect it to the vin_p and vin_n . w' \% [/ f7 Q: D
pins on the freq_meter block. If the oscillator output is single ended, connect
4 o$ j1 P' h, @6 g& Uit to the vin_p pin and connect the vin_n pin to ground. Connect a noConn cell 3 u- a5 d- @' @% m7 }$ Q- [2 w1 `0 K
from the basic library to the out_freq pin. |
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