標題: FLICKER NOISE IN CMOS LC OSCILLATORS国外硕士论文 [打印本頁] 作者: qitianhua 時間: 2009-10-10 09:11 PM 標題: FLICKER NOISE IN CMOS LC OSCILLATORS国外硕士论文 A Thesis Presented to The Academic Faculty 3 z4 }( s! e1 V+ kBy Dale Scott Douglas In Partial Fulfillment Of the Requirements for the Degree7 Q: _/ |8 Q, p
Master of Science in Electrical and Computer Engineering / ?' a9 |. r* wGeorgia Institute of Technology ) _ q- Y6 j9 H" E/ \December, 2008& ^& N+ l. o9 v v, N* [. f
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! r' f* @% O# |2 t6 |8 j0 l' C0 XSUMMARY " t& X' g1 N. o* e3 ySources of flicker noise generation in the cross-coupled negative resistance oscillator , h% J6 y1 |4 d! t1 Y(NMOS, PMOS, and CMOS) are explored. Also, prior and current work in the area of + i3 ]3 \- g% O8 |( j6 Yphase noise modeling is reviewed, including the work of Leeson, Hajimiri, Hegazi, and * W: T, { ] U7 }others, seeking the mechanisms by which flicker noise is upconverted. * @3 N" D8 L6 c; x S; k1 qA Figure of Merit (FOM) methodology suitable to the 1/f3 phase noise region is also1 \& l2 d8 _1 O. F4 L7 y5 }5 @
developed, which allows a new quantity, FOM1, to be defined. FOM1 is proportional to! t5 c% D" u" O0 Q( x1 G
flicker noise upconverted, thus allowing the effectiveness of flicker noise upconversion ' e4 m4 ~ k" Q; A5 @suppression techniques to be evaluated, despite possibly changing bias points or tank Q,9 Y8 n3 q' m3 c" F, |3 b
which would change phase noise and FOM in the 1/f2 region. 6 \) e% C8 y' ~' n j8 A2 d0 tThe work of Hajimiri is extended with a simple ΛDC estimator for the special case of7 y5 d) N! f4 g. X' E
LC CMOS oscillators. A method of adaptive control of an oscillator core is presented, as! z7 C- p# T. w6 Y: x, U1 E
well, comprised of a CMOS oscillator with a digitally adjustable N and P width, and a i- h# _# h; W- m0 Q( B7 ^1 Z
circuit (which is essentially a tracking ADC) which repeatedly adjusts the relative N to P 3 E3 P# M( G( A4 O& ^, nwidth dependent on the ΛDC estimate to maintain the condition of minimum flicker noise ! [. t& T# H3 }, `; Xupconversion. A fixed calibration constant is sufficient to allow convergence to within & A1 N" G# c9 t+ ~+ Q0.7dB of optimal FOM1 for all cases of N width, for a varactorless oscillator test cell. ' n8 G7 Q/ K7 c! c* [/ T, pFinally, a circuit is proposed which would allow the flicker noise reduction technique' e& d4 C- C0 W' w9 Q; h
of cycling to accumulation to be applied to continuous time oscillators, but is not- ]( U- L' T% }/ x% ?/ \6 q) b
rigorously vetted.