Jitter is obtained in two ways, both of which first simulate pnoise.The first one gets pnoise curve, pnoise at various points from 1k to 10M, and then puts this value in matlab.
The second one is jitter directly through JCC or jc.
The first result is orders of magnitude larger, and that's why.
Integral procedure under the net, as follows, I think there should be no mistake
function Jitter = Pn2Jitter(f, Lf, fc)
%
% Summary: Jitter (RMS) calculation from phase noise vs. frequency data.
%
% Calculates RMS jitter by integrating phase noise power data.
% Phase noise data can be derived from graphical information or an
% actual measurement data file.
%
% Usage:
% Jitter = Pn2Jitter(f, Lf, fc)
% Inputs:
% f: Frequency vector (phase noise break points), in Hz, row or column.
% Lf: Phase noise vector, in dBc/Hz, same dimensions, size(), as f.
% fc: Carrier frequency, in Hz, a scalar.
% Output:
% Jitter: RMS jitter, in seconds.
%
% Examples:
% [1] >> f = [10^0 10^1 10^3 10^4 10^6]; Lf = [-39 -73 -122 -131 -149];
% >> Jitter = Pn2Jitter(f, Lf, 70e6)
% Jitter = 2.3320e-011
% Comparing fordahl application note AN-02-3{*} and jittertime.com{+}
% calculations at fc = 70MHz
% Pn2Jitter.m: 23.320ps
% AN-02-3 (graphical method): 21.135ps
% AN-02-3 (numerical method): 24.11ps
% Aeroflex PN9000 computation: 24.56ps
% JitterTime.com calculation: 23.32ps
%
% {*} fordahl Application Note AN-02-3:
% "![]()
hase noise to Jitter conversion"
% http://fordahl.com/images/phasenoise.pdf
% As of 11 May 2007 it also appears here:
% http://www.metatech.com.hk/appnote/fordahl/pdf/e_AN-02-3.pdf
% http://www.metatech.com.tw/doc/appnote-fordahl/e-AN-02-3.pdf
%
% {+} JitterTime Consulting LLC web calculator
% http://www.jittertime.com/resources/pncalc.shtml
% As of 5 May 2008
%
% [2] >> f = [10^2 10^3 10^4 10^5 10^6 10^7 4.6*10^9];
% >> Lf = [-82 -80 -77 -112 -134 -146 -146 ]; format long
% >> Jitter = Pn2Jitter(f, Lf, 2.25e9)
% Jitter = 1.566598599875678e-012
% Comparing ADI application note{$} calculations at fc = 2.25GHz
% Pn2Jitter.m: 1.56659859987568ps
% MT-008: 1.57ps
% Raltron {&}: 1.56659857673259ps
% JitterTime: 1.529ps--excluding the (4.6GHz, -146) data point,
% as 1GHz is the maximum allowed
% {$} Analog Devices, Inc. (ADI) application note MT-008:
% "Converting Oscillator Phase Noise to Time Jitter"
% http://www.analog.com/en/content/0,2886,760%255F%255F91502,00.html
% {&} Raltron web RMS Phase Jitter calculator:
% "Convert SSB phase noise to jitter"
% http://www.raltron.com/cust/tools/osc.asp
% Note: Raltron is restricted to f(min) = 10Hz;
% therefore it cannot be used in this example [1].
%
% [3] >> f = [10^2 10^3 10^4 200*10^6]; Lf = [-125 -150 -174 -174];
% >> Jitter = Pn2Jitter(f, Lf, 100e6)
% Jitter = 6.4346e-014
% Comparing ADI application note{$} calculations at fc = 100MHz
% Pn2Jitter.m: 0.064346ps
% MT-008: 0.064ps
% JitterTime: 0.065ps
%
% Note:
% f and Lf must be the same length, lest you get an error and this
% Improbable Result: Jitter = 42 + 42i.
%
% (A spreadsheet, noise.xls, is available from Wenzel Associates, Inc. at
% http://www.wenzel.com, "Allan Variance from Phase Noise."
% It requires as input tangents to the plotted measured phase noise data,
% with slopes of 1/(f^n)--not the actual data itself--for the
% calculation. The app. note from fordahl discusses this method, in
% addition to numerical, to calculate jitter. This graphical straight-
% line approximation integration technique tends to underestimate total
% RMS jitter.)
%
% [4] Data can also be imported directly from an Aeroflex PN9000 ASCII
% file, after removing extraneous text. How to do it:
% (1) In Excel, import the PN9000 data file as Tab-delimited data,
% (2) Remove superfluous columns and first 3 rows, leaving 2 columns
% with frequency (Hz) and Lf (dBc/Hz) data only.
% (With the new PN9000 as of April 2006, only the first row
% is to be removed, and there are only two columns.
% I may take advantage of this in an updated version of this
% program,thereby eliminating the need to edit the data),
% (3) Save As -> Text (MS-DOS) (*.txt), e.g., a:\Stuff.txt,
% (4) At the MATLAB Command Window prompt:
% >> load 'a:\Stuff.txt' -ascii
% Now Stuff is a MATLAB workspace variable with the
% phase noise data,
% (5) >> Pn2Jitter(Stuff(:,1), Stuff(:,2), fc);
% (assuming fc has been defined)
% One 10MHz carrier data set resulted in the following:
% Pn2Jitter.m: 368.33fs
% PN9000 calculation: 375fs
%
% Runs at least as far back as MATLAB version 5.3 (R11.1).
%
% Copyright (c) 2005 by Arne Buck, Axolotol Design, Inc. Friday 13 May 2005
% arne (d 0 t) buck [a +] alum {D o +} mit (d 0 +} e d u
% $Revision: 1.2 $ $Date: 2005/05/13 23:42:42 $
%
% License to use and modify this code is granted freely, without warranty,
% to all as long as the original author is referenced and attributed
% as such. The original author maintains the right to be solely
% associated with this work. So there.
% Bug fixes to resolve problematic data resulting in division by 0, or
% excessive exponents beyond MATLAB's capability of realmin (2.2251e-308)
% and realmax (1.7977e+308); no demonstrable effect on jitter calculation
% AB 18May2005 Fix /0 bug for *exactly* -10.000dB difference in adjacent Lf
% AB 24May2005 Fix large and small exponents resulting from PN9000 data
% AB 11May2007 Improve documentation, update URLs
% AB 5May2008 Verify and update URLs
tic
%% It's almost nine o'clock. We've got to go to work.
L = length(Lf);
if L == length(f)
% Fix ill-conditioned data.
I=find(diff(Lf) == -10); Lf(I) = Lf(I) + I/10^6; % Diddle adjacent Lf with
% a diff=-10.00dB, avoid ai:/0
% Just say "No" to For loops.
lp = L - 1; Lfm = Lf(1:lp); LfM = Lf(2![]()
); % m~car+, M=cdr
fm = f(1:lp); fM = f(2![]()
); ai = (LfM-Lfm) ./ (log10(fM) - log10(fm));
% Cull out problematic fine-sieve data from the PN9000.
Iinf = find( (fm.^(-ai/10) == inf) | fm.^(-ai/10)<10^(-300)); % Find Inf
fm(Iinf) = []; fM(Iinf-1) = []; Lfm(Iinf) = []; LfM(Iinf-1) = [];
ai(Iinf) = []; f(Iinf) = []; Lf(Iinf) = [];
% Where's the beef?
Jitter = ...
1/(2*pi*fc)*sqrt(2*sum( 10.^(Lfm/10) .* (fm.^(-ai/10)) ./ (ai/10+1)...
.* (fM.^(ai/10+1) - fm.^(ai/10+1)) ));
else
disp('> > Oops!');
disp('> > > The f&Lf vector lengths are unequal. Where''s the data?')
Jitter = sqrt(sqrt(-12446784));
end % if L
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