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# Help Matblab code about "phase noise"

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#### bkhoa

##### Newbie level 2
matlab dbc file

1. The phase noise due to laser diode
2. The phase noise due to Local oscillator

phase noise dbc/hz matlab

bkhoa said:
1. The phase noise due to laser diode
2. The phase noise due to Local oscillator

this is for OSCILLATOR:

Description:
function Sout = add_phase_noise( Sin, Fs, phase_noise_freq, phase_noise_power )

Oscillator Phase Noise Model

INPUT:
Sin - input COMPLEX signal
Fs - sampling frequency ( in Hz ) of Sin
phase_noise_freq - frequencies at which SSB Phase Noise is defined (offset from carrier in Hz)
phase_noise_power - SSB Phase Noise power ( in dBc/Hz )

OUTPUT:
Sout - output COMPLEX phase noised signal

NOTE:
Input signal should be complex

EXAMPLE ( How to use add_phase_noise ):
Assume SSB Phase Noise is specified as follows:
-------------------------------------------------------
| Offset From Carrier | Phase Noise |
-------------------------------------------------------
| 1 kHz | -84 dBc/Hz |
| 10 kHz | -100 dBc/Hz |
| 100 kHz | -96 dBc/Hz |
| 1 MHz | -109 dBc/Hz |
| 10 MHz | -122 dBc/Hz |
-------------------------------------------------------

Assume that we have 10000 samples of complex sinusoid of frequency 3 KHz
sampled at frequency 40MHz:

Fc = 3e3; % carrier frequency
Fs = 40e6; % sampling frequency
t = 0:9999;
S = exp(j*2*pi*Fc/Fs*t); % complex sinusoid

Then, to produse phase noised signal S1 from the original signal S run follows:

Fs = 40e6;
phase_noise_freq = [ 1e3, 10e3, 100e3, 1e6, 10e6 ]; % Offset From Carrier
phase_noise_power = [ -84, -100, -96, -109, -122 ]; % Phase Noise power
S1 = add_phase_noise( S, Fs, phase_noise_freq, phase_noise_power );

hi
i have a problem about the matlab code of diode equation for noise given below

k = 1.38e-23;
q = 1.6e-19;
t1 = 273 + 25;
vt = k*t1/q;
df=0.001;
f =[0:df:100]
kf=1.0e-26;
af=1.2;
v1=0.7;
%v1 =0.25:0.05:1.1;
id = 1.0e-12*(exp(v1/(2.0*vt)));
%pst= 2*q*id;
psflk= kf*(id.^af/f);
plot(f,psflk,'b')
xlabel('frequency (khz)')
ylabel('sflk (A/hz2)')
axis([0,2, 0, 0.0015])

i need the plot in psflk and frequency(f)
so pls help me

thanks

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