
From:  Ahmed Husain ?Abbas Mohamed Sahrab 
Subject:  Questions regarding signal processing in octave 
Date:  Thu, 10 Nov 2016 11:19:47 +0000 
We are a group of college students doing a project about signal processing. We would like to compute the PSD(Power Spectral Density) and the Power Spectrum, our question is how to find the Power Spectrum and how to use different frame sizes e.g. 128, 256, 512. We used this following code to find the PSD
NFFT=32768; F=fft(y,NFFT); F_Shift=fftshift(F);
Px=F_Shift.*conj(F_Shift)/(NFFT*L);
We tried using a NFFT of 1024 but we literally got two intersecting lines
Our Second question is about sine waves, we have a wave with the following specification
x = A1*sin(2*pi*f1*t) Sampling Frequency = 100 kHz =Fs Frequency = 10 kHz = F1 Amplitude = 0.1 = A1
(fs=f*N) in which f is the frequency and N is the amount of samples needed. but in the question we already have the fs which is 100kHz so how are we supposed to generate 1000 samples?
Should we use
t= 0:ts: Tfinal
until we have 1000 values in the t variable?
Best Wishes
Students of Polytechnic Bahrain 
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