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python signal processing
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python signal processing
#1
CSV file contain a row of 1000 signals.

1. Compute the discrete fourier transform (DFT) of the signal s. Show a plot of the magnitude of the DFT. 
2. Assume this signal was sampled at a rate of 44,100 Hz. How many distinct sinusoidal components are in the signal and what are the frequencies? my question here
3. Repeat the first two questions but for s1(n) = s(n)w(n) (pointwise multiplication) where w is a triangular window. Assume N = 1000.
w(n) = 1 - |(n-(N−1)/2)/(N/2)|

So, first task I did in this way:
import pandas as pd
import numpy as np
from matplotlib import pyplot as plt
tt = pd.read_csv('us-data.csv', header=None)
x = tt.values[0, :]

f = 2 * np.pi * (1/30.0)

s1 = np.sin(f * x)
S1 = np.fft.fft(s1)
plt.figure(1)
plt.plot(np.abs(S1))
plt.show()
I don't understand the second one, not saying about the third one. Please, can you give me some hints. Maybe a little explanation of what to do.
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