How to plot graph sine wave

Question

I have this signal :

from math import*
Fs=8000
f=500
sample=16
a=[0]*sample
for n in range(sample):
    a[n]=sin(2*pi*f*n/Fs)

How can I plot a graph (this sine wave)?

and create name of xlabel as 'voltage(V)' and ylabel as 'sample(n)'

What code to do this?

Answer 1

from math import *
Fs = 8000
f = 500
sample = 16
a = [0] * sample
for n in range(sample):
    a[n] = sin(2*pi*f*n/Fs)

creating the x coordinates

Sample = [i for i in range(sample)]

importing matplotlib for plotting

import matplotlib.pyplot as plt

adding labels and plotting

plt.xlabel('Voltage(V)')
plt.ylabel('Sample(n)')
plt.plot(Sample, a)
plt.show()

Answer 2

• Setting the x-axis with np.arange(0, 1, 0.001) gives an array from 0 to 1 in 0.001 increments.
  • x = np.arange(0, 1, 0.001) returns an array of 1000 points from 0 to 1, and y = np.sin(2*np.pi*x) you will get the sin wave from 0 to 1 sampled 1000 times

I hope this will help:

import matplotlib.pyplot as plt
import numpy as np


Fs = 8000
f = 5
sample = 8000
x = np.arange(sample)
y = np.sin(2 * np.pi * f * x / Fs)
plt.plot(x, y)
plt.xlabel('sample(n)')
plt.ylabel('voltage(V)')
plt.show()

P.S.: For comfortable work you can use The Jupyter Notebook.

Answer 3

Yet another way to plot the sine wave.

import numpy as np
import matplotlib
matplotlib.use('TKAgg') #use matplotlib backend TKAgg (optional)
import matplotlib.pyplot as plt

t = np.linspace(0.0, 5.0, 50000)       # time axis
sig = np.sin(t)
plt.plot(t,sig)

Answer 4

This is another option

#!/usr/bin/env python

import numpy as np
import matplotlib
matplotlib.use('TKAgg') #use matplotlib backend TkAgg (optional)
import matplotlib.pyplot as plt

sample_rate = 200 # sampling frequency in Hz (atleast 2 times f)
t = np.linspace(0,5,sample_rate)    #time axis
f = 100 #Signal frequency in Hz
sig = np.sin(2*np.pi*f*(t/sample_rate))
plt.plot(t,sig)
plt.xlabel("Time")
plt.ylabel("Amplitude")
plt.tight_layout() 
plt.show()

Answer 5

import numpy as np
import matplotlib.pyplot as plt

F = 5.e2          # No. of cycles per second, F = 500 Hz
T = 2.e-3         # Time period, T = 2 ms
Fs = 50.e3        # No. of samples per second, Fs = 50 kHz
Ts = 1./Fs        # Sampling interval, Ts = 20 us
N = int(T/Ts)     # No. of samples for 2 ms, N = 100

t = np.linspace(0, T, N)
signal = np.sin(2*np.pi*F*t)

plt.plot(t, signal)
plt.xlabel('Time (s)')
plt.ylabel('Voltage (V)')
plt.show()

Answer 6

import matplotlib.pyplot as plt
import numpy as np
#%matplotlib inline
x=list(range(10))
def fun(k):
     return np.sin(k)
y=list(map(fun,x))
plt.plot(x,y,'-.')
#print(x)
#print(y)
plt.show()

Answer 7

A simple way to plot sine wave in python using matplotlib.

import numpy as np
import matplotlib.pyplot as plt


x=np.arange(0,3*np.pi,0.1)
y=np.sin(x)
plt.plot(x,y)
plt.title("SINE WAVE")
plt.show()

Answer 8

import matplotlib.pyplot as plt # For ploting
import numpy as np # to work with numerical data efficiently

fs = 100 # sample rate 
f = 2 # the frequency of the signal

x = np.arange(fs) # the points on the x axis for plotting
# compute the value (amplitude) of the sin wave at the for each sample
y = np.sin(2*np.pi*f * (x/fs)) 

#this instruction can only be used with IPython Notbook. 
% matplotlib inline
# showing the exact location of the smaples
plt.stem(x,y, 'r', )
plt.plot(x,y)

Answer 9

import math
import turtle

ws = turtle.Screen()
ws.bgcolor("lightblue")
fred = turtle.Turtle()
for angle in range(360):
    y = math.sin(math.radians(angle))
    fred.goto(angle, y * 80)

ws.exitonclick()

Answer 10

The window of usefulness has likely come and gone, but I was working at a similar problem. Here is my attempt at plotting sine using the turtle module.

from turtle import *
from math import *

#init turtle
T=Turtle()

#sample size
T.screen.setworldcoordinates(-1,-1,1,1) 

#speed up the turtle
T.speed(-1)

#range of hundredths from -1 to 1
xcoords=map(lambda x: x/100.0,xrange(-100,101))

#setup the origin
T.pu();T.goto(-1,0);T.pd()

#move turtle
for x in xcoords:
    T.goto(x,sin(xcoords.index(x)))