Python中正弦波发生器的不同频率

Question

I am using the code below to generate a sine wave and it works fine. However, when I try to use large frequencies 500kHz and change the time period to 0.2us I expect to get a full sine wave with time period of 0.2us but what I get is just a straight line don't know why.

def sampled_sine_wave(freq):
    samples = 1000
    time_period = 2e-7
    time = linspace(0,time_period,samples)
    _ = plot(time,[sin(t*freq*2*np.pi) for t in time], linewidth=2)
    Vin1=([np.sin(t*freq*2*np.pi) for t in time])
    #print (Vin1)
return Vin1

Can somebody tell me why I am getting that and how can I solve it. Thanks

Answer 1

As mentioned in the comments, you probably aren't actually getting a straight line . If you graph it in that range, it looks almost like a straight line. In fact, at the edge of that range, at x=2e-7 , that sine function and 5e5*x have less than a 7% difference . You probably meant to use a full period, time_period = 2e-6 , which looks more like a sine wave . You seem to know that the period of that function is 2 microseconds, but 2 microseconds is 2e-6 seconds, not 2e-7 seconds .

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Wow, this took a while to write for such a short answer. I kept messing up and dividing by pi instead of multiplying and pasting the wrong links.