Question

I would like to generate a digital signal, which’ll then be used to implement an ASK(Amplitude Shift Keying) Signal.

Let’s say the message bits are 10110, data rate : 3.9 Khz & amplitude A.

What would be the best way to generate a Square signal(Digital).

I tried the following code, but the outcome is not a desired one.

double[] x = new double[1000];
double[] y = new double[1000];
double freq = 3900.0;

for (int k = 0; k < y.Length; k++)
{
    x[k] = k;
    y[k] = (4 / Math.PI) * (((Math.Sin(((2 * k) - 1) * (2 * Math.PI * freq))) /   ((2 * k) - 1)));
}

// Plot Square Wave
plotSquare(x, y, Msg);

Answer 1

The easiest way I can think of is to set y to be sign of a sine wave, making allowances for when it equals zero. I don’t know if C# has the triple-operator, but something like this might work:

y[k] = Math.Sin(freq * k)>=0?A:-1*A;