# phase-continous FSK

import math
import matplotlib.pyplot as plt

Fs = 10000 # sample rate

f0 = 100 # bit 0
f1 = 200 # bit 1

bits = [0, 1, 0, 1]

samples_per_bit = 500

phase = 0

time = []
signal = []

for bit in bits:
    # Selct frequency based on bit
    if bit == 0:
        f = f0
    else:
        f = f1
    
    # Generate sample for this bit
    for i in range(samples_per_bit):
        # Advance phase
        phase += 2 * math.pi * f / Fs
        # Generate carrier
        sample = math.cos(phase)

        time.append(len(time) / Fs)
        signal.append(sample)

plt.plot(time, signal)
plt.xlabel("Time (seconds)")
plt.ylabel("Amplitude")
plt.title("Phase-Continuous FSK")
plt.grid()
plt.show()