import math
import matplotlib.pyplot as plt

sample_rate = 100000
baud_rate = 48000
f0 = 1000
f1 = 2000

message = "HELLO"

phase = 0
freq = 0

samples_per_bit = int(sample_rate/baud_rate)

values = []

for c in message:
    bword = format(ord(c), '08b')
    for bit in bword:
        if bit == '0':
            freq = f0
        else:
            freq = f1
        for i in range(samples_per_bit):
            phase += 2 * math.pi * (freq/sample_rate)
            values.append(math.cos(phase))

plt.plot(values)
plt.show()