import random
def white_noise(low, high, nums, file):
    signal = [random.uniform(low, high) for x in range(nums)]
    with open(file, 'w') as f:
        for i in range (0, nums, 3):
            line = signal[i:i+3]
            f.write(','.join(str(x) for x in line) + '\n')
    return signal