怎么把差分改为非差分

import numpy as np

# 生成原始数据信号
data = np.random.randint(0, 2, size=(n,))
print('原始数据：', data)

# 将数据映射为符号序列
symbol = np.zeros((n//2,))
for i in range(0, n, 2):
    if data[i] == 0 and data[i+1] == 0:
        symbol[i//2] = -1 - 1j
    elif data[i] == 0 and data[i+1] == 1:
        symbol[i//2] = -1 + 1j
    elif data[i] == 1 and data[i+1] == 0:
        symbol[i//2] = 1 - 1j
    else:
        symbol[i//2] = 1 + 1j
print('映射后的符号序列：', symbol)

# 添加同步前缀（可选）

# 基带滤波

# 调制为模拟信号

# 添加高斯噪声

# 解调和解符号操作
demodulation = np.zeros((n,))
for i in range(n//2):
    if symbol[i] == -1 - 1j:
        demodulation[i*2] = 0
        demodulation[i*2+1] = 0
    elif symbol[i] == -1 + 1j:
        demodulation[i*2] = 0
        demodulation[i*2+1] = 1
    elif symbol[i] == 1 - 1j:
        demodulation[i*2] = 1
        demodulation[i*2+1] = 0
    else:
        demodulation[i*2] = 1
        demodulation[i*2+1] = 1
print('解调和解符号后的数据：', demodulation)

# 性能评估
error = np.sum(np.abs(demodulation - data))
BER = error / n
print('误码率：', BER)