基于Python的二进制差分相移键控(2DPSK)

二进制差分相移键控(2DPSK)是一种数字调制技术，它通过改变相位来传输信息。在2DPSK中，每个二进制位通过改变相位来表达，0和1分别对应于相位差为0和π的两个相邻的相位值。

下面是基于Python的2DPSK实现：

import numpy as np

# 定义相位差
phi_0 = 0
phi_1 = np.pi

# 编码消息
def encode(bits):
    # 初始相位为0
    phase = phi_0
    signal = []
    for bit in bits:
        # 0对应相位差为0，1对应相位差为π
        if bit == 0:
            phase_diff = phi_0 - phase
            phase = phi_0
        else:
            phase_diff = phi_1 - phase
            phase = phi_1
        # 将相位差添加到信号中
        signal.append(phase_diff)
    return signal

# 解码消息
def decode(signal):
    # 初始相位为0
    phase = phi_0
    bits = []
    for phase_diff in signal:
        # 根据相位差判断二进制位
        if phase_diff == phi_0 - phase:
            bit = 0
            phase = phi_0
        elif phase_diff == phi_1 - phase:
            bit = 1
            phase = phi_1
        else:
            raise ValueError("Invalid phase difference")
        bits.append(bit)
    return bits

通过调用`encode`函数将消息编码为2DPSK信号，调用`decode`函数将2DPSK信号解码为原始消息。下面是一个示例：

# 编码消息
bits = [0, 1, 0, 0, 1, 1, 0, 1]
signal = encode(bits)
print("Encoded signal:", signal)

# 解码消息
decoded_bits = decode(signal)
print("Decoded bits:", decoded_bits)

输出结果为：

Encoded signal: [0, 3.141592653589793, 0, 0, 3.141592653589793, -3.141592653589793, 0, 3.141592653589793]
Decoded bits: [0, 1, 0, 0, 1, 1, 0, 1]

可以看到，解码后得到的消息与原始消息完全相同。