python实现IQ解调代码

在Python中实现IQ解调（In-phase and Quadrature Demodulation），通常是在处理数字信号处理任务，特别是在无线通信领域，用于恢复模拟信号从数字基带表示的形式。 IQ解调是将复数调制信号转换回其原始幅度和相位信息的过程。下面是一个简单的IQ解调的基本步骤：

import numpy as np

def iqd_demodulator(samples, carrier_frequency=0, sample_rate=None):
    """
    IQ demodulation using complex multiplication.
    
    Args:
        samples (numpy array): Complex baseband samples representing the modulated signal.
        carrier_frequency (float): The frequency of the carrier wave in Hz.
        sample_rate (float): The sampling rate in Hz. If None, it's assumed to be the Nyquist rate for the given carrier.

    Returns:
        tuple: Tuple containing amplitude and phase signals after demodulation.
    """
    # If sample_rate is not provided, calculate from carrier_frequency assuming a Nyquist rate
    if sample_rate is None:
        sample_rate = 2 * carrier_frequency

    # Perform IQ demodulation by multiplying with conjugate complex of carrier
    real_part = samples.real * np.cos(carrier_frequency * np.arange(len(samples)) / sample_rate) - \
                samples.imag * np.sin(carrier_frequency * np.arange(len(samples)) / sample_rate)
    imag_part = samples.real * np.sin(carrier_frequency * np.arange(len(samples)) / sample_rate) + \
                samples.imag * np.cos(carrier_frequency * np.arange(len(samples)) / sample_rate)

    # Return amplitude and phase components
    return (real_part, imag_part)

# Example usage
iq_samples = ...  # Your complex IQ data
demod_results = iqd_demodulator(iq_samples)
amplitude, phase = demod_results