Research on a Broadband Digital Receiver Based on Envelope Differentiation

In modern electronic reconnaissance systems, digital receivers play an important role in receiving a variety of complex signals, in which signal-to-time extraction is a key issue, but traditional methods often rely on the signal envelope, which is easily affected by the value of the threshold setting and the signal-to-noise ratio (SNR) of the signal. In fact, the pulse envelope front has a large derivative, which leads the envelope differentiation to show sharp peaks. In this paper, a time of arrival (TOA) extraction method based on first-order envelope differentiation of the signal is proposed. The method realizes the normalized extraction of different modulated signals by estimating the location where the sharp peaks appear, and it is not easily affected by the threshold setting. The processing flow of the digital receiver is as follows: the signal is first processed by digital channelization, and, after channelization, it passes through the signal detection module; then, after envelope differentiation, the useful signal is filtered out according to the result, and, finally, the pulse descriptor word consisting of the pulse arrival time, pulse width, signal frequency, and signal amplitude is formed, which is convenient for the subsequent processing. The experimental results verify the effectiveness and reliability of the signal arrival time extraction method.