LFM-MSK Spectrum Constraint Method Based on Pulse Edge Correction

The combination of radar and communication makes them give full play to their respective advantages such as high power and wide bandwidth, therefore, the integration of radar communication has recently received widespread attention. The design of the integrated signal is the key to achieve integration. Linear Frequency Modulation-Minimum Shift Keying (LFM-MSK) modulates the communication information to the LFM signal via MSK. LFM-MSK combines the features of LFM and MSK. However, it has a problem of spectrum extension. This leads to severe neighbor frequency interference, which has a great impact on the performance of the system. To solve this problem, this paper proposes an LFM-MSK spectrum constraint method based on pulse edge correction. The first step is to derive the number of codes to be adjusted. Then the special MSK signal is modulated at the edge of the LFM. Simulation results show that after the edge correction, the spectrum expansion is significantly improved and the spectrum of LFM-MSK is constrained to the design bandwidth. This avoids interference from adjacent channels and improves the electromagnetic compatibility of the electronic system. The innovation of this paper is to propose a special MSK modulation method on the LFM edge to solve the problem of LFM-MSK spectrum expansion.