A Novel DME Pulse Waveform for EMC Optimization with L-DACS1

The development, testing, and performance verification of Distance Measuring Equipment (DME) use signals in Gaussian double pulse modulation format. In addition, L-band Digital Aeronautical Communications System 1 (L-DACS1) is a candidate technology for the future ground-to-air data chain for aviation communication, and DME is its main source of interference. In this paper, smooth trapezoidal pulse waveform is proposed, which can guarantee the ranging performance of DME and provide lower interference than conventional Gaussian pulses to further improve the electromagnetic compatibility with the L-DACS1 system. The alternative pulse waveform conforms to the pulse shape requirements in the current DME specification to maintain compatibility with existing DME ground transponders and avionics. The pulse signal proposed in this paper solves the spectral over-widening problem caused by a too-fast rising edge. Therefore, even when transmitting at the same high power of 1000 Watts as conventional Gaussian pulses, the interference to adjacent channels is very small. In this paper, under the background of the coexistence of DME and L-DACS1 systems, it is verified that smooth trapezoidal pulse modulation signals can effectively improve the electromagnetic compatibility of the two and improve the transmission performance of the system.