Abstract: The DME signal of Gauss double pulse modulation format is applied to the development, debugging and performance verification of DME system.Because of the complexity and high cost of the special DME signal simulator, research staff often use the analog signal source with fast dual pulse modulation instead Based on DME signal requirements，this paper analyzed the possible problems of this substitution，and verified the power spectrum occupancy of Gauss double pulse and rectangular pulse modulation signals under different edge of pulse conditions by experimental tests.The results are consistent with the analysis，indicating the substitution has its limitations.

Key words: Gauss double pulse, Rectangular double pulse, Rise and fall times, Power spectrum