Method of generating QPSK signal and wideband frequency hopping signal based on parallel DDS
Huang Zitao, Peng Ming, Yang Wenbin, Wu Xinbo · 2019
In the field of communication terminal testing, wideband modulation and frequency hopping signals are required in order to adapt to the development of communication system. Single channel DDS is widely used to generate modulation and frequency hopping signals due to its advantages of low cost, low power consumption, high resolution and fast conversion time. However, the output range of single channel DDS is limited by the system clock, which can't produce digital signal with high sampling rate for high speed DAC. To overcome the limit of single channel DDS, this paper proposed a method based on parallel DDS, which can generate modulated signal and frequency hopping signal. The test Implemented on the hardware platform with FPGA and DAC proves that this method can produce these signals in the range of 0~GHz, the signal bandwidth is up to 80MHz, and the frequency hopping rate can reach 8000 hops per second. The performance of the method accords with the actual demand.