2CPFSK (continuous-phase frequency-shift keying) digital-modulation super-Nyquist application device

Abstract

The invention discloses a 2CPFSK (continuous-phase frequency-shift keying) digital-modulation super-Nyquist application device. A baseband signal is output to a DDS (direct digital synthesizer) circuit through a baseband signal receiving circuit, a differential LVPECL (low voltage positive emitter coupling logic) emitter receives a clock signal of a frequency reference source to provide a reference frequency for the DDS circuit, a singlechip is configured with a DDS inner register, the frequency content of a Profile0 register is selected as the output of the DDS circuit when a receiving signal is of low level, and the frequency content of a profile1 register is selected as the output of the DDS circuit when the receiving signal is of high level; and the output of the DDS circuit is subjected to outer frequency element filtering through a band pass filter to obtain a 2CPFSK modulation signal with the required frequency. According to the 2CPFSK digital-modulation super-Nyquist application disclosed by the invention, direct output frequency can reach L wave band or can be higher, bandwidth and transmission velocity are improved, frequency conversion times of a known 2CPFSK signal emitter is reduced, and the size of the emitter is reduced.

Description

technical field [0001] The invention relates to digital signal processing technology, in particular to a device for realizing high-speed 2CPFSK digital modulation based on DDS technology in the super-Nyquist interval. Background technique [0002] At present, in the known UAV data link system, the output of the 2CPFSK digital modulation device is an intermediate frequency of 70MHz, and the lower intermediate frequency limits the bandwidth and transmission rate of the 2CPFSK digital modulation device. The output frequency of the 2CPFSK modulator given in "Application" is 70MHz, and the code rate of the baseband signal is 2.048Mbps. Secondly, due to the low intermediate frequency, the number of up-conversion times of the 2CPFSK signal transmitting device increases, and the volume of the transmitting device increases, which seriously restricts the miniaturization design of the device and limits its application range, especially in the UAV airborne environment with small space. ...

AI Technical Summary

Problems solved by technology

Secondly, due to the low intermediate frequency, the number of up-conversion times of the 2CPFSK signal transmitting device increases, and the volume of the transmitting device increases, which seriously restricts the miniaturization design of the device and limits its application range, especially in the airborne environment of UAVs with small spaces.

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