Chirp signal generator, Chirp communication system and method for generating Chirp signal

Abstract

The invention discloses a Chirp signal generator, a Chirp communication system and a method for generating a Chirp signal. The Chirp signal generator comprises a voltage-controlled oscillator, a phasediscriminator, a loop filter and an adder. The voltage-controlled oscillator is used for outputting a Chirp signal, and the oscillation frequency of the voltage-controlled oscillator can be adjustedso as to control the phase or frequency of an output signal of the voltage-controlled oscillator. The phase discriminator receives the first input signal and compares phases of the first input signaland the output signal of the voltage-controlled oscillator, and generates a first signal. The loop filter filters a high-frequency signal and a noise signal from the first signal to generate a secondsignal. And the adder receives the second input signal and superposes the second signal and the second input signal to generate a third signal, and the third signal controls the voltage-controlled oscillator to adjust the oscillation frequency. Wherein the second input signal is a triangular wave signal and comprises a plurality of triangular wave symbols with the same frequency waveform, and thesymbol starting point and the symbol ending point are the same in frequency. The transition time for generating the Chirp signal is shorter, and the method can be applied to high-speed communication.

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to a Chirp signal generator, a Chirp communication system and a method for generating Chirp signals. Background technique [0002] Chirp signal is a spread-spectrum signal that exhibits the characteristics of linear frequency modulation, and the signal frequency changes linearly with time, also called linear frequency sweep signal. It has been widely used in radar detection, underwater acoustic communication, laser communication, ultra-wideband communication and LORA communication. [0003] In the communication system, the frequency scanning characteristics of the Chirp signal are used, such as the frequency scanning speed, the frequency scanning direction, etc. to represent the data symbols of the communication, so as to achieve the effect of frequency spreading. This communication method using the Chirp signal for frequency spreading is called Chirp spreading frequ...

AI Technical Summary

Problems solved by technology

Figure 7 Indicates that there are 3 consecutive symbols, and the information bits sent are all 1. At this time, frequency hopping occurs between two symbols, but the phase-locked loop needs Δt time to track in place. During this period, the receiving end cannot demodulate correctly, reducing communication The demodulation performance of the system, if the proportion of this transition time is too large in the case of high symbol rate, it will lead to the failure to correctly demodulate the signal and restore the original data

[0011] Therefore, the existing chirp modulation scheme using phase-locked loop plus VCO control, due to the frequency hopping at the symbol boundary, the transition time is long, so it is impossible to achieve a high code rate chirp modulation communication system

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