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 includes a voltage-controlled oscillator, a phase detector, a loop filter and an adder. The voltage-controlled oscillator is used to output the Chirp signal, and the oscillation frequency of the voltage-controlled oscillator can be adjusted to control the phase or frequency of the output signal. The phase detector receives the first input signal and compares the phases of the first input signal with the voltage-controlled oscillator output signal to generate the first signal. The loop filter filters out the high-frequency signal and the noise signal on the first signal to generate the second signal. The adder receives the second input signal and superimposes 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. The second input signal is a triangular wave signal, including a plurality of triangular wave symbols with the same frequency waveform, and the starting and ending frequencies of the symbols are the same. The transition time for generating the Chirp signal in the present invention is shorter, and 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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