Tuning method of automatic tuning circuit, automatic tuning circuit and signal transmitting device

Abstract

This application relates to a tuning method of an automatic tuning circuit, an automatic tuning circuit and a signal transmitting device. The tuning method detects and converts the voltage signal at both ends of the balun tuning capacitor array into a corresponding first DC voltage signal. The bit controller is initialized to the preset capacitance control value, and the reference voltage adjustment circuit is initialized and trained to obtain the corresponding reference voltage. By continuously changing the value of the capacitance level controller and the size of the reference voltage output by the reference voltage adjustment circuit, further Through the voltage comparator, the first DC voltage signal is continuously compared with the reference voltage output by the reference voltage adjustment circuit to output the corresponding first voltage comparison result, and then the value of the above-mentioned capacitance controller and the reference voltage are compared according to the first voltage comparison result The size of the reference voltage output by the circuit is adjusted to perform loop feedback adjustment, and finally the balun circuit is always kept in a resonant state, and the transmission efficiency of signal power is improved.

Description

technical field [0001] The present application relates to the technical field of signal transmission, and in particular to an automatic tuning circuit tuning method, an automatic tuning circuit and a signal transmitting device. Background technique [0002] At present, with the development of wireless earphones, the requirements for wireless signal transmission performance indicators are gradually increasing, especially for the performance indicators of transmission power. [0003] Among them, during the transmission of wireless signals, the digital baseband signal (two intermediate frequency signals that are mutually orthogonal) is usually modulated to a high frequency signal (usually 2.4G frequency band), and then the high frequency signal is differentially passed through a balun circuit Turn to single-ended processing, and finally generate antenna radio frequency signals through the antenna for transmission. [0004] Among them, since the balun circuit usually includes a...

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Problems solved by technology

[0005] However, for the above-mentioned balun circuit and tuning capacitor and other components, there are usually disadvantages of the uncertainty of the prototype and the uncertainty of the transmitting antenna during mass production, which in turn leads to changes in the resonant frequency of the above-mentioned resonant capacitor. Therefore, If a fixed tuning capacitor is connected according to the traditional method, it is difficult to ensure that the balun circuit is in the state of maximum power transmission, resulting in low signal power transmission efficiency of the balun circuit

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