Abstract: An adjustable seat backrest structure, including a support, an adjusting component, and backrest plates; an adjusting groove extending along an up-down direction is formed at a middle part of the support; a front side of the adjusting component is connected to the backrest plates; an adjusting part is arranged on a rear side of the adjusting component; a left end and a right end of the adjusting part engage with a left side edge and a right side edge of the adjusting groove respectively so that the adjusting part is slidable up and down in the adjusting groove and being capable to be fixed at any position with respect to the adjusting groove, but not capable of moving front and back with respect to the adjusting groove.

Abstract: Disclosed are a method and apparatus for improving a signal-to-noise ratio of a microphone signal. The method includes: selecting a target microphone to be improved as a first microphone, and selecting a microphone whose signal-to-noise ratio is greater than a signal-to-noise ratio of the first microphone and exceeds a preset first threshold as a second microphone; and adding, by an adder, a voice signal of the first microphone and a voice signal of the second microphone in a case that a same voice signal is inputted, to obtain a first microphone signal whose signal-to-noise ratio has been improved.

Abstract: Disclosed are a method and apparatus for improving a signal-to-noise ratio of a microphone signal. The method includes: selecting a target microphone to be improved as a first microphone, and selecting a microphone whose signal-to-noise ratio is greater than a signal-to-noise ratio of the first microphone and exceeds a preset first threshold as a second microphone; and adding, by an adder, a voice signal of the first microphone and a voice signal of the second microphone in a case that a same voice signal is inputted, to obtain a first microphone signal whose signal-to-noise ratio has been improved.