Abstract: A device including an inverter circuit, a hysteresis control circuit, and a high-side input level shifter. The inverter circuit having an output and including at least two series connected PMOS transistors connected, at the output, in series to at least two series connected NMOS transistors. The hysteresis control circuit coupled to the output to provide feedback to the at least two series connected PMOS transistors and to the at least two series connected NMOS transistors. The high-side input level shifter connected to gates of the at least two PMOS transistors and configured to shift a low level of an input signal to a higher level and provide the higher level to one or more of the gates of the at least two PMOS transistors.

Abstract: A power tool has a clamping mechanism having an assembling mount and two clamping blocks. The assembling mount has a main body, a receiving recess defined in the main body, two first limiting troughs communicating with the receiving recess, and a through hole defined through a bottom of the receiving recess. The two clamping blocks are disposed in the receiving recess. Each one of the two clamping blocks has an abutting face corresponding to the bottom of the receiving recess in shape and facing to the bottom of the receiving recess. One of the two clamping blocks has two limiting ribs respectively inserted in the two first limiting troughs. The two limiting ribs respectively guided and blocked by the two first limiting troughs to prevent the clamping block from sliding downward along the bottom of the receiving recess.

Abstract: A method using an may microphone to cancel echo applies to a sound receiving system and comprises steps: an array microphone receiving a sound source and outputting a plurality of analog acoustic signals formed from the sound source; an A/D converter converting the analog acoustic signals into a plurality of digital acoustic signals; a digital signal processor respectively using an adaptive beamforming process and a blocking matrix filtering process to convert the digital acoustic signals into a primary acoustic signal and at least one noise signal; and the digital signal processor using a multiple-input cancelling process to subtract the noise signal from the primary acoustic signal to obtain an acoustic signal where the echo has been cancelled. Thereby, the present invention can eliminate the systematic errors of the array microphone of the sound receiving system and improves the robustness of the acoustic signal.

Abstract: A method using an may microphone to cancel echo applies to a sound receiving system and comprises steps: an array microphone receiving a sound source and outputting a plurality of analog acoustic signals formed from the sound source; an A/D converter converting the analog acoustic signals into a plurality of digital acoustic signals; a digital signal processor respectively using an adaptive beamforming process and a blocking matrix filtering process to convert the digital acoustic signals into a primary acoustic signal and at least one noise signal; and the digital signal processor using a multiple-input cancelling process to subtract the noise signal from the primary acoustic signal to obtain an acoustic signal where the echo has been cancelled. Thereby, the present invention can eliminate the systematic errors of the array microphone of the sound receiving system and improves the robustness of the acoustic signal.