Patent ID: 9131291
Filing Date: 2015-09-08
Classification: G05B,G06F,H04R

Abstract:
1. An audio recording and playback device, capable of recording and playing back audio, comprising: an audio input section for converting audio input during an audio recording operation into an electrical audio signal; a power feed section for carrying out power feed to the audio input section by means of a balanced transmission line; an amplifier section for amplifying the audio signal; a boost section for generating a power feed voltage to be applied to the balanced transmission line and outputting to the power feed section; an output current detection section for detecting output current output by the boost section to the power feed section; an output voltage changing section for carrying out control to vary the output voltage of the boost section; and a control section for controlling power feed voltage of the power feed section by controlling the power feed section and the output voltage changing section based on output of the output current detection section, wherein the control section controls the output voltage changing section, based on output of the output current detection section, to bring the output voltage of the boost section to a specified target voltage by increasing or reducing by a specified voltage every fixed interval a specified number of times, and outputting to the power feed section, and wherein the control section, when output of the output current detection section, in a state where a first target voltage has been set, is smaller than a specified value, sets to a second target voltage that is lower than the first target voltage.