公开(公告)号：US20230139520A1

公开(公告)日：2023-05-04

申请号：US17914378

申请日：2020-03-30

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Masahiro FUKUI ,  Kazunori KOBAYASHI

IPC: G10K11/178 ,  H04R1/10 ,  H04R1/02

Abstract: A technology is provided that reduces noise heard when a user sits in a seat of an aircraft, without using earphones or headphones. A sound system includes: a control system that generates a control signal for canceling noise in a place close to a head of a user using a seat of an aircraft, from a signal of the noise (noise signal); and a noise-cancellation speaker system including speaker units that emit sound based on the control signal (first noise-cancellation speaker unit, . . . , M-th noise-cancellation speaker unit), the noise-cancellation speaker system being installed at the place close to the head of the user using the seat, wherein assuming that a direction in which the m-th noise-cancellation speaker unit faces the user is an m-th noise-cancellation user direction, the m-th noise-cancellation speaker unit is disposed such that sound emitted from the m-th noise-cancellation speaker unit in the m-th noise-cancellation user direction is canceled in a place other than the place close to the head of the user using the seat, due to bending around of sound emitted from the m-th noise-cancellation speaker unit in an opposite direction to the m-th noise-cancellation user direction.

公开(公告)号：US20200090665A1

公开(公告)日：2020-03-19

申请号：US16687176

申请日：2019-11-18

Applicant: Nippon Telegraph and Telephone Corporation

Inventor： Takehiro MORIYA ,  Noboru HARADA ,  Yutaka KAMAMOTO ,  Yusuke HIWASAKI ,  Masahiro FUKUI

IPC: G10L19/005 ,  G10L19/032 ,  G10L19/24 ,  G10L19/008 ,  G10L21/038 ,  G10L19/16

Abstract: In encoding, a frequency-domain sample sequence derived from an acoustic signal is divided by a weighted envelope and is then divided by a gain, the result obtained is quantized, and each sample is variable-length encoded. The error between the sample before quantization and the sample after quantization is quantized with information saved in this variable-length encoding. This quantization is performed under a rule that specifies, according to the number of saved bits, samples whose errors are to be quantized. In decoding, variable-length codes in an input sequence of codes are decoded to obtain a frequency-domain sample sequence; an error signal is further decoded under a rule that depends on the number of bits of the variable-length codes; and from the obtained sample sequence, the original sample sequence is obtained according to supplementary information.