Title:
RECEPTION SIGNAL FREQUENCY CHARACTERISTIC CORRECTION SYSTEM AND HANDSET USED FOR THE SYSTEM
Document Type and Number:
Japanese Patent JP3231949
Kind Code:
B2
Abstract:
PURPOSE: To correct the frequency characteristics of reception signals while monitoring the frequency characteristics of actual sound to ear by supplying synthetic output for which respective frequency band reception signal levels are controlled to the receiver of a handset.
CONSTITUTION: A microphone 3 for detecting the actual sound to ear is mounted to the recessed surface 2 of the earpiece of this handset 1, the back surface of the microphone 3 is completely sealed and the microphone 3 detects only sound on the front surface of the recessed surface 2 of the earpiece of the handset 1. The detection signal level of respective frequency bands for which the signals of the reception input are divided into plural is compared with the reception signal level of the respective frequency bands for which the signals of the output point of a pickup amplifier 7 for amplifying the output of the microphone 3 which detects the actual sound to ear are divided into plural. By the difference, the frequency characteristics are corrected in a frequency correction circuit 6 and the frequency of actual ear reception sound is reproduced so as to be flat. Thus, even though the earpiece of the handset is lightly held to an ear or strongly held to the ear, flat and easily listenable reception sound quality in a desired band is obtained at all times.
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Inventors:
Yoshimasa Kamozu
Yasushi Hatakeyama
Kazuhiko Sagara
Yasushi Hatakeyama
Kazuhiko Sagara
Application Number:
JP17313894A
Publication Date:
November 26, 2001
Filing Date:
July 04, 1994
Export Citation:
Assignee:
Iwasaki Tsushinki Co., Ltd.
Nippon Telegraph and Telephone Corporation
Nippon Telegraph and Telephone Corporation
International Classes:
H04M1/00; (IPC1-7): H04M1/00
Domestic Patent References:
| JP675583A | ||||
| JP5284199A | ||||
| JP3195296A | ||||
| JP5122121A | ||||
| JP1152823A | ||||
| JP3117950A | ||||
| JP60214113A | ||||
| JP4135053U | ||||
| JP1135847U |
Attorney, Agent or Firm:
Manabu Otsuka