Title:
ALARM TONE GENERATOR
Document Type and Number:
Japanese Patent JP3191897
Kind Code:
B2
Abstract:
PURPOSE: To sharpen a directivity of a found wave in front of a vehicle body by controlling a phase of input to each speaker so as to maximize a time average power of sound waves in front of the vehicle body depending on the drive speed.
CONSTITUTION: Speakers are arranged with deviation in the forward/backward direction of a vehicle body 2, a sine wave is used for an alarm signal and number of speakers is selected to be e.g. 4. Then an output of a signal generating section 4 is given to a speaker S1 directly in the frontmost position and to speakers S2-S4 through a phase shifter 5, and the phase shifter 5 controls the phase of the alarm signal for each of the speakers S2-S4 based on the phase of the input to the speaker S1. That is, the phase shifter 5 controls the phase of the alarm signal fed from the signal generating section 4 so as to miximize the time average power of the sound wave in front of the vehicle body through the generation of the signal deviated respectively in response to the drive speed for each of the speakers S2-S4 except the speaker S1 of the frontmost position (or final position) and the signal is inputted to each of the speakers S2-S4.
Inventors:
Takehiro Moriya
Application Number:
JP1830694A
Publication Date:
July 23, 2001
Filing Date:
February 15, 1994
Export Citation:
Assignee:
Nippon Telegraph and Telephone Corporation
International Classes:
H04R1/40; B60R11/02; H04R3/12; (IPC1-7): H04R3/12; B60R11/02; H04R1/40
Domestic Patent References:
| JP6457899A | ||||
| JP62117099A |
Attorney, Agent or Firm:
Suguru Kusano