Title:
ON-VEHICLE ACOUSTIC EQUIPMENT
Document Type and Number:
Japanese Patent JP3269832
Kind Code:
B2
Abstract:
PURPOSE: To attain the automatic sound volume adjustment regardless of a reproduction sound level corresponding to external noise by detecting the noise level when the level of a music signal reproduced in a cabin is small.
CONSTITUTION: A voltage level detector 11 detects an voltage comparator 13 compares the level with the level of a DC voltage source 12. The output voltage of the voltage comparator 13 is inputted to the control signal terminal of a hold circuit 14. On the other hand, an output signal from a microphone 6 is given to a voltage level detector 7, which detects a noise level in the cabin and the level is inputted to the hold circuit 14. When an H level is inputted to the control signal terminal of the hold circuit 14, the noise level inputted at that point of time is outputted and when an L level is inputted to the control signal terminal, the noise level at the H level is kept and outputted. The output of the hold circuit 14 is given to the control signal terminal of a VCA2 through a time constant circuit 15 to control the gain of the VCA2. Since the VCA2 receives the output signal of the audio signal source 1, sound volume is automatically adjusted corresponding to the noise.
Inventors:
Masahiro Tsujishita
Masahiro Hibino
Masahiro Hibino
Application Number:
JP28116191A
Publication Date:
April 02, 2002
Filing Date:
October 28, 1991
Export Citation:
Assignee:
Mitsubishi Electric Corporation
International Classes:
H03G3/32; (IPC1-7): H03G3/32
Domestic Patent References:
| JP49120504A | ||||
| JP49120505A | ||||
| JP5751319U |
Attorney, Agent or Firm:
Minoru Maeda