Patent ID: 9648415
Date: 2017-05-09
CPC Classifications: B60C,B60Q,H04R

Claim:
1. A vehicle approach warning apparatus outputting a warning sound signal, and causing a speaker to output a warning sound according to the warning sound signal, and notifying a pedestrian around a vehicle that the vehicle approaches the pedestrian, the vehicle approach warning apparatus comprising: a memory that stores a first signal generation portion configured to generate the PWM signal of the low frequency component from the first sound source data, and a second signal generation portion configured to generate the PWM signal of the high frequency component from the second sound source data, the second signal generation portion being different from the first signal generation portion; a processor; a signal synthesizing portion; and an amplifier, the processor is configured to the amplifier is configured to receive the synthesized warning sound signal from the signal synthesizing portion, to amplify the synthesized warning sound signal by a predetermined amplification factor to generate an amplified warning sound signal, and to output the amplified warning sound signal to the speaker, wherein: the whole sound pressure level of the warning sound generated by the speaker according to the amplified warning sound signal is maintained in changing the level of the PWM signal of the low frequency component and the level of the PWM signal of the high frequency component when the vehicle speed changes; and when the processor adjusts, in the level adjustment portion, the level of the PWM signal of the low frequency component and the level of the PWM signal of the high frequency component, the processor refers to the first table which specifies the first factor corresponding to the duty ratio of the PWM signal of the low frequency component and the second table stored in the memory which specifies the second factor corresponding to the duty ratio of the PWM signal of the high frequency components, and adjusts the level of the PWM signal of the low frequency component and the level of the PWM signal of the high frequency component respectively while using the first factor specified by the first table and the second factor specified by the second table.