Silencing apparatus operable to reduce vehicle noise at a telephone

A silencing apparatus comprising:

• a noise reduction signal generator for generating noise cancellation signals which reduce noises from a vehicle at a telephone;
• a first noise sensor for measuring noises from the vehicle to be reduced by said noise reduction signal generator;
• a second sensor for detecting the presence or absence of the vehicle when it is sufficiently close to the telephone that noise produced by the vehicle can be heard at the telephone, and
• control circuitry comprising:
• first means responsive to the detection of the presence of the vehicle by the second sensor,
• second means responsive to the noise from the vehicle measured by the first sensor becoming greater than a first threshold level,
• third means, responsive to the first and second means, for selectively activating said noise reduction signal generator in response to the noise from the vehicle measured by said first sensor becoming greater than the first threshold level and to the detection of the presence of the vehicle by the second sensor,
• fourth means responsive to the noise measured by the first sensor becoming smaller than a second threshold level, and
• fifth means, responsive to the fourth means, for deactivating said noise reduction signal generator in response to the noise measured by said noise sensor becoming smaller than the second threshold level.

A silencing apparatus, comprising:

• a first sensor for detecting the presence of a vehicle that is sufficiently close to a telephone that noise produced by the vehicle can be heard at the telephone,
• a noise reduction signal generator responsive to said sensor for providing a noise reduction signal which reduces the noise produced at the telephone by the vehicle if the presence of the vehicle is detected by said sensor, and
• a second sensor for detecting noise from the vehicle,
• control circuitry for selectively activating said noise reduction signal generator according to the noise measured by said second sensor and according to the detection of the presence of the vehicle by the first sensor, wherein said control circuitry is also for deactivating said noise reduction signal generator according to the noise measured by said noise sensor, and wherein deactivating said noise reduction signal generator causes said noise reduction signal generator to cease generating any noise reduction signals.

A silencing method, comprising:

• measuring acoustic characteristics of a first noise which is generated by a first of a plurality of different vehicles, when the first vehicle is moving toward a listener;
• detecting physical characteristics of the first vehicle as it is moving toward the listener;
• deciding that the first vehicle belongs to a first of a plurality of predetermined vehicle types, according to the physical characteristics detected by the step of detecting characteristics of the first vehicle;
• providing a first noise reduction signal which reduces the first noise reaching the listener, in response to the decision that the vehicle belongs to the first vehicle type;
• measuring acoustic characteristics of a second noise which is generated by a second of the plurality of vehicles, when the second vehicle is moving toward the listener;
• detecting physical characteristics of the second vehicle as it is moving toward the listener;
• deciding that the second vehicle belongs to a second of the plurality of vehicle types, according to the physical characteristics detected by the step of detecting characteristics of the second vehicle;
• and
• providing a second noise reduction signal, different from the first noise reduction signal, which reduces the second noise reaching the listener, in response to the decision that the vehicle belongs to the second vehicle type.