Measuring chain for measuring the noise of road vehicles according to the SPB method
The SPB (Statistical Pass-By Method) measuring equipment is a measuring chain of several devices connected in a system. The measuring chain includes a microphone, a modular precision sound analyzer, 2 photocells for vehicle speed measurements, a laptop computer, a microcontroller, and a humidity and temperature meter. It is intended for measuring the maximum noise level of passing road vehicles and determining the SPB index, which defines driving surfaces according to the noise they cause.
The measurement method is carried out in accordance with the SIST EN ISO 11819-1 standard. It determines the influence of car tires rolling on road surfaces on the emission of road traffic noise into the environment. The modular precision sound analyzer detects the maximum noise levels of passing vehicles via a microphone standing 7.5 m from the center of the considered driving lane on the test field. Photocells record the passage of vehicles at the measurement point. The speed is determined from the difference in the registration times of each photocell and from the mutual distance between the positions of the photocells, and at the same time the category of the individual vehicle is entered into the computer. After computer processing of the data, a regression curve of the maximum noise levels depending on the speed of the vehicles is determined depending on the type of vehicle.