In this chapter, unless the context otherwise requires:

    "A" band level is the total sound level of all noise as measured with a sound level meter using the "A" weighting network. The unit is the dbA.

    "Ambient noise" means the all-encompassing noise associated with a given environment, usually being a composite of sounds with many sources near and far;

    "Band pressure level" of a sound for a specified frequency band means the sound pressure level for the sound contained within the restricted band;

    "Commercial purpose" includes the use, operation, or maintenance of sound amplifying equipment for the purpose of advertising business, goods, or services, or for attracting the attention of the public to a performance, show, entertainment, exhibition, or event;  

    "Cycle" means the complete sequence of values of a periodic quantity which occurs during a period;

    "Decibel (db)" is a unit of level which denotes the ratio between two quantities which are proportional to power; the number of decibels corresponding to the ratio of two amounts of power is ten times the logarithm to the base ten of this ratio;

    "Emergency work" means work made necessary to restore property to a safe condition following a public calamity, or work required to protect persons or property from an imminent exposure to danger or work by private or public utilities when restoring utility services;

    "Frequency" of a function periodic in time means the reciprocal of the primitive period. The unit is the cycle per unit time and shall be specified;

    "Microbar" is a unit of pressure commonly used in acoustics and is equal to one dyne per square centimeter;   

    "Motor vehicles" include minibikes and gocarts;

    "Noncommercial purpose" is any purpose other than a "commercial purpose" and includes philanthropic, political, patriotic, and charitable purpose;

     "Period" of a periodic quantity means the smallest increment of time for which the function repeats itself;

    "Periodic quantity" means oscillating quantity, the values of which recur for equal increments of time;

    "Person" includes a natural person, firm, association, copartnership, joint venture, corporation, or entity;

    "Sound amplifying equipment" means a device for the amplification of the human voice, music, or other sound. It does not include a standard automobile radio when used and heard only by the occupant of the vehicle nor a warning device on an authorized emergency vehicle or a horn or other warning device used for traffic safety purposes;  

    "Sound analyzer" is a device for measuring the band pressure level or pressure spectrum level of a sound as a function of frequency;

    "Sound level meter" is an instrument including a microphone, an amplifier, an output meter, and frequency weighting networks for the measurement of noise and sound levels in a specified manner;

    "Sound pressure level," in decibels, of a sound means twenty times the logarithm to the base ten of the ratio of the pressure of this sound to the reference pressure, which reference pressure shall be explicitly stated;

    "Sound truck" means a vehicle, regardless of motive power, whether in motion or stationary, having sound amplifying equipment mounted or attached;  

    "Spectrum" of a function of time means a description of its resolution into components, each of a different frequency. (Prior code § 13A-2)