Radiation Emitting Devices Regulations — 1
1 In this Part and in item 13 of Schedule I, amplitude modulated wave means a wave in which the ratio of the temporal maximum pressure amplitude to the root-mean square pressure amplitude, each spatially averaged over the effective radiating surface, is greater than 1.05; ( onde modulée en amplitude ) applicator means the part of the ultrasound therapy device designed to transmit ultrasonic power from the transducer to a patient and includes the transducer and any associated housing; ( applicateur ) continuous wave means a wave in which the ratio of the temporal maximum pressure amplitude to the root-mean square pressure amplitude, each spatially averaged over the effective radiating surface, is less than or equal to 1.05; ( onde entretenue ) control panel means that portion of the external surface of the housing on which the user controls are mounted; ( tableau de commande ) effective intensity [Revoked, SOR/84-930, s. 2] effective radiating area means the area of the effective radiating surface that encompasses all points at which the ultrasonic intensity is equal to or greater than five per cent of the maximum spatial ultrasonic intensity at the effective radiating surface, expressed in square centimetres (cm 2 ); ( aire émettrice utile ) effective radiating surface means the surface covering all points that are 5 mm from the applicator face; ( surface émettrice utile ) effective ultrasonic intensity , with respect to ultrasonic power, means (a) in the case of a focussing applicator, the quotient obtained by dividing the amount of the ultrasonic power by the amount of the focal area, and (b) in any other case, the quotient obtained by dividing the amount of the ultrasonic power by the amount of the effective radiating area; ( intensité ultrasonore utile ) focal area means the area of the focal surface expressed in square centimetres (cm 2 ); ( aire focale ) focal length in respect of a focussing applicator, means the distance in centimetres between (a) that point of the effective radiating surface the coordinates of which are the mean values of the coordinates of the points of that surface, and (b) that point of the focal surface the coordinates of which are the mean values of the coordinates of the points of that surface; ( longueur focale ) focal surface in respect of a focussing applicator, means the beam cross-section with the smallest area; ( surface focale ) focussing applicator means an applicator in which the quotient of the area of the surface having the smallest area, in any plane consisting of the points at which the ultrasonic intensity is greater than five per cent of the maximum intensity in that plane, and the effective radiating area is less than one-half; ( applicateur focalisant ) housing means a structure that encloses (a) that portion of a fully assembled ultrasound therapy device that supplies the electrical energy to the applicator, and (b) the electrical circuitry of the device; ( logement ) maximum intensity [Revoked, SOR/84-930, s. 2] pressure amplitude means the instantaneous value of the modulating waveform in the following equation: p(t)=p 1 (t)p 2 (t) where p(t) is the instantaneous pressure, p 1 (t) is the modulating wave form, p 2 (t) is the relative amplitude of the carrier wave normalized to a peak height of one, p(t), p 1 (t) and p 2 (t) are periodic functions of time, t, at any point in space, and the period of p 1 (t) is greater than the period p 2 (t); ( amplitude de pression ) pulse duration means a time interval, expressed in seconds, beginning at the first time the pressure amplitude exceeds the value that equals the sum of the minimum pressure amplitude and 10 per cent of the difference between the maximum and minimum pressure amplitudes and ending at the last time the pressure amplitude returns to that value; ( durée des impulsions ) pulse repetition rate means the repetition frequency of the wave shape that modulates the ultrasonic radiation carrier wave expressed in pulses per sec