Common use of Measurement procedure Clause in Contracts

Measurement procedure. The frequency characteristics of the sound shall be measured together with an input signal to the external sound generation system corresponding to the reference vehicle speed. The sound output of the system shall be measured as follows: Record at least 5 seconds of the sound at a constant vehicle speed. Using a Xxxxxxx window, calculate the autopower of the signal with a frequency resolution of at least 1 Hz using at least 66.6% overlapp averages from the 5 second time signal The frequencies, fi, speed, of the external sound generation system signal shall be measured and recorded. The corresponding vehicle speeds, fi,speed and fi,ref shall be measured and recorded. Calculate del_f, the frequency shift of the external sound generation system signal according to equation (1): del_f = {[(fi,speed - fi,ref)/(vtest – vref)]/fi,ref} · 100 (1) where fi,speed is the frequency at a given speed value; fi,ref is the frequency at the reference speed value; vtest is the vehicle velocity, actual or simulated, corresponding to the frequency fi,speed; vref is the vehicle velocity, actual or simulated, corresponding to the frequency fi,ref; This equation is only valid when the actual vehicle speed, vtest, is higher than the reference vehicle speed, vref. Results shall be reported using Table 3. Table 0A3 — Vehicle speed for measurement to determine frequency shift Target speed Actual Speed (km/h) Frequency, fi, speed (Hz) Frequency Shift Reference vehicle speed Not Applicable 10 km/h 15 km/h 20 km/h NOTE The reference speed should be 5 km/h unless other speeds are desired. ISO comment : If we are going to choose the reference speed as 5, need to change sentence: " The reference speed shall be 5 km/h Figure 1a and 1b