GB/T 38694-2020Requirements and test methods of alert for vehicle turnning right (English PDF)

3.1 Alert for Vehicle Turning Right

Alert for vehicle turning right refers to the sound that a vehicle emits to the right area when turning right, which can prompt other road users.

NOTE: alert for vehicle turning right is abbreviated as alert in this Standard.

3.2 Alert Device for Vehicle Turning Right

Alert device for vehicle turning right refers to a device installed in a specified area of the vehicle and can emit a prompt tone as required.

NOTE: alert device for vehicle turning right is abbreviated as alert device in this Standard.

5.1 Alert Device Test

5.1.1 Test conditions

5.1.1.1 Measurement site

Anechoic room or semi-anechoic room; the background noise is <= 40 dB(A). Except for special requirements, the ambient temperature of the test is 23 °C ± 5 °C.

5.1.1.2 Measurement instrument

When carrying out 1/3 octave measurement, the measurement instrument shall comply with the stipulations of Level-1 filter in GB/T 3241-2010. The used sound level meter or other equivalent measurement instruments shall comply with the stipulations of Level-1 instrument in GB/T 3785.1-2010. During the measurement, the "A" frequency weighting characteristics and "F" time weighting characteristics described in GB/T 3785.1-2010 shall be used. When a system that can periodically monitor the A- weighted sound level is used, the time interval of the readings shall be not greater than 30 ms. In terms of buzzer voice combination alert, the measurement instrument shall be able to respectively measure the sound pressure level of the buzzer and the voice voice combination alert. Respectively measure the sound pressure level of the buzzer alert and the voice alert. For each alert, measure three times. The difference among the measurement results shall not exceed 2 dB(A). Take the average of the three measurement results respectively as the final measurement result of the buzzer alert and voice alert; compare them and the result shall comply with the stipulations of 4.2.2.

5.1.4 Frequency rate and frequency measurement

5.1.4.1 Under the conditions specified in 5.1.1, measure the frequency rate of the buzzer. The result shall comply with the stipulations of 4.2.1.

5.1.4.2 Under the conditions specified in 5.1.1, measure the frequency of the alert; the total duration of the measurement shall be not less than 3 min. If the last cycle is an incomplete cycle, it shall also be counted as one cycle. The result shall comply with the stipulations of 4.2.1.

5.2 Complete-vehicle Alert Test

5.2.1 Test conditions

5.2.1.1 Measurement site

Flat open ground composed of concrete, dense asphalt or similar hard materials without obvious pores. Avoid conducting the measurement on snowfield, haystacks, loose soil or other grounds with sound absorption characteristics. Within 10 m from the sound level meter of the vehicle to be tested, there shall be no large reflectors, such as: vehicles, buildings, billboards, trees, parallel walls and people, etc.

5.2.1.2 Meteorological conditions

The weather shall manifest NO snow, rain or fog. The wind speed (including gusts) shall be not greater than 5 m/s. When the wind speed exceeds 2 m/s, it is recommended that the sound level meter shall use a windshield. During the test, the ambient temperature range is -10 °C ~ 50 °C; it shall also comply with the stipulations of 6.3.1 in GB/T 3785.1-2010.

5.2.1.3 Background noise

During the measurement, the background noise (A-weighted sound pressure level) is at least 10 dB(A) lower than the alert being measured.

5.2.1.4 Measurement instrument

The used sound level meter or other equivalent measurement instruments, including the windshields, shall comply with the stipulations of Level-1 instruments in GB/T 3785.1-2010. During the measurement, the "A" frequency weighting characteristics and "F" time weighting characteristics described in GB/T 3785.1-2010 shall be used. […]