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| International Standard Category: Acoustic measurements and noise abatement in general |
GB/T 4854.4-1999 Acoustics-Reference zero for the calibration of audiometric equipment-Part 4：Reference levels for narrow-band masking noise
声学 校准测听设备的基准零级 第4部分：窄带掩蔽噪声的基准级 ;
| Category No.: | 17.140.01 | Valid Status: | valid |
| Issued Organization: | State Quality and Technology Supervision Bureau | Issued Date: | 1999-03-08 |
| Implemented Date: | 1999-9-1 | Abolished Date: | |
| Superseded Standard.: | Superseded Date: |
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