倍频程
倍频程(英語:),又称为倍频带,是振动与噪音分析中将整个频谱划分为若干频带的方法,每个频带的上限频率是下限频率的两倍。类似地,1/3倍频程(one-third octave band)指每个频带的上限频率与下限频率之比是2的立方根。
倍频程
计算
假设每个频带的中心频率为,该频带的上限频率与下限频率可由下式计算:
- ,
其中为下限频率,为上限频率。
名称
| 频带序号 | 标称频率[1] | 计算频率 | A计权修正 |
|---|---|---|---|
| -1 | 16 Hz | 15.625 Hz | |
| 0 | 31.5 Hz | 31.250 Hz | -39.4 dB |
| 1 | 63 Hz | 62.500 Hz | -26.2 dB |
| 2 | 125 Hz | 125.000 Hz | -16.1 dB |
| 3 | 250 Hz | 250.000 Hz | -8.6 dB |
| 4 | 500 Hz | 500.000 Hz | -3.2 dB |
| 5 | 1k Hz | 1000.000 Hz | 0 dB |
| 6 | 2k Hz | 2000.000 Hz | 1.2 dB |
| 7 | 4k Hz | 4000.000 Hz | 1 dB |
| 8 | 8k Hz | 8000.000 Hz | -1.1 dB |
| 9 | 16k Hz | 16000.000 Hz | -6.6 dB |
1/3倍频程
以2为基数
%% Calculate Third Octave Bands (base 2) in Matlab
fcentre = 10^3 * (2 .^ ([-18:13]/3))
fd = 2^(1/6);
fupper = fcentre * fd
flower = fcentre / fd
为10为基数
%% Calculate Third Octave Bands (base 10) in Matlab
fcentre = 10.^(0.1.*[12:43])
fd = 10^0.05;
fupper = fcentre * fd
flower = fcentre / fd
名称
| 频带序号 | 标称频率 | 计算频率(以2为基数) | 计算频率(以10为基数) |
|---|---|---|---|
| 1 | 16 Hz | 15.625 Hz | 15.849 Hz |
| 2 | 20 Hz | 19.686 Hz | 19.953 Hz |
| 3 | 25 Hz | 24.803 Hz | 25.119 Hz |
| 4 | 31.5 Hz | 31.250 Hz | 31.623 Hz |
| 5 | 40 Hz | 39.373 Hz | 39.811 Hz |
| 6 | 50 Hz | 49.606 Hz | 50.119 Hz |
| 7 | 63 Hz | 62.500 Hz | 63.096 Hz |
| 8 | 80 Hz | 78.745 Hz | 79.433 Hz |
| 9 | 100 Hz | 99.213 Hz | 100 Hz |
| 10 | 125 Hz | 125.000 Hz | 125.89 Hz |
| 11 | 160 Hz | 157.490 Hz | 158.49 Hz |
| 12 | 200 Hz | 198.425 Hz | 199.53 Hz |
| 13 | 250 Hz | 250.000 Hz | 251.19 Hz |
| 14 | 315 Hz | 314.980 Hz | 316.23 Hz |
| 15 | 400 Hz | 396.850 Hz | 398.11 Hz |
| 16 | 500 Hz | 500.000 Hz | 501.19 Hz |
| 17 | 630 Hz | 629.961 Hz | 630.96 Hz |
| 18 | 800 Hz | 793.701 Hz | 794.33 Hz |
| 19 | 1 kHz | 1000.000 Hz | 1000 Hz |
| 20 | 1.25 kHz | 1259.921 Hz | 1258.9 Hz |
| 21 | 1.6 kHz | 1587.401 Hz | 1584.9 Hz |
| 22 | 2 kHz | 2000.000 Hz | 1995.3 Hz |
| 23 | 2.5 kHz | 2519.842 Hz | 2511.9 Hz |
| 24 | 3.150 kHz | 3174.802 Hz | 3162.3 Hz |
| 25 | 4 kHz | 4000.000 Hz | 3981.1 Hz |
| 26 | 5 kHz | 5039.684 Hz | 5011.9 Hz |
| 27 | 6.3 kHz | 6349.604 Hz | 6309.6 Hz |
| 28 | 8 kHz | 8000.000 Hz | 7943.3 Hz |
| 29 | 10 kHz | 10079.368 Hz | 10 kHz |
| 30 | 12.5 kHz | 12699.208 Hz | 12.589 kHz |
| 31 | 16 kHz | 16000.000 Hz | 15.849 kHz |
| 32 | 20 kHz | 20158.737 Hz | 19.953 kHz |
参考文献
- (PDF). [7 March 2018]. (原始内容存档 (PDF)于2020-10-25).
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