 |
| |||
| 基准频率 | |||
| 基淮频率; 参考频率 | |||
|
frequency reference : 28 phrases in 12 subjects |
| Agriculture | 1 |
| Air defense | 2 |
| Automobiles | 1 |
| Aviation | 1 |
| Electronics | 7 |
| Hydroelectric power stations | 1 |
| Mathematics | 1 |
| Oil / petroleum | 1 |
| Piezoelectric crystals | 1 |
| Space | 6 |
| Technology | 2 |
| Telecommunications | 4 |
The server is undergoing maintenance and the site is working in read-only mode. Please check back later.">Add | The server is undergoing maintenance and the site is working in read-only mode. Please check back later.">Report an error
| Get short URL | Language Selection Tips