| |||
| 基准频率信号 | |||
|
frequency reference : 31 phrases in 13 subjects |
| Agriculture | 1 |
| Air defense | 2 |
| Automobiles | 1 |
| Aviation | 1 |
| Electricity | 1 |
| Electronics | 7 |
| Hydroelectric power stations | 1 |
| Mathematics | 1 |
| Oil / petroleum | 1 |
| Piezoelectric crystals | 1 |
| Space | 6 |
| Technology | 3 |
| Telecommunications | 5 |