| 21. | a musical note with a frequency of 256 vibrations per second |
| 振动频率为每秒256次的音调
|
| 22. | (radio) frequency that can be heard when converted into sound waves by a loudspeaker |
| 成音频率; 音频
|
| 23. | the frequency of premature births in this region |
| 该地区早产情况的频繁
|
| 24. | amplitude [ frequency ] modulation |
| （无）调幅[调频]；振幅[频率]调制
|
| 25. | frequency departure |
| 频率漂移
|
| 26. | frequency deviation |
| （物）频率漂移
|
| 27. | an auto frequency transformer |
| 音频变压器
|
| 28. | a frequency transformer |
| 变频器
|
| 29. | a high frequency transformer |
| 高频变压器
|
| 30. | with extraordinary frequency |
| 异常频繁地
|