In video mode, noise was a problem too, but in a different sort of way: the mic seemed a bit overboosted, picking up quite a whoosh with the slightest hint of a breeze.
Careful shielding will usually attenuate normal modenoise, and many instruments have internal filtering to reduce the effects of such noise even further.
仔细的屏蔽通常能够衰减串模噪声，很多仪器都有内部的滤波器以进一步降低这种噪声的影响。
3
Balanced detection provides better sensitivity over a single detector because it rejects common modenoise and is more efficient in light usage.