带阻滤波器
维基百科，自由的百科全书
信号处理中的带阻滤波器是指能通过大多数频率分量、但将某些范围的频率分量衰减到极低水平的滤波器，与带通滤波器的概念相对。其中点阻滤波器（notch filter）是一种特殊的带阻滤波器，它的阻带范围极小，有着很高的Q值（Q Factor）。
Typically, the width of the stopband is less than 1 to 2 decades (that is, the highest frequency attenuated is less than 10 to 100 times the lowest frequency attenuated). In the audio band, a notch filter uses high and low frequencies that may be only semitones apart.
Audio example 1: Anti-hum filter
- Low Freq: 59 Hz
- High Freq: 61 Hz
This means that the filter passes all frequencies, except for the range of 59–61 Hz. This would be used to filter out any noise from a 60 Hz power line.
Audio example 2: Anti-presence filter
- Low Freq: 1 kHz
- High Freq: 4 kHz
RF example 1: Non-linearities of power amplifiers For instance, when measuring non-linearities of power amplifiers a very narrow notch filter could be very usefull to avoid the carrier so maximun input power will not be exceeded.
[编辑] 参见
[编辑] 参考文献
- Federal Standard 1037C
- MIL-STD-188
