High-pass filter
From Wikinfo
A High-pass filter passes 'high' frequencies fairly well, but attenuates 'low' frequencies. Hence it is useful as a filter to block any unwanted low frequency components of a complex signal whilst passing the higher frequencies.
Of course, the meanings of 'low' and 'high' frequencies are relative.
The simplest high-pass filter consists of a capacitor in series with the signal path in conjunction with a resistor in parallel with the signal path. The resistance times the capacitance (R×C) is the time constant; its reciprocal is the cutoff frequency, at which the output voltage is 70.7% of the input.
Such a circuit would be used in combination with a Tweeter, Loudspeaker.
References
- Adapted from the Wikipedia article, "High-pass_filter" http://en.wikipedia.org/wiki/High-pass_filter, used under the GNU Free Documentation License
