difference between high pass and low pass filter
Low-pass filter A low-pass filter (LPF) is a filter that passes signals with a frequency lower than a certain cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency. The exact frequency response of the filter depends on the filter design. The filter is sometimes called a high-cut filter, or treble-cut filter in audio applications. A low-pass filter is the complement of a high-pass filter.
Passing lane A passing lane is commonly referred to as a "fast lane" because it is often used for extended periods of time for through traffic or fast traffic. In theory, a passing lane should be used only for passing, thus allowing, even on a road with only two lanes in each direction, motorists to travel at their own pace.