Ylipäästösuodin

Ylipäästösuodin, or high-pass filter in English, is an electronic circuit that allows signals with a frequency higher than a certain cutoff frequency to pass through, while attenuating signals with frequencies lower than the cutoff frequency. This means it blocks low frequencies and lets high frequencies through. The cutoff frequency is the point at which the filter's output power is reduced by half, or by 3 decibels.

High-pass filters are used in a wide variety of applications. In audio systems, they are often used to remove low-frequency noise, such as rumble from turntables or hum from power supplies. They can also be used to isolate specific frequency bands in signal processing. For instance, in communication systems, a high-pass filter might be used to remove unwanted low-frequency interference.

The design of a high-pass filter can vary depending on the desired performance characteristics. Simple passive filters can be constructed using resistors and capacitors (RC filters) or resistors and inductors (RL filters). More complex active filters, which use amplifying components like operational amplifiers, offer greater control over the filter's response and can provide signal gain. The sharpness of the frequency transition, known as the roll-off, is determined by the filter's order, with higher-order filters providing a steeper attenuation of unwanted frequencies.