preemphasizes

Preemphasizes is a signal processing technique used to artificially boost certain frequencies in a signal before transmission or recording. This process is often employed in audio and radio broadcasting to counteract the natural roll-off of high frequencies that occurs during transmission or recording. By increasing the amplitude of higher frequencies, preemphasis ensures that they are not lost in the noise floor or attenuated too much by the medium. After the signal has been transmitted or recorded, a complementary process called deemphasis is applied at the receiver or playback device. Deemphasis reverses the preemphasis by attenuating the same frequencies that were boosted, thereby restoring the original spectral balance of the signal. This combination of preemphasis and deemphasis helps to improve the signal-to-noise ratio, especially for high-frequency components, leading to a clearer and more faithful reproduction of the original signal. It is a common practice in analog audio systems, such as FM radio broadcasting, and has also been used in older magnetic tape recording formats. The specific frequency response curves for preemphasis and deemphasis are standardized for different applications to ensure compatibility between transmitters and receivers.