Generally, the equalizer on the mixer can only adjust the high frequency, intermediate frequency and low frequency electrical signals respectively. In communication system, inserting equalizer in baseband system can reduce the influence of intersymbol interference.
Extended data
Types of equalizers
Frequency domain equalizer
Frequency domain equalizer uses the frequency characteristics of tunable filter to compensate the amplitude-frequency characteristics and group delay characteristics of the actual channel, so that the total frequency characteristics of the whole system including equalizer can meet the transmission conditions without intersymbol interference.
Time domain equalizer
The time domain equalizer directly considers the time response, so that the impulse response of the whole transmission system including the equalizer meets the condition of no inter-symbol interference. Frequency domain equalization meets the requirements of Nyquist shaping theorem, and the condition of no intersymbol interference is relatively loose only at the decision point. Therefore, time domain equalizer is widely used in digital communication.
Time domain equalizers can be divided into two categories: linear equalizers and nonlinear equalizers. If the decision result in the receiver is fed back for parameter adjustment of the equalizer, it is a nonlinear equalizer;
On the contrary, it is a linear equalizer. In linear equalizer, the most commonly used equalizer structure is linear transverse equalizer, which consists of several tapped delay lines, and the delay time interval is equal to the symbol interval. There are many kinds of nonlinear equalizers, including decision feedback equalizer (DFE), maximum likelihood (ML) symbol detector and maximum likelihood sequence estimation.
Reference source? Baidu encyclopedia-equalizer
Baidu encyclopedia-sound equalizer