Reseach On Mixed Signal Equalizer Design

In nearly a decade, the world goes into the mobile internet era gradually, people are becoming more and more rely on smart handheld devices to meet their demands for multimedia, social communication and commercial activities. The development of wireless mobile communication also unceasingly enhances transfer rate and communication stability to meet the demands of people. Short distance wireless communication changes the terminal access method further, the terminal within the local area network(LAN) can get higher transmission rate. Because the wide passband feature of the 60 GHZ high rate wireless communication, this becomes the advantage of using it in short distance wireless communication.60 GHz communication can provide more than 1 gb/s transmission rate.The standardization of 60 GHz wireless communication matures gradually, the IEEE 802.11 ad working group standardizes the 60 GHz wireless communication system, it provides a channel model analysis method, the IEEE 802.11 ad standard supports single carrier transmission and OFDM transmission at the same time. This article introduces the 60 GHz technology background and current development of the wireless communication system firstly. Then we emphatically analyze the 60 GHz short distance scenes and multipath fading characteristics of wireless communication, and simulate the channel of the meeting room and living room as two of the most common application scenarios, including the STA- STA communication mode and the STA- AP mode. From the simulation results,we can get 802.11 ad channel multipath fading character, intersymbol interference effects tens of to hundreds of receive codes.Equalizer is used to eliminate the intersymbol interference signals, channel impulse response delays too long will lead to the complexity of the equalizer. This paper aims to discover the design method of channel equalizer, OFDM technology and single carrier frequency domain equalization technology requires the processing of FFT and IFFT, also bring a lot of hardware overhead. And then we focuses on the design of the single carrier time-domain equalizer, including ZF criterion and MMSE criterion.and simulate the IEEE 802.11 ad communication system performance of single carrier time domain equalization.Mixed-signal equalizer structure is used to eliminate the intersymbol interference of IEEE 802.11 ad communication channel, solves the problem that pure digital time-domain equalizer circuit’s taps are too many. This article analysis the mixed-signal equalizer using analog circuit network and single carrier time-domain equalizer. Analog circuit network mathematical model is transfer function model. The zero point and pole of the analog circuit network passive circuit implements with input impedance, the circuit implementation use ladder network, analog circuit network optimizates using numerical direct optimization design method. Finally we will discuss mixed-signal equalizer design.