Research Of Active Complex Filter Used In Wireless Transceiver

With the rise of Internet of things(IoT)technology,there are a lot of wireless terminals and various applications around us,such as smart home,automatic meter reading,sprinkler system,lighting system,weather monitoring,unmanned aerial vehicle(UAV),wireless body domain network(WBAN),car keyless access system(RKE),etc.It is foreseeable that will have more wireless devices be connected to the cloud in the near future.In the design of the whole IoT systems,the wireless sensor network nodes design is the key to complete the information collection and transmission.The wireless sensor network is a self-organizing network system and is formed through specific wireless communication standards(such as bluetooth,Zigbee,etc).The wireless sensor network is consisted of a large numbers of low power,low-cost,small sensor wireless transceivers and deployed in the terminal or monitoring area.It has high demand for power consumption and integration.Therefore,the research of low power consumption and high integration of RF wireless transceiver has a great significance to the whole IoT systems.As an important component module of RF wireless transceiver chip,the performance of the filter seriously affects the overall performance of the system.In this paper introduces the current mainstream wireless transceiver architecture and compares their advantages and disadvantages,and introduces the Low-IF receivers in detail because its wide application rang.Complex filter as an important module in Low-IF receivers,it can realize the function of image reject and channel choice.Based on the requirement of low power consumption and low cost in the application system,a new RC complex filter structure is proposed.Through the derivation of the transfer function,the system is optimized to improve the current efficiency and reduce the number of operational amplifier release in the filter,thus reducing the current consumption.The operational amplifier uses a master-slave control structure to ensure the constant current of the tail current in the linear region,and has a low operating supply voltage while guaranteeing the common-mode rejection ratio.In order to reduce the error that the filter will produce due to variations in process,voltage,and temperature changes,a calibration circuit module is designed for the filter and the frequency characteristics of the filter are corrected by the calibration of the RC time constant.The filter designs in this paper simulated by using the spectre simulation tools in Cadence platform under GSMC0.13?m process,and the center frequency of the filter is 500 KHz and the 3dB bandwidth is 270 KHz.The image inhibition ratio at the center frequency was 42.92 dB.The gain at the center frequency is 10.72 dB.The ripple in the passband is 0.454 dB.The filter's operating voltage is 0.7V and the overall power consumption is 0.54 mW.Meet the filter design requirements of the wireless sensor network.At last,this paper summaries the research of active complex filter and forecast the future design.