Research Of Clock And Data Recovery Circuit Based On Ultra Wide Band Communication

Health care system based on human body network is one of the most important tendency in future medical treatment.This system need to meet the requirement of miniaturization,remote control,real-time.And ultra wide band(UWB) has the advantages of high speed,low power consuming,and less complicated architecture.So we could make full use of such UWB characteristics to build a new wearable wireless body area network(WBAN)system for UWB communication.What’s more, the system mentioned above should be implemented in chips.Firstly,structure of receivers,number of branches,angle of antenna and decision method are considered.In this case,the impulse response of human body is simulated by MATLAB.So the structure of the receiver could be decided properly to reduce bit error rate(BER).Secondly,Verilog-A has been used to build the behavior level of CDR based on PLL.The non ideal factor,such as random noise of power,current and time mismatch during charge and discharge are concerned.Finally,to reduce the phase noise in frequency domain and jitter in time domain,a low noise sub-harmonic injection locked multiloop ring oscillator and CDR based on full speed dual loop with reference clock are implemented from circuit design and layout to tape out verification.To verify the theory and design mentioned above, two chips have been fabricated.One is the Injection-locked Ring VCO and standard Ring VCO.The other is CDR chip.In the circuit design,the proposed IL RVCO exhibits a measured phase noise of-112.37 dBc/Hz@1 MHz offset from the center frequency of 1 GHz, while dissipating a current of 8 mA excluding the buffer from a 1.8V supply voltage.When the speed of input NRZ is250 Mbps,the root-mean-square value of recovered clock is 2 ps.Which has enhanced about6 ps by comparing with the open loop.The performance of jitter and eye diagram verify the proposed Injection locked CDR.