The Research Of Spur And Power Noise In Wireless Receiver

Recent rapid development in wireless communication systems presents high utilizations of wireless spectrum.However,this brings a problem of spurious interferences that is becoming more and more serious.The power distribution network provides a good propagation path for the noise while providing power to the wireless receiver.Therefore,the power distribution network needs to supply enough power to the receiver while ensuring a good suppression of the power supply noise.In this paper,the research on the spurious and power supply noise in wireless receivers is carried out.The main research work and innovations of this thesis are summarized as follows:The second chapter studies the spur and phase noise related problems in a phase-locked loop?PLL?circuit.This chapter analyzes the relationship between the phase noise of a crystal oscillator output signal and the phase noise of the PLL output signal after the power supply noise of the crystal oscillator is deteriorated,and gives the phase noise measured results of the crystal oscillator and the PLL before and after the power supply noise of the crystal oscillator is suppressed.This chapter presents the first innovation of the paper:most of the measure equipment factories?such as Keysight Company?recommend using a phase noise analyzer to measure the jitter performance of a clock signal.The clock jitter performance of the rising edge and the falling edge of the clock signal may be significantly different,but the clock jitter measurement results of the phase noise analyzer cannot distinguish the difference between the rising edge jitter and the falling edge jitter of the clock signal.When precise clock jitter measurement is carried out,oscilloscopes should be used to collect and measure the rising and falling edges of the clock signal respectively,so as to distinguish the jitter performance difference between the rising and falling edges of the clock.The third chapter analyzes the problems of power supply noise in wireless receivers.This chapter introduces the source of power supply noise in wireless receivers,and focuses on the impact of power supply noise on the demodulation circuit of a wireless receiver.The measured results show that the performance of the receiver's demodulation circuit can be improved by reducing the parasitic inductance of the power supply.Finally,the influence of power supply noise on a VCO performance and the power supply noise suppression capability of LDO circuits are analyzed.The fourth chapter presents the design process of an elliptical band-stop filter and the related measured results of the designed elliptical band-stop filters.Some high order harmonics of a crystal oscillator can be coupled along the power distribution network to the supplier pin of a LNA in a Global Navigation Satellite System?GNSS?receiver.Since an elliptic function response filter has the advantages of rejection and selectivity for fewer components,a third order elliptic bandstop filter is proposed to suppress the high harmonics.A 1.58 GHz elliptic bandstop filter prototype is implemented with microstrip and lumped components to verify the performance.The measured results show that both bandstop filters obtain a stopband attenuation of 56 dB over the whole range of GNSS band,and can effectively rejection the high order harmonics of the crystal oscillator.The fifth chapter presents the design and experimental results of using EBG circuit to suppress the high-order harmonic spurs of crystal oscillator.This chapter proves the second innovation of the paper:This paper prove that the suppression bandwidth of CSRR?Complementary Split Ring Resonators?cells is not changed by inserting ceramic capacitors into CSRR cells but the suppression capability of CSRR cells can be improved in some special frequency bands.By adjusting different ceramic capacitors,we can easily adjust these frequency bands which need to enhance the suppression ability of EBG,and obviously enhance the flexibility of EBG circuit application.The sixth chapter introduces the design principle and design process of a low insertion loss elliptical bandpass filter.This chapter introduces the third innovation of the paper:The elliptic function response filters have the advantages of insertion loss and selectivity,but it is usually difficult to be directly realized with microstrip,since the elliptic bandpass filter owns branches consisting of a serial resonator and a parallel resonator.The parallel branch of narrow-band elliptic function bandpass filter consisting of series resonator and parallel resonator is analyzed in this paper.Through complete mathematical analysis,we find that the parallel branch composed of series resonator and parallel resonator in elliptic bandpass filter can be completely replaced by two parallel series resonators,and the equivalent two parallel series resonant branches can be easily realized by microstrip lines.In order to improve the stopband rejection ability of band-pass filter,we insert two additional transmission zeros into the filter to enhance the out-of-band rejection ability of band-pass filter.Using direct transformation of the transmission zeros,a band-pass elliptic filter with a center frequency of 2.45 GHz is designed.The insertion loss of the band-pass filter is less than 0.8 dB,and the ratio of?f₍3?9?/?f₍20?9?is higher than 0.55,which shows that the band-pass filter has a very high adjacent channel rejection performance.