發(fā)布時間：2018-11-26 07:10

【摘要】：北斗衛(wèi)星導航定位系統(tǒng)是我國獨立自主研發(fā)的全球衛(wèi)星定位和通信導航系統(tǒng)，在如交通導航、授時、地質勘探、地理測繪等軍用作業(yè)及民用生活中存在廣闊的應用空間。衛(wèi)星導航定位數(shù)據(jù)經過的無線信道傳輸距離遠、電磁干擾復雜，又由于采用擴頻技術，使得北斗射頻信號的輻射功率譜極低，淹沒于噪聲基底以下，因此對北斗地面射頻接收前端的接收靈敏度及自動增益調節(jié)動態(tài)范圍性能等方面提出了較苛刻的要求。為了使北斗衛(wèi)星地面導航定位系統(tǒng)可以適應各種惡劣復雜的地面作業(yè)環(huán)境，，用于射頻接收前端電路的自動增益控制(AGC)芯片顯得尤為重要，是地面接收系統(tǒng)靈敏度、動態(tài)范圍、可靠性及誤比特率性能的關鍵保證。 針對北斗衛(wèi)星導航定位接收系統(tǒng)的應用，本文研究設計了一款具有大動態(tài)范圍、高線性度的自動增益控制芯片，芯片包括可變增益放大器(VGA)、電荷泵(CP)及模數(shù)轉換器(ADC)等模塊，可以實現(xiàn)對下變頻后中頻信號的增益自動控制放大。針對衛(wèi)星信號功率微弱、動態(tài)范圍大的特點，本文提出了一種新型的具有跨導提高(gm-boosting)技術的可變增益放大電路結構，使電路的指數(shù)增益(dB-linear)范圍和三階交調性能得到顯著改善；提出了一種改進型的電荷泵，通過額外的充放電電流能使電荷泵的輸出電壓快速穩(wěn)定至可變增益放大器所能調節(jié)的范圍，有效縮短了AGC芯片的穩(wěn)定時間。 本文采用Global Foundry180nm CMOS工藝對提出的大動態(tài)自動增益控制芯片進行了前端電路設計、后端物理版圖的設計與驗證。芯片采用1.8V供電，后仿真結果顯示：芯片中的VGA增益范圍為-27dB~75dB，dB-linear范圍達到75dB(誤差±1dB)；AGC芯片的最大線性放大帶寬為25MHz，輸入三階交調點達到-38dBm，穩(wěn)定時間小于130s，消耗電流1.9mA，可以滿足高端北斗衛(wèi)星地面導航系統(tǒng)對接收靈敏度及動態(tài)范圍冗余度的苛刻要求。
[Abstract]:Beidou satellite navigation and positioning system is a global satellite positioning and communication navigation system developed independently in China. It has a wide application space in military operations and civil life such as traffic navigation, timing, geological exploration, geographical mapping and so on. Satellite navigation and positioning data pass through a long distance of wireless channels, electromagnetic interference is complex, and because of the spread spectrum technology, the radiation power spectrum of Beidou radio frequency signal is extremely low, which is submerged under the noise base. Therefore, the requirements of the receiver sensitivity and the dynamic range performance of automatic gain regulation for the Beidou ground RF receiver front end are put forward. In order to make the Beidou satellite ground navigation and positioning system adapt to all kinds of harsh and complex ground operation environment, the automatic gain control (AGC) chip used in RF front-end circuit is especially important, which is the sensitivity of the ground receiving system. Key guarantees for dynamic range, reliability and bit error rate performance. Aiming at the application of Beidou satellite navigation and position receiving system, this paper designs an automatic gain control chip with large dynamic range and high linearity. The chip includes variable gain amplifier (VGA),). Charge pump (CP) and analog-to-digital converter (ADC) modules can automatically control and amplify the gain of downconversion if signal. Aiming at the characteristics of weak power and large dynamic range of satellite signal, a new type of variable gain amplifier with transconductance enhancement (gm-boosting) technology is proposed in this paper. The exponential gain (dB-linear) range and the third-order intermodulation performance of the circuit are improved significantly. An improved charge pump is proposed. The output voltage of the charge pump can be rapidly stabilized to the range that the variable gain amplifier can adjust by the extra charge and discharge current, and the stable time of the AGC chip can be effectively shortened. In this paper, Global Foundry180nm CMOS technology is used to design the front circuit of the proposed large dynamic automatic gain control chip, and the physical layout of the back end is designed and verified. The chip uses 1.8 V power supply, and the post-simulation results show that the gain range of VGA in the chip is -27dBU 75dBB-linear 75dB (error 鹵1dB); The maximum linear amplification bandwidth of the AGC chip is 25MHz, the input third-order intermodulation point reaches -38dBm, the stabilization time is less than 130s, and the current consumption is 1.9 Ma. It can meet the strict requirements of receiving sensitivity and dynamic range redundancy of high-end Beidou satellite ground navigation system.
【學位授予單位】：華南理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN965.5

【參考文獻】

相關博士學位論文 前1條

1 李兵;多模兼容衛(wèi)星導航接收機射頻前端芯片關鍵技術研究[D];西安電子科技大學;2011年

本文編號：2357740