【摘要】：晶體振蕩器作為現(xiàn)代電子系統(tǒng)和電子設(shè)備的頻率源,廣泛應(yīng)用于通信、導(dǎo)航、雷達、車載電子以及精密時頻計量儀器等領(lǐng)域。溫度頻率穩(wěn)定度是晶體振蕩器的重要性能指標(biāo)之一,普通的晶體振蕩器因為石英晶體的諧振頻率隨溫度發(fā)生偏移,導(dǎo)致其溫度頻率穩(wěn)定度不高,無法滿足高端產(chǎn)品對頻率穩(wěn)定度的嚴苛要求。目前有熱敏電阻補償技術(shù)、模擬溫度補償技術(shù)、數(shù)字溫度補償技術(shù)和微處理器溫度補償技術(shù)改善晶體振蕩器的溫度頻率特性。本論文設(shè)計了一款高精度晶體振蕩器芯片,產(chǎn)生10M、40M和50M三個頻點的弦波信號。首先采用Colpitz結(jié)構(gòu)設(shè)計了振蕩電路,對振蕩電路的起振、線性小信號模型和相位噪聲進行了理論分析,并基于理論分析優(yōu)化了相位噪聲性能;隨后基于AT切晶體設(shè)計了一種結(jié)構(gòu)新穎的模擬溫度補償電路產(chǎn)生對溫度呈三次方的補償電壓改善晶體振蕩器的頻率溫度穩(wěn)定度,該電路包括可調(diào)的PTAT電流源、可調(diào)的CTAT電流源、可調(diào)的非線性電流源、電流求和模塊以及可調(diào)的電流-電壓轉(zhuǎn)換器。通過改變可調(diào)電阻的值和譯碼器的控制字分別實現(xiàn)低溫段零溫系數(shù)點和高溫段零溫系數(shù)點可調(diào);最后提出了采用人工神經(jīng)網(wǎng)絡(luò)對晶體振蕩器的溫度頻率特性進行校正的方案,構(gòu)建了基于人工神經(jīng)網(wǎng)絡(luò)的溫度補償晶體振蕩器系統(tǒng),由包括人工神經(jīng)網(wǎng)絡(luò)的溫度補償電壓產(chǎn)生模塊、時序控制模塊和振蕩模塊組成,并闡述了該系統(tǒng)的三個工作過程:訓(xùn)練數(shù)據(jù)采集、神經(jīng)網(wǎng)絡(luò)訓(xùn)練和工作階段。本設(shè)計晶體振蕩電路和模擬溫度補償電路分別在TSMC25um BCD工藝和GSMC13um RF工藝下流片,版圖面積分別為1130×700um2和120×180um2。晶體振蕩器測試結(jié)果如下:外形尺寸1.2 mm×1 mm×0.8 mm,能夠工作在3.3V和5V電源電壓下,工作溫度范圍-40?C~+85?C,10M、40M和50M三個頻點的功耗分別是8mA、9mA和11mA,輸出幅度分別是5.6dBm、5.1dBm和5.1dBm,二次諧波抑制分別是-37dBm、-36dBm和-36d Bm,相位噪聲性能是:10M:≤-124dBc/Hz@100Hz;≤-150dBc/Hz@1kHz;≤-158dBc/Hz@10kHz.40M:≤-111dBc/Hz@100Hz;≤-139dBc/Hz@1kHz;≤-149dBc/Hz@10kHz.50M:≤-102dBc/Hz@100Hz;≤-137dBc/Hz@1kHz;≤-150dBc/Hz@10kHz-40?C~+100?C的溫度范圍內(nèi),溫度頻率穩(wěn)定度的仿真結(jié)果是±5ppm。
[Abstract]:Crystal oscillator, as the frequency source of modern electronic system and electronic equipment, is widely used in the fields of communication, navigation, radar, onboard electronics and precision time-frequency measurement instruments. The temperature frequency stability is one of the important performance indexes of crystal oscillator. Because the resonance frequency of quartz crystal deviates with temperature, the temperature frequency stability is not high. Unable to meet the stringent requirements of high-end products for frequency stability. At present, there are thermistor compensation technology, analog temperature compensation technology, digital temperature compensation technology and microprocessor temperature compensation technology to improve the temperature and frequency characteristics of crystal oscillator. In this paper, a high precision crystal oscillator chip is designed to generate three frequency chord wave signals of 10 MN 40 M and 50 M. Firstly, the oscillation circuit is designed with Colpitz structure. The oscillation circuit, linear small signal model and phase noise are analyzed theoretically, and the phase noise performance is optimized based on the theoretical analysis. Then a novel analog temperature compensation circuit based on AT crystal is designed to improve the frequency and temperature stability of the crystal oscillator. The circuit includes adjustable PTAT current source and adjustable CTAT current source. Adjustable nonlinear current source, current summation module and adjustable current-voltage converter. By changing the value of the resistor and the control word of the decoder, the zero temperature coefficient point of the low temperature section and the zero temperature coefficient point of the high temperature section can be adjusted respectively. Finally, an artificial neural network is proposed to correct the temperature and frequency characteristics of the crystal oscillator, and a temperature compensated crystal oscillator system based on the artificial neural network is constructed. It is composed of temperature compensation voltage generation module, timing control module and oscillation module including artificial neural network. The three working processes of the system are described: training data collection, neural network training and working stage. The crystal oscillation circuit and the analog temperature compensation circuit are designed in TSMC25um BCD process and GSMC13um RF process respectively. The layout area is 1130 脳 700um2 and 120 脳 180 um2, respectively. The test results of the crystal oscillator are as follows: the shape size of 1.2 mm 脳 1 mm 脳 0.8 mm, can work at 3.3V and 5V power supply voltages, and the power consumption at the operating temperature range of -40C ~ 85C _ (10) M ~ (10) M ~ (40) M and 50 M is 8 Ma ~ (9) Ma and 11 Ma, respectively. The output amplitudes are 5.1dBm and 5.1dBm, and the second harmonic suppression is -37dBmg-36dBm and -36d Bm, phase noise respectively: 10m: 鈮，

本文編號：2307816