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改進(jìn)型恒溫晶振三次方補(bǔ)償電路的研究與設(shè)計(jì)
2020年電子技術(shù)應(yīng)用第9期
譚傳武,劉紅梅
湖南鐵道職業(yè)技術(shù)學(xué)院 電務(wù)技術(shù)學(xué)院,湖南 株洲412001
摘要: 通信系統(tǒng)中收發(fā)同步離不開(kāi)精確的時(shí)鐘頻率源,時(shí)鐘頻率源的精確與否直接影響系統(tǒng)的可靠性,而AT切晶體是頻率源的重要組成部分,其頻率與溫度呈現(xiàn)三次函數(shù)的變化關(guān)系,導(dǎo)致其不適應(yīng)較寬溫度范圍的應(yīng)用場(chǎng)景。為克服溫度對(duì)頻率的直接影響,設(shè)計(jì)了一種用于溫度補(bǔ)償?shù)娜魏瘮?shù)發(fā)生電路,包括基準(zhǔn)源、一次方電壓產(chǎn)生電路、三次方產(chǎn)生電路及相加電路,在工作時(shí)能與AT切晶體產(chǎn)生的負(fù)溫度系數(shù)相抵消。仿真結(jié)果表明,基準(zhǔn)源電路恒定輸出1.8 V,三次方電路輸出波峰1.65 V、波谷0.85 V,加和后經(jīng)調(diào)整的補(bǔ)償電路產(chǎn)生波形波峰2.04 V、波谷1.74 V,很好地抑制了來(lái)自溫度變化引起的頻率誤差,解決了振蕩器輸出頻率隨溫度變化的問(wèn)題。
中圖分類(lèi)號(hào): TN433
文獻(xiàn)標(biāo)識(shí)碼: A
DOI:10.16157/j.issn.0258-7998.200258
中文引用格式: 譚傳武,劉紅梅. 改進(jìn)型恒溫晶振三次方補(bǔ)償電路的研究與設(shè)計(jì)[J].電子技術(shù)應(yīng)用,2020,46(9):51-56.
英文引用格式: Tan Chuanwu,Liu Hongmei. Design of cubic compensation circuit for constant temperature crystal oscillator[J]. Application of Electronic Technique,2020,46(9):51-56.
Design of cubic compensation circuit for constant temperature crystal oscillator
Tan Chuanwu,Liu Hongmei
Department of Communication and Signal,Hunan Railway Professional Technology College,Zhuzhou 412001,China
Abstract: In the communication system, the receiving and transmitting synchronization can not be separated from the accurate clock frequency source. The accuracy of the clock frequency source directly affects the reliability of the system. AT cut crystal is an important part of the frequency source. Its frequency and temperature show a cubic function relationship, which makes it not suitable for a wide range of temperature application scenarios. In order to overcome the direct influence of temperature on frequency, this paper designs a kind of cubic function generating circuit for temperature compensation, including reference source, primary voltage generating circuit, cubic generating circuit and adding circuit, which can cancel the negative temperature coefficient produced by AT cut crystal in operation. The simulation results show that the reference circuit has a constant output of 1.856 V, the third-order circuit has a peak of 1.65 V and a trough of 0.85 V, and the added compensation circuit has a peak of 2.04 V and a trough of 1.74 V. The frequency error caused by the temperature change is well suppressed, and the problem that the output frequency of the oscillator changes with the temperature is solved.
Key words : temperature compensation;VCO;cubic function;band gap reference;frequency source

0 引言

    隨著5G及物聯(lián)網(wǎng)技術(shù)的飛速發(fā)展,智能終端體積越來(lái)越小且數(shù)量越來(lái)越多[1-2],終端與基站之間通過(guò)無(wú)線(xiàn)電波完成信息交互,而精準(zhǔn)的時(shí)鐘頻率源是通信的必備條件[3-4]。石英晶體振蕩器的頻率準(zhǔn)確度會(huì)受溫度等因素的影響,市場(chǎng)上主流的振蕩器選用的是AT切型[5],其隨溫度變化頻率漂移可達(dá)10 ppm到50 ppm,AT切在室溫存在零偏移點(diǎn)[6]。南開(kāi)大學(xué)吳佳等采用7組差分對(duì)設(shè)計(jì)了高精度的三次方函數(shù)發(fā)生器[7],在±0.5×10-6且補(bǔ)償溫度范圍擴(kuò)大至-40~+85 ℃,此方法提高了精度但是功耗增加,不利于小型化的物聯(lián)網(wǎng)場(chǎng)景;西安電子科技大學(xué)的劉宇計(jì)了一種超高頻率穩(wěn)定度的模擬溫度補(bǔ)償晶體(ATCXO)振蕩器電路[8],可提供高精度的頻率源,但是溫度范圍受限,不適應(yīng)溫度極端的物聯(lián)網(wǎng)場(chǎng)景;華中科技大學(xué)肖鵬采用MOS可變電容設(shè)計(jì)了一款溫度補(bǔ)償晶體振蕩器(TCXO)芯片[9],壓控范圍可達(dá)±180 ppm,但頻率調(diào)整范圍受限。

    本文綜合以上設(shè)計(jì)的優(yōu)缺點(diǎn),改進(jìn)了可變電容設(shè)計(jì)的補(bǔ)償電路,利用CMOS工藝設(shè)計(jì)了一種用于TCXO振蕩器中的功耗低、溫度范圍-40~+120 ℃的補(bǔ)償電路,能抵消AT切晶體中隨溫度引起的頻率變化,可用在恒溫晶振中進(jìn)行頻率補(bǔ)償。




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作者信息:

譚傳武,劉紅梅

(湖南鐵道職業(yè)技術(shù)學(xué)院 電務(wù)技術(shù)學(xué)院,湖南 株洲412001)

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