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实测工字型电感进行信号耦合的线性度

news 2026/3/26 18:46:42

简介：本文研究了150kHz导航信号测量中的非线性问题。通过工字型电感耦合信号源进行测试，发现ADC数值与输入信号幅值存在非线性关系。实验使用数字万用表直接测量交流信号，确认非线性并非由耦合电感引起。进一步测试显示，第一级跟随放大信号与输入信号之间也存在非线性，且LC谐振回路交流电压与输入信号的非线性极性发生变化。分析表明，测量端输入电容可能改变了LC谐振频率，导致信号幅度下降。实验数据与图表清晰展示了这一非线性现象。

关键词：电感耦合，线性关系

信号耦合中的线性关系

导航信号线性度测量：150kHz

01工字型电感

一、背景

刚才测试了150kHz 采集信号的特性。利用两个工字型电感，将信号源的150kHz的正弦信号耦合到测量电路。使用 DG1062产生 0V 到5V 峰峰值的交流信号，测量对应的 ADC幅值。发现，整体上，出现了 ADC数值与输入信号幅值之间存在着一定的非线性。这究竟是什么原因。下面使用数字万用表直接测量交流信号，确认是否是耦合电感所带来的信号幅度的非线性。

二、测试结果

下面通过编程，测量输入信号与第一级跟随放大之后信号幅度之间的关系。使用 DM3068 数字万用表交流档测量信号的有效值。通过测量结果来看，第一级跟随放大信号幅值与输入信号之间就出现了非线性关系。

#!/usr/local/bin/python# -*- coding: gbk -*-#============================================================# TEST1.PY -- by Dr. ZhuoQing 2025-12-18## Note:#============================================================fromheadmimport*fromtsmodule.tsvisaimport*vdim=linspace(0,5,100)vac=[]dm3068open()dg1062open(96)forvinvdim:dg1062volt(1,v)time.sleep(1.5)vv=dm3068vac()vac.append(vv)printff(v,vv)tspsave("measure",vdim=vdim,vac=vac)plt.plot(vdim,vac,lw=3)plt.xlabel("Input(V)",color="steelblue",fontsize=24)plt.ylabel("Measure(V)",color="steelblue",fontsize=24)plt.grid(True,which='both',linestyle='--',alpha=0.7)plt.tight_layout()plt.show()#------------------------------------------------------------# END OF FILE : TEST1.PY#============================================================

vdim=[0.0000,0.0505,0.1010,0.1515,0.2020,0.2525,0.3030,0.3535,0.4040,0.4545,0.5051,0.5556,0.6061,0.6566,0.7071,0.7576,0.8081,0.8586,0.9091,0.9596,1.0101,1.0606,1.1111,1.1616,1.2121,1.2626,1.3131,1.3636,1.4141,1.4646,1.5152,1.5657,1.6162,1.6667,1.7172,1.7677,1.8182,1.8687,1.9192,1.9697,2.0202,2.0707,2.1212,2.1717,2.2222,2.2727,2.3232,2.3737,2.4242,2.4747,2.5253,2.5758,2.6263,2.6768,2.7273,2.7778,2.8283,2.8788,2.9293,2.9798,3.0303,3.0808,3.1313,3.1818,3.2323,3.2828,3.3333,3.3838,3.4343,3.4848,3.5354,3.5859,3.6364,3.6869,3.7374,3.7879,3.8384,3.8889,3.9394,3.9899,4.0404,4.0909,4.1414,4.1919,4.2424,4.2929,4.3434,4.3939,4.4444,4.4949,4.5455,4.5960,4.6465,4.6970,4.7475,4.7980,4.8485,4.8990,4.9495,5.0000]vac=[0.0010,0.0101,0.0203,0.0306,0.0410,0.0514,0.0619,0.0724,0.0830,0.0936,0.1042,0.1148,0.1255,0.1362,0.1472,0.1580,0.1690,0.1800,0.1912,0.2024,0.2135,0.2240,0.2355,0.2472,0.2588,0.2703,0.2818,0.2935,0.3054,0.3172,0.3292,0.3412,0.3532,0.3653,0.3775,0.3895,0.4019,0.4139,0.4264,0.4389,0.4478,0.4604,0.4731,0.4858,0.4988,0.5118,0.5250,0.5381,0.5508,0.5638,0.5770,0.5902,0.6036,0.6174,0.6307,0.6440,0.6579,0.6713,0.6849,0.6989,0.7126,0.7265,0.7406,0.7552,0.7694,0.7839,0.7982,0.8125,0.8269,0.8421,0.8572,0.8722,0.8874,0.9026,0.9188,0.9345,0.9496,0.9648,0.9806,0.9974,1.0138,1.0300,1.0455,1.0613,1.0772,1.0938,1.1102,1.1262,1.1425,1.1588,1.1751,1.1920,1.2090,1.2261,1.2441,1.2622,1.2798,1.2971,1.3145,1.3327]

▲ 图1.2.1 输入信号与跟随放大信号幅度

是否因为放大器引起的问题？接下来，直接测试运放之前的信号幅度。奇怪的事情发生了，直接测量 LC 谐振回路的交流电压，与输入信号之间还有非线性关系，但是，非线性的极性变化了，也就是增长速度变化不同。对比一下，经过高速运放信号与没有经过高速运放的交流信号在增长规律上是不同的。在信号比较大的情况下，直接测量对应的信号幅度下降了很多，猜测是万用表测量端的输入电容改变了 LC 谐振频率引起的。

vdim=[0.0000,0.0505,0.1010,0.1515,0.2020,0.2525,0.3030,0.3535,0.4040,0.4545,0.5051,0.5556,0.6061,0.6566,0.7071,0.7576,0.8081,0.8586,0.9091,0.9596,1.0101,1.0606,1.1111,1.1616,1.2121,1.2626,1.3131,1.3636,1.4141,1.4646,1.5152,1.5657,1.6162,1.6667,1.7172,1.7677,1.8182,1.8687,1.9192,1.9697,2.0202,2.0707,2.1212,2.1717,2.2222,2.2727,2.3232,2.3737,2.4242,2.4747,2.5253,2.5758,2.6263,2.6768,2.7273,2.7778,2.8283,2.8788,2.9293,2.9798,3.0303,3.0808,3.1313,3.1818,3.2323,3.2828,3.3333,3.3838,3.4343,3.4848,3.5354,3.5859,3.6364,3.6869,3.7374,3.7879,3.8384,3.8889,3.9394,3.9899,4.0404,4.0909,4.1414,4.1919,4.2424,4.2929,4.3434,4.3939,4.4444,4.4949,4.5455,4.5960,4.6465,4.6970,4.7475,4.7980,4.8485,4.8990,4.9495,5.0000]vac=[0.0009,0.0120,0.0242,0.0364,0.0485,0.0607,0.0727,0.0847,0.0967,0.1085,0.1203,0.1320,0.1434,0.1550,0.1666,0.1780,0.1894,0.2008,0.2120,0.2225,0.2337,0.2447,0.2559,0.2669,0.2778,0.2887,0.2995,0.3103,0.3210,0.3317,0.3423,0.3529,0.3635,0.3738,0.3842,0.3946,0.4049,0.4152,0.4254,0.4355,0.4422,0.4524,0.4622,0.4722,0.4824,0.4924,0.5021,0.5121,0.5218,0.5316,0.5414,0.5510,0.5606,0.5704,0.5799,0.5893,0.5989,0.6068,0.6161,0.6257,0.6350,0.6445,0.6540,0.6635,0.6727,0.6819,0.6913,0.7005,0.7097,0.7190,0.7282,0.7371,0.7462,0.7550,0.7640,0.7730,0.7818,0.7909,0.7998,0.8085,0.8172,0.8264,0.8351,0.8439,0.8523,0.8606,0.8695,0.8784,0.8871,0.8955,0.9041,0.9125,0.9211,0.9301,0.9389,0.9476,0.9562,0.9649,0.9735,0.9819]

▲ 图1.2.2 输入信号与耦合后的信号

※总结 ※

本文测量了电感耦合信号通道的线性问题。对比LC接收信号以及跟随放大信号与输入信号之间的关系。通过测量发现两者之间存在着差异。随着输入信号幅度增加， LC 回路信号与跟随放大之后的信号增加规律，存在着小的差异性。原以为测量中的非线性，是因为耦合电感带来的。现在看来，这个问题比想象的要复杂一些。对于这种测量结果，现在还是无法进行解释。

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