第5章电压测量

1、第第5 5章章 电压测量电压测量5.1 概述5.2 电压标准5.3 交流电压的测量5.4 直流电压的数字化测量及A/D转换原理5.5 电流、电压、阻抗变换技术及数字多用表5.6 数字电压表测量的不确定度及 自动校准、自动量程技术5.7 电压测量的干扰及抑制技术211( )NkVukNt tu(t)Vp0UmTU01( )TUu t dtT01( )TUu t dtT20.637ppUVV2VTR20( )Tu tdtR201( )TVu t dtT10.7072ppVVVppVKV峰值有效值21.41/2pppVKVFVKV有效值平均值(1/2)1.112/2 2pFpVKV（）TTDVpCR

2、Lu(t)CDRLu(t)VpabVPu(t)tcminmax(),sdLRr CTR CTI0u(t)D1D2D3D4CCu(t)D1D2I001( )( )22Todmdmu tu tIdtTrrrroI( )u t201( )TVu t dtT2( )ut0TAu(t)Vrms2212(.)kVkVV峰峰值值检检波波表表头头( (读读数数= =) )Vpu(t)V22pVV2ppVV任意pV任意2pppVVKK任意任意任意任意2,pppppppppVVK VKVkkKKKKK任意任意任意任意任意任意任意21.4121.41ppKKp（任意波）峰值V（任意波）有效值V221222ppppK

3、KKKV平平均均值值检检波波表表头头( (读读数数= =) )u(t)V0.91.112 2FVVVKV0.9VV任意V任意0.9FFVKVK任意任意任意任意V,FFFFVVKVKVKkK任意任意任意任意任意0.91.11FFFFKKkKK任意任意任意0.90.9FK（任意波）均值V（任意波）有效值V0.910.91.1110.90.9FFFFFKKKKK1 1.4100%29%1.4 FVKV方波VVVVFK方波1 0.9100%11%0.9411( )(sinsin3sin5.)35pu tVtttVP0T=1uStu(t)224111.352ppVVV1pPVKV方波2222411111

4、0.9735792ppVV100%3%VV 峰峰值值检检波波器器步步进进分分压压器器直直流流放放大大器器uA步步进进分分压压器器斩斩波波稳稳零零式式放放大大器器uA(a)峰峰值值检检波波器器( (探探头头内内) )(b)步步进进分分压压器器宽宽带带交交流流放放大大器器均均值值检检波波器器uA输输入入电电路路A A/ /D D转转换换器器数数字字显显示示器器逻逻辑辑控控制制电电路路时时钟钟发发生生器器模模拟拟部部分分数数字字部部分分Vx1420.1mV100%0.05%200mV1100%0.05%2000( %)xmVVV ( %)mxxVVVV %xV%mV%mV( %)xVVn 字V%mV

5、%(0.01%0.005%)mxVV 斜斜波波电电压压发发生生器器QQSETCLRSR&000时时钟钟计计数数器器主主门门VrVx+-+-门门控控信信号号输输入入比比较较器器接接地地比比较较器器a计计数数输输入入0VxVx、V Vr r门门控控信信号号计计数数输输入入NV Vr rt1bT0T0 xVkTkT NrVkRCrVkRC0 xVkTkT N0rxVVT NRC0rVTRCxVN主主门门计计数数器器逻逻辑辑控控制制电电路路数数字字输输出出时时钟钟S1S2CRVx-VrVr积积分分器器比比较较器器-+-+S S1 1 S S2 2Vot0t1复复零零t2t3VoVomT1T2N

6、1N2t积积分分波波形形计计数数器器输输入入a.b.清清零零T0f0T011T02111tomxxtTVV dtVRCRC 10TxxVV dt1TRC32210()tomromrtTVV dtVVRCRC21xrTVVT221xrNVVeNN121xxrNNVVVe1rVeN21111()tsmomxsmxtTTVVvdtVvRCRCRC Ix9009090.90.1(200mV)200A A(200mV)2mA A(200mV)20mA A(200mV)200mA A(200mV)2A A恒恒流流源源( (可可调调) )A A/ /D DR Rx xIr-+A Am mp p恒恒流流源源( (可可调调) )A A/ /D D-+A Am mp pIrVrR1Rx精精密密电电阻阻VoVr取取样样电电阻阻1xorRVVR 1oxrVRRV A AC C/ /