高频电子线路习题答案（第五版）张肃文

看不惯那些家伙。 高频电子第五版

3?1解：f0?1MHz2Δf0.7?1?106?990?103?10(kHz)f01?106Q???1002Δf0.710?103取R?10Ω则L?C?QR?01?100?10?159(?H)2?3.14?1061?159(pF)?02L(2?3.14?106)2?159?10?6

113?2解：(1)当?01?或ω?时，产生并联谐振。02L1C1L2C2?(2)当?01?(3)当?01?1或ω02?L1C11或ω02?L1C11时，产生串联谐振。L2C21时，产生并联谐振。L2C2

1L1)R2??jω0LR(1?2)R2?Ljω0CCω0LCC?R3?3证明：Z???112RR?jω0L?R?2R?jω0L(1?2)jω0Cω0LC 223?4解：1?由?15?C??1605??450?C?535得C?40pF(R?jω0L)(R?由?12?C??16052??100?C?5352得C?-1pF?不合理舍去?故采用后一个。2?L?3?

L C C’

11??180?μH??02?C?C???2?3.14?535?103?2??450?40??10?12

3?5解：Q0?11??2126-12?0C0R2?3.14?1.5?10?100?10?5L0?11??112?μH?226-12?0C0?2?3.14?1.5?10?100?10Vom1?10-3Iom???0.2?mA?R5VLom?VCom?Q0VSm?212?1?10-3?212?mV?113?6解：L?2??253?μH??0C2?3.14?1062?100?10?12

??Q0?VC10??100VS0.1C?CX11?2??100?pF??CX?200pFC?CX?0L?2?3.14?106?2?253?10?62?3.14?106?253?10?62?3.14?106?253?10?6RX?????47.7?Ω?QQ02.50.1100?0L?0L11?47.7?j?47.7?j796?Ω?6?12?0CX2?3.14?10?200?10113?7解：L?2??20.2?μH?ω0C?2?3.14?5?106??50?10?12ZX?RX?jf05?106100Q0???2Δf0.7150?10332Δf1002??5.5?5??10620ξ?Q0???6f035?103??2?2?f0.7，则Q??因2Δf0.7，所以应并上21kΩ电阻。 0?0.5Q0，故R?0.5R2πf0CωC3?8证明：4πΔf0.7C??0?g?f02Δf0.7Q

?C?C0?C1?5??20?20?20?18.3?pF?3?9解：C?Ci?2C2?C0?C120?20?20f0?11??41.6?MHz??6?122πLC2?3.140.8?10?18.3?10L?100?C120.8?10?6?20.9?kΩ??20?20??10?1222RP?Q0?C2?C0?C1??20?20?20??R??RiRP?R?1020.9???5?5.88?kΩ???0C20??1??R?5.88?103QL???28.26?6ω0L2?3.14?41.6?10?0.8?102Δf0.7f041.6?106???1.48?MHz?QL28.2

3?12解：1?Zf1?02?Zf1?03?Zf1?R

3?13解：1?L1?L2?C1?C2?ρ1103??159?μH?62?3.14?10?0111??159?pF?226?6?01L1?2?3.14?10??159?10ηR1?20M?1??3.18?μH?6?012?3.14?102?Zf1??01M?2?R2?2?3.14?10?6?3.18?10?6??20?Ω?202L1159?10?6ZP???25?kΩ??12?R1?Rf1?C1?20?20??159?103?Q1??01L1R1?Rf12?3.14?106?159?10?6??2520?204?2Δf0.7??5?C2f0f0106?20?2?2?2??28.2?kHz?Qρ1R110312????02L2?1?2?3.14?950?10?32?159?10?6?177?pF??1?Z22?R2?j??L??021?C???022??1???20?j?2?3.14?106?159?10?6??20?j1006?12?2?3.14?10?177?10??Zf1??01M?2?Z22?2?3.14?10??6?3.18?10?6??0.768?j3.84?Ω?20?j10062

3?15解：?R?L159?10??20????R1RPC50?103?159?10?12?Rf1?0?M?0f0106Q?2?2?1002?f0.714?103

3?16解：1?Rf1??01M?2?R2?10?7?10?6??20???52Rab?2???3?Q??RR1??01L?21?Rf1??10?7?100?10?6??40?k??5?202?01M?01LR1107?10?6??25107?100?10?6??20052?f0.711??2?2??1??22?2?2?1??0.013f0Q200 I1113?17解：????Q??22.522I01.25?2?f??10?103?1??1???Q?300?103???Q?f????0??11R???11.8Q?0C22.5?2?3.14?300?103?2000?10?12?2?f??10?103?1??1???Q300?103???Qf????0??Q?Q??30?22.5?7.51?2ω?串联联谐??L1?375μHL2C?3?18解：???1?L2?125μ?ω?并联联谐?L1?L2?C??

I?I012?12?1?Q?302

4?5解：当f?1MHz时，??β0?β0f1???f?Tβ0?β0f1???f?Tβ0?β0f1???f?T????????????2?50?50?106?1???250?106????502?49当f?20MHz时，??2?当f?50MHz时，??2??50?20?101???250?106?506????2?12.1?50?50?106?1???250?106????2?5

4?7解：gb?e?gm?Cb?eIE1??0.754?mS?26?β0?1?26??50?1?β0?50?0.754?10?3?37.7?mS?rb?egm37.7?10?3???24?pF?62πfT2?3.14?250?10a?1?rbb?gb?e?1?70?0.754?10?3?1b?ωCb?erbb??2?3.14?107?24?10?12?70?0.1yie?gb?e?j?Cb?e??a?jb??0.754?10?3???a2?b2?0.895?j1.41?mS?j2?3.14?107?24?10?12???1?j0.1?12?0.12j2?3.14?107?3?10?12??1?j0.1?yre??0.0187?j0.187?mS?2222a?b1?0.1gm?a?jb?37.7?10?3??1?j0.1?yfe???37.327?j3.733?mS?a2?b212?0.12?g?j?Cb?c??a?jb??j?C?1?rga?jb?yoe?gce?j?Cb?c?rbb?gmb?c?b?c?bb?ma2?b2a2?b2??1?j0.1???j2?3.14?107?3?10?12?1?70?37.7?10?3?2?0.049?j0.68?mS?2?1?0.1???Av?4?8解：令??A???vo??Av?令??A???vo?mm?g?j?Cb?c??a?jb?????b?c??????4??Q2Δf?4??Q2Δf420.7f0?4????1?2?m得2Δf0.71?m?f0???44?2?1??Q???????20.1f0?4????1?10?10?12?11m2mm得2Δf0.12?m?f0???44?10?1??Q??故Kr0.1?2Δf0.1?2Δf0.742?m??4?10?1????1?m??4?2?1?????4

4?9解：p1?gp?N235??0.25N1320p2?N455??0.25N132011??37.2?μS?6?6ω0Q0L2π?10.7?10?100?4?1011?6?6?200?10??2860?10?228.5?μS?22442g??gp?p12goe?p2gie?37.2?10?6?Avo?p1p2yfegΣ0.25?0.25?45?10?3??12.3?6228.5?102Apo?Avo?12.32?151.3QL?2Δf0.711??16.3?66?6gΣω0L228.5?10?2π?10.7?10?4?10f010.7?106???0.657?MHZ?QL16.3?2?2?QL??16.3??K??1???1???1.43?Q??100?0???fe??re?54o?88.5oξ?tan?tan??2.95222gp?p2gie37.2?10?6?0.252?200?10?6g??3008.8?μS?L?22p10.25yfeyre?gs?gie??goe?g?1?ξ2?2?2860?10?6?200?10?6?3008.8?10?6??1?2.952?L??S????145?10?30.31?10?3

?1?gp?4?10解：11??0.037?mS?6?6Q0ω0L100?2?3.14?10.7?10?4?1012?p12goe?p2gie??0.037?0.1?0.32?0.082?0.32?0.15??0.158?mS?R50.3?0.3?382?4.22??21.780.158g??gp?Avo?p1p2yfeg??2?2Δf0.7?ω0Lg?f0?2?3.14??10.7?106?2?4?10?6?0.158?10?3?454.4?kHz??3??Avo?4??Avo?4?21.784?225025.38?4??2Δf0.7?4??5?2Δf0?.7?142?1?2Δf0.7?2?1?454.4?197.65?kHz??1044.6?kHz?14142Δf0.72?12Δf0?.7?2Δf0.7?1044.6?454.4?590.2?kHz???AvoAvo2Δf0.721.78?454.4??9.47?2Δf0.71044.6??4??Avo??4?9.474?8042.66?Avo??4?225025?Avo?4??Avo.38-8042.66?216982.724?11解：C??C?p12Coe?500?0.32?18?501.62?pF?L?1

?2πf0?C?2?1?2?3.14?1.5?10??62?501.62?10?12?22.5?μH?

Kr0.1?1.9不能满足?Avo?S?4?14解：yfe2.5?0Cre26.42?36.42?7.742.5?0.3

4?17解：L1?11??118?μH?223?12ω0C1?2π?465?10??1000?10118118118L36?L2?L34?L56???60??13.5?120737373C12?C1?Co?1000?4?1004?pF??13.5?C36?C2?pCi?1000????40?1004?pF??74.5?ω0C12π?465?103?1000?10?12?6g12?go??20?10??49?μS?Q0100222ω0C2?13.5?2π?465?103?1000?10?12?3g36?pgi????49?μS???0.62?10?Q0100?74.5??初、次级回路参数相等。若为临界耦合，即??1，则13.5?31??40?10p1p2yfe74.5Avo???74g2?49?10?6222ω0C122π?465?103?1004?10?12QL???60?6g1249?102Δf0.7f0465?103?2?2??10.9?kHZ?QL60

Kr0.1?3.1624?20解:vn?4kTRΔfn?4?1.38?10?23?290?1000?107?12.65?μV?2in?4kTGΔfn?4?1.38?10?23?290?10-3?107?12.65?nA?22224?21解：?vn?vn1?vn2?vn3?4kT1R1Δfn?4kT2R2Δfn?4kT3R3Δfn

?4k?T1R1?T2R2?T3R3?Δfn?4kT?R1?R2?R3?Δfn?T?T1R1?T2R2?T3R3R1?R2?R32222又?in?in1?in2?in3?4kT1G1Δfn?4kT2G2Δfn?4kT3G3Δfn?4k?T1G1?T2G2?T3G3?Δfn?4kT?G1?G2?G3?Δfn?T?T1G1?T2G2?T3G3R1R2T3?R2R3T1?R3R1T2?G1?G2?G3R1R2?R2R3?R3R1

4?18证明：1?Ib1?yieVbe1?yreVce1???1?Ic1?yfeVbe1?yoeVce1???2?Ib2?yieVbe2?yreVce2Ic2?yfeVbe2?yoeVce2????????????????yieVce1?yre?Vcb2?Vce1??yreVcb2??yie?yre?Vce1???3???????????yfeVce1?yoe?Vcb2?Vce1??yoeVcb2??yfe?yoe?Vce1???4??????????????2???3?得Ic2?yfeVbe1??yie?yre?yoe?Vce1?yreVcb2Vce1??Ic2?yreVcb2?yfeVbe1yie?yre?yoe????????5?Ic2?yreVcb2?yfeVbe1yie?yre?yoe????5?代入?4?Ic2?yoeVcb2??yfe?yoe?Ic2?2??yfe?yfe?yoe?yieyoe?yreyfe?yoe?Vbe1?Vcb2???6?yie?yre?yfe?2yoeyie?yre?yfe?2yoe?yf?yfe?yfe?yoe??yfeyie?yre?yfe?2yoe由?1?乘?yfe?yoe?与?4?乘yre后相加得Ib1?yfe?yoe??Ic2yre?yie?yfe?yoe?Vbe1?yreyoeVcb2由?6?代入消去Ic2得Ib1?2?yie?yieyre?yieyfe?2yieyoe?yreyfe?yre?yoe?yre??Vbe1?Vcb2yie?yre?yfe?2yoeyie?yre?yfe?2yoe?????2yieyoe?yreyfe?yoeyo???yreyie?yre?yfe?2yoe2yie?yieyre?yieyfe?2yieyoe?yreyfeyi??yieyie?yre?yfe?2yoeyr?yre?yoe?yre?y?y?yre???reoeyie?yre?yfe?2yoeyfe略同理可证2?24?22解：vbn?4kTrb?fn?4?1.38?10?23??273?19??70?200?103?0.226?10?12?V2?2ien?2qIE?fn?2?1.6?10?19?10?3?200?103?0.64?10?16?A2????0?f?1???f?????2?0.95?10?10?1???500?106????62?0.952icn?2qIC?1??0??fn?2?1.6?10?19?10?3??1?0.95??200?103?0.32?10?17?A2?

4?23证明：?fn???0A2?f?dfA2?f0????1204?24解：Fn高?3dB?1.995倍?Fn混?1?Fn?Fn高?f?f0??1??2Q??f0??Fn中?6dB?3.981倍?df??f02Q

Ti60?1??1.207T290F?1Fn中?11.207?13.981?1?n混??1.995???10Ap高KpcAp高Ap高0.2?Ap高20lg1.888?2.76?dB?2sAp高?1.888

4?25解：Fn?PsiPniPPV4RsR?RR11?no???s?2?s?1?sPsoPnoPniApApPoPsPoVs4?Rs?R?RR PsiPniPsIs24GsG?GL?rCL14?26解：Fn????2?1?PsoPnoApPoIs4?Gs?G?GL?rCL?GsAPA?6dB?3.981倍?Fn?FnA?ApB?12dB?15.849倍?

4?27解：A为输入级，B为中间级，C为输出级。F?1FnB?12?14?1?nC?1.7???2ApAApA?ApB3.9813.981?15.8494?28解：不能满足要求。设A前置放大器，B为输入级，C为下一级。PsiPni105F?1F?110?11.995?1Fn??4?FnA?nB?nC?FnA???FnA?8.1PsoPno10ApAApA?ApB1010?0.15?8解：i?kv?k?V0?Vmcos?0t?2

21212???k?V02?2V0Vmcos?0t?Vm?Vmcos22?0t?22??当Vm??V0时，i?k?V02?2V0Vmcos?0t?，该非线性元件就能近似当成线性元件来处理，即当V0较大时，静态工作点选在抛物线上段接近线性部分，然后当Vm很小时，根据泰勒级数原则，可认为信号电压在特性的线性范围内变化，不会进入曲线弯曲部分，故可只取其级数的前两项得到近似线性特性。5?12解：为了使iC中的二次谐波振幅达到最大值，?C应为60o。cos60o?VBZ?VBB1?Vm21?VBB?Vm?VBZ2

?gVcos?t5?13解：i??m?0i??Incosn?tn?0?当cos?t?0当cos?t?01??1??gVcos?td?t?gVm2?????m1??1I1??gVmcos2?td??t??gVm???21?21???gVm2In??gVmcos?tcosn?td??t????n?1?????05?15解：i?iD1?iD2I0?n为偶数n为奇数

?gVcos?tiD1??m?024?当cos?t?0当cos?t?0?gVcos?tiD2??m?0当cos?t?0当cos?t?0k?1??1??k?1,2,3,??i?gVm?gVm?cos2k?0t2??k?1?2k??15?16解：当V0?1?msin?t?sin?0t?0时，i?0；当V0?1?msin?t?sin?0t?0时，i?gV0?1?msin?t?sin?0t

5?17解：v0?RL?iD1?iD2??RLk?v1?v2??k?v1?v2??4kRLv1v2

5?18解：v0?RL?i2?i3??RL?i4?i1??RL?i2?i4?i1?i3?22??cos2kω0tsinΩtcos2kω0t??i?gV0?1?msinΩt?2??2m??22?4k?14k?1k?1k?1???k?1,2,3,??

2????R?b?R?b?R?bLLL?RLb0?b1?v1?v2??b2?v1?v2??b3?v1?v2?2203??b1??v1?v2??b2??v1?v2??b3??v1?v2??b1?v1?v2??b2?v1?v2??b3?v1?v2?223300???

?b1??v1?v2??b2??v1?v2??b3??v1?v2?3??8RLb2v1v2?1?gm?5?23解：diC23?b1?2b2vBE?3b3vBE?4b4vBEdvBEdiCdvBE?b1?2b2V0mcos?0t?3b3V02mcos2?0t?4b4V03mcos3?0tvBE?v0gm?t???b1?2b2V0mcos?0t?gm1?2b2V0m?3b4V03m3b3V02m?1?cos2?0??2b4V03mcos?0t?b4V03m?cos?0t?cos3?0t?21gm1?b2V0m?1.5b4V03m2qvBEdiCaISq?2?gm??vBE?ekTdvBEkTgc?digm?t??CdvBEVomcos?0taIq?SVomcos?0t?ekTkTqvBE?v023??aISqq1?q1?q???Vomcos?0t?1?Vomcos?0t??Vomcos?0t???Vomcos?0t????kT2?kT6?kT?????kT?qV?I?qV??I?qV??qV???ISomcos?0t??IS?om?cos2?0t?S?om?cos3?0t?S?om?cos4?0tkT2?kT?6?kT??kT?gm1qV3?IS?qVom???ISom???kT8?kT?3234?IqV3?IS1gc?gm1?Som?22kT165?25解：i??i1?i3?i2?i4?qVom????kT?23?a0?a1?v0?vs??a2?v0?vs??a3?v0?vs??a4?v0?vs???34?a0?a1?v0?vs??a2?v0?vs??a3?v0?vs??a4?v0?vs???234?a0?a1??v0?vs??a2??v0?vs??a3??v0?vs??a4??v0?vs???234?a0?a1??v0?vs??a2??v0?vs??a3??v0?vs??a4??v0?vs???2343?8a2v0vs?16a4v0vs?16a4vs3v0??

5?29解：gc?0.5IE262?gic?gb?e??sIE?1???r??26bb????T?I0.5?E??0.55?mS?26?026?350.5IE0.5?0.5??9.6?mS?2626goc?gce?4??S?Apcmax2gc9.62??40dB????104734gicgoc4?0.55?0.004222???QL?2fi?2?465??????30.1dB?Apc?Apcmax??1?Q???Apcmax?1?Q2?f??10473??1?100?10???12280?00.7?????IE260.5IE0.5?0.085?30解：gc?0.5???1.54?mS?22626??sIE?1?????26rbb????T?I0.08gic?gb?e?E??0.1?mS?26?026?30goc?gce?10??S?Apcmax2gc1.542???592.9??28dB?4gicgoc4?0.1?0.0122?gc?GL?1.54?0.1Apc???g?G???g??0.01?0.1??0.1?196??23dB???L?ic?oc

5?32解：i??i1?i2?i3?i4???a??a?a0?a1?v0?vs??a2?v0?vs??a3?v0?vs??a4?v0?vs???23423423?a0?a1?v0?vs??a2?v0?vs??a3?v0?vs??a4?v0?vs???0023?44?a1??v0?vs??a2??v0?vs??a3??v0?vs??a4??v0?vs????a1??v0?vs??a2??v0?vs??a3??v0?vs??a4??v0?vs?????3?8a2v0vs?16a4v0vs?16a4vs3v0??

5?34解：因存在二次项，能进行混频。只要满足fn?fi就会产生中频干扰；当fn?f0?fi时产生镜像干扰。由于不存在三次项，不会产生交调干扰；有二次项，可能产生互调干扰；若有强干扰信号，则能产生阻塞干扰。

5?35解：1.此现象属于组合频率干扰。这是由于混频器的输出电流中，除需要的中频电流外，还存在一些谐波频率和组合频率，如果这些组合频率接近于中频放大的通带内，它就能和有用中频一道进入中频放大器，并被放大后加到检波器上，通过检波器的非线性效应，与中频差拍检波，产生音频，最终出现哨叫声。2.因fi?465kHz，p、q为本振和信号的谐波次数，不考虑大于3的情况。所以落于535~1605kHz波段内的干扰在fS?930kHz和fS?1395kHz附近，1kHz的哨叫声在929kHz、931kHz、1394kHz、1396kHz时产生。3.提高前端电路的选择性，合理选择中频等。5?36解：若满足?pf1?qf2?fs，则会产生互调干扰：?MHz?，不会产生互调干扰；p?1、q?1，f1?f2?774?1035?1.809?MHz?，会产生互调干扰；p?1、q?2，f1?2f2?774?2?1035?2.844?MHz?，会产生互调干扰；p?2、q?1，2f1?f2?2?774?1035?2.583?MHz?，会产生互调干扰；p?2、q?2，2?f1?f2??2??774?1035??3.618?MHz?，会产生互调干扰；p?2、q?3，2f1?3f2?2?774?3?1035?4.653?MHz?，会产生互调干扰；p?3、q?2，3f1?2f2?3?774?2?1035?4.392?MHz?，会产生互调干扰；p?3、q?3，3?f1?f2??3??774?1035??5.427p、q大于3谐波较小，可以不考虑。?3f?2f0?2?1??S5?37解：?fS?f0?0.8?MHz??2fS?3f0?2??fS?2f0?2??fS?f0?0.4?MHz???2f?3f?2S0??fS?0.2MHzf0?0.6MHz

?2????3fs?2f0?30??fs?f0?12?MHz??2f?3f?30s0??fs?2f0?30?fs?f0?20?MHz???2fs?f0?30?fS?4MHzf0?16MHz

5?39解：若满足?pf1?qf2?fs，则会产生互调干扰。已知f1?19.6MHz、f2?19.2MHz、fs?f0?fi?23?3?20?MHz?，故没有互调信号输出。

6?4解：P??VCCICO?24?0.25?6?W??C?P05??83.3%P?622VcmVCC242Rp????57.6???2P02P02?5Icm1?2P02P02?5???0.417?A?VcmVCC24Icm10.42??1.67Ic00.25gc??c??查表得?c?77o

2ηVCC2?0.7?126?6解：gc?θc????1.56查表得θc?91oVcm10.8P0?Ik2R?22?1?4?W??1??1??PC?P??P0???1P??1???4?1.7?W?0?η??0.7??c?Ic0906?7解：icmax???282?mA?oα0900.319

Ic1mP0????α?90?io1cmax?mA??0.5?282?14111RpIc21m??200?0.1412?2?W?22P02ηc???74%VCCIc030?0.09

22222VcmIkmR2???0L?IkmR2???0L?RCIkmR2???0L?RIkmR6?8证：P0?????22L2RP2L22??0L?RC

i2.26?9解：Vcm?VCC?vcmin?VCC?cmax?24??21.25?V?gcr0.8222??????Ic0?icmax?0?70o??2.2?0.253?0.5566?A?Icm1?icmax?1?70o??2.2?0.436?0.9592?A?P??VCCIc0?24?0.5566?13.36?W?11P0?VcmIcm1??21.25?0.9592?10.19?W?22PC?P??P0?13.36?10.19?3.17?W??C?P010.19??76.3%P?13.36

2Vcm21.252Rp???22.16???2P02?10.19

22VcmVCC2426?10解：R1?Rp????144???2P02P02?2XC1?C1?R1144??14.4???QL1011?pF???22162?fXC12?3.14?50?10?14.4R2R22?QL?1??1R1?200200??100?1??1144?16.95???XL1?L1?XL116.95??0.054??H?62?f2?3.14?50?102?1?RP增加一倍，放大器工作6?11解：于过压状态，Vcm变化不大，P0??Vcm/2RP?0.5P0；2?2?RP减小一半，放大器工作于欠压状态，Icm变化不大，P0??IcmRP/2?2P0。?10?144?QLR1?R2200????1??1???2.57???2??QL?1?QLXL1?100?1?10?16.95?11?pF?C2???12392?fXC22?3.14?50?106?2.57 XC2?6?12解：?k?r???r1?r1?

22?VCC?VCE?sat??Vcm?12?0.5?6?13解：RP????66???2P02P02?12111???57.4%?L1?L2111?1?22QQk100?15?0.032Q1Q2??M?12

设QL?10C1?则XC1?RP66??6.6???QL1011??241?pF?2?fXC12?3.14?108?6.6RLR?1?Q?R2LLXC2???150P?1?10??50?1662?5.5???C2?11??290?pF?2?fXC22?3.14?108?5.5QLRP?RL?10?66?50???1??1?2?102?1?10?5.5??12.5???QL?1?QX??LC2??

XL1?L1?XL112.5??19.9?nH?82?f2?3.14?10?C1?和R???a?将R1C1和R2C2串联电路改为R16?14证：XC1?2C2并联电路，并设2XCR1??212R1R1?XC12XC??222R2R2R2?XC2R1QL2R2?2?2XCXC22R2?XC2R12?1?2XCXC12R1?XC122XCXC11?，即R1??2匹配时R1??R2R1?R1?222R222R1?XC11?QLR2?XC2?XC2?R2?1?Q?RR2L2?11XL12R12R2?1?XC?2?2?XCXC1?2XC222R1?XC1R2?XC22XCR12R1R2R1QL1R1R2R1QL1?2X??????C122222R1?XCR12?XCXC21?QL1?QLXC21?QL11?R2??1??QX??LC2???C1?和R???b?将R1C1和R2L1串联电路改为R1XC1?2L1并联电路，并设2XCR1??212R1R1?XC12XL1??2R2R22R2?XL1R1QL2R2??2XL1XL12R2?XL1R12?1?2XCXC12R1?XC122XC1XL11?，即R1??2匹配时R1??R2R1?R1?2R2222R1?XC11?QLR2?XL1?XL1?R2?1?Q?RR2L2?11XC22R2R12?1?XC?1?2?XLXL1?2XC122R2?XL1R1?XC12XCRRRQRQR2RQRQ?212?12?1L2?1L2??1L2?1L2R1?XC1XL11?QL1?QLQLXL11?QL1?QL?R2????1?QX??LL1??1?天线断开，工作于过压6?18解：状态，集电极直流电表读数减小，天线电流表读数为0；?2?天线接地，工作于欠压状态，集电极直流电表读数略增，天线电流表读数增加；?3?中介回路失谐，工作于欠压状态，集电极直流电表读数略增，天线电流表读数减小。?1?PA?P??PC?Pk?10?3?1?6?W?6?19解：?2??k?PA6??85.7%P??PC10?3P??10?3?70?3??c?P??PC??PA6??60%P?10

6?20解：当k?kc时，?k?1???1?若?k6?25解：

r1?50%则r??r1r1?r?1?Q1Q2kc?1Q01QQ09?3?3kcQ

r1?90%则r???9r1故k?r1?r??

6?27解：??2?60o???1?60o?，?P0减小，工作于欠压状态。

VV6?28解：Ri??93?9RLI3I

V?VBB0.6?1.456?29解：Vbm?BZ??6?V?ocos?cos70VB?Vbm?VBB?6?1.45?4.55?V?iCmax?Icm1P0?VB?VBZ4.55?0.6??1.98?A?22?iCmax?1?70o??1.98?0.436?0.86?A?Vcm?VCC?gcriCmax?24?1.98?22.02?V?Icm1Vcm0.86?22.01??9.47?W?22?QL?10???PA??1?P?1????9.47?8.52?W?0??Q0??100??

6?30解：Vbm?VBZ?VBB0.6?1.5??6.14?V?cos?cos70oVB?Vbm?VBB?6.14?1.5?4.64?V?iCmax?Icm1P0?VB?VBZ4.64?0.6??2.02?A?22?iCmax?1?70o??2.02?0.436?0.88?A?Vcm??VCC?0.9?24?21.6?V?Icm1Vcm0.88?21.6??9.5?W?22?QL?10???PA??1?P?1????9.5?8.8?W??Q?0100??0??

?a?电路可能振荡，属于电7?5解：感反馈式振荡电路；?e?电路可能振荡，属于电容反馈式振荡电路；?h?电路可能振荡，属于电容反馈式振荡电路；?b?、?c?、?d?电路不可能振荡；?f?电路在L2C2?L3C3时有可能振荡，属于电容反馈式振荡电路?g?电路计及Cbe可能振荡，属于电容反馈式振荡电路。 ?1?有可能振荡，属于电容7?6解：反馈式振荡电路，f1?f2?f0?f3；?2?有可能振荡，属于电感反馈式振荡电路，f1?f2?f0?f3；?4?有可能振荡；属于电容反馈式振荡电路，f1?f2?f0?f3；?3??5??6?不可能。

7?7解：

?1?f0?7?21解：11??100?MHz??7?122πL?C?Cd?2?3.14?10??20?5??10C1??L36?2?gd?1?1RPQ?3?0.06~0.08V?1?fq?7?26解：6?20?5??10?1210?7?5.27?mS?

?1?1.5~1.5001?MHz?7?27解：1.657?101.657?10??4.14?MHz?d0.4S200Cq?21.1?10?5?21.1?10?5??0.105?pF?d0.4d30.43Lq?43.5?43.5??14?mH?S200d0.4rd?42500B?42500?0.25??21.2?Ω?S200S200C0?3.96?10?2?3.96?10?2??19.8?pF?d0.41.051.05Qq??104d??104?0.4?16800B0.251.657?1061.657?106?2?d???0.11?mm?6fq15?10

?2?不能?3?不能，普通三极管没有负阻特性。

7?28解：恒温槽、稳压电源、高稳定度克拉泼振荡电路、共集电极缓冲级等。

7?29解：并联c?b型（皮尔斯）晶体振荡电路。

9?3解：i?I?1?macosΩt?cosω0t?Icosω0t?I有效值IImacos?ω0?Ω?t?macos?ω0?Ω?t22222?I??I??I???ma???ma?????2??22??22?2maI?1?22

?1?v?25?1?0.7cos2π5000t?0.3cos2π100009?4解：t?sin2π106t??25sin2π106t?8.75?sin2π1005000?sin2π995000??3.75?sin2π1010000?sin2π990000?2?包络25?1?0.7cos2π5000t?0.3cos2π10000t?V?V025??1?0.7?0.3??25峰值调幅度m?max??0.4上V025V0?Vmin25?25?1?0.7?0.3???1V025

121?1?ma?1时9?5解：P?ω0?Ω??P?ω0?Ω??maP0T??100?25?W?44121?2?ma?0.3时P?ω0?Ω??P?ω0?Ω??maP0T??0.32?100?2.25?W?44

39?6解：i?b1v?b3v不包含平方项，不能产生调幅作用。

?1?P?ω0?Ω??P?ω0?Ω??1ma2P0T?1?0.72?5000?612.5?W?9?7解：44?W?P?ω0?Ω??2P?ω0?Ω??1225谷值调幅度m下??2?P??P0avη?P0T5000??10?kW?η0.52???ma0.72??P0T?1???5000???1?2??2P0av?????12.45?kW??3?P????ηη0.5

?1?ma?1时9?8解：121maP0T??1000?250?W?44?W?P0?P0T?P?ω0?Ω??P?ω0?Ω??1000?250?250?1500P?ω0?Ω??P?ω0?Ω???2?ma?0.7时121maP0T??0.72?1000?122.5?W?44?W?P0?P0T?P?ω0?Ω??P?ω0?Ω??1000?122.5?122.5?1245P?ω0?Ω??P?ω0?Ω???kHz? 9?9解：f?f0?f1?f2?f3?f4?5?20?200?1780?8000?10005

9?10解：i1?b0?b1?v?vΩ??b2?v?vΩ??b3?v?vΩ?23i2?b0?b1?v?vΩ??b2?v?vΩ??b3?v?vΩ?233v0??i1?i2?R?R2b1vΩ?4b2vvΩ?6b3v2vΩ?2b3vΩ??3?2b1RVΩcosΩt?3b3RV02VΩcosΩt?1.5b3RVΩcosΩt?2b2RV0VΩcos?ω0?Ω?t?2b2RV0VΩcos?ω0?Ω?t?1.5b3RV02VΩcos?2ω0?Ω?t?1.5b3RV02VΩcos?2ω0?Ω?t3?0.5b3RVΩcos3Ωt

输出端的频率分量：?、3?、?0??、2?0??

?P0??10.125??9?12解：m1?2??1?2??1??0.5??P?9???0T?121P0??P0?m2P0T?10.125??0.42?9?10.845?kW?22

9?13?1?vA?t??v??t??V?cos?tvB?t??v?t??2?若D1D2开路，则vA?t??vB?t??v??t?vAB?0?3?若D1D2短路，则vA?t??v??t??V?cos?tvB?0vAB?t??V?cos?t9?18解：R??R1?3R2ri24700?1000????510??1335R2?ri24700?10003?Rd33?3.14?100????0.57R510?4700Kd?cos??0.87V??KdmaVim?0.87?0.3?0.5?0.132V?0.132P????6.33??W?2R?2?133522VimVimKd0.52?0.87P?????41.7??W?2RidR510?4700AP?P?6.33??0.152P?41.7R??R?R1?R22?R22?ri22350?1000510?2350?R22?ri22350?1000?0.55?R1?R2510?4700?1?中间位置9?19解：?2?最高端R?RR1?R2ri24700?1000510?R2?ri24700?1000?0.26?R1?R2510?4700

?R2的触点在中间位置会产生负峰切割失真，而在最高端不会。9?20解：由R?R1?R2??5~10?k??11?R1??~?R2?510?取R2?6k?R1?1.5k?R2ri26?2R??R1??1.5??3?k??R2?ri26?2R?31ma???R93取ma?0.31-ma21?0.32C???0.0187??F?maR?max0.3?9000?2?3.14?30001Ce????0.26??F??minri22?3.14?300?20003?Rd33?3.14?100????0.5R6000?1500Kd?cos??0.93取C1?C2?0.01?F1取Ce?20?FR9000Rid???5?k??能满足要求2Kd2?0.9

?0C2?3.14?465?103?200?10?129?21解：GP???5.84??S?Q0100f0465QL???23.52?f0.720Q0?100??622GP?p24goe?GP?5.84?0.3?100?5.84??10?QL23.5??p34???0.1532gid4700

i?kmV?1tV0cos??0t???1cos?tcos1?kmVcos???1??0???t????cos???1??0???t???1V0?4?cos???1??0???t????cos???1??0???t????11当?0??1时，vS?kmRLV1V0?cos??t????cos??t?????kmRLV1V0cos?cos?t42无失真，?只影响输出幅度。1当?0??1时，vS?kmRLV1V0cos???1??0?t???cos?t2有失真。?1?v1?mV1cos?tcos?1t9?24解：?2?v1?1mV1cos??1???t21i?kmV1cos??1???tV0cos??0t???21?kmVcos???1??0???t????cos???1??0???t????1V0?41vS?kmRLV1V0cos???1??0???t???4当?0??1时，?只产生相移；当?0??1时，有失真。

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