5?8解:i?kv2?k?V0?Vmcos?0t?21212?2?2?k?V0?2V0Vmcos?0t?Vm?Vmcos2?0t?22??当Vm??V0时,i?k?V0?2V0Vmcos?0t?,该非线性元件就能近2似当成线性元件来处理Vm很小时,根据泰线弯曲部分,故,即当V0较大时,静态工作点选勒级数原则,可认为信可只取其级数的前两项在抛物线上段接近线性部分,然后当号电压在特性的线性范得到近似线性特性。围内变化,不会进入曲o5?12解:为了使cos60oiC中的二次谐波振幅达到?VBZ?VBBVm?12最大值,?C应为60。12Vm?VBZ?VBB?
?gVmcos?t5?13解:i???0?当cos?t?0当cos?t?0i??In?0ncosn?tI0?I1?12?1????????gVmcos?td??t??21?12gVmgVmn为偶数n为奇数?1???gVmcos?td??t??In??????gVm1?2?gVm2cos?tcosn?td??t????n?1??0当cos?t?0当cos?t?0?
5?15解:i?iD1?iD2?gVmcos?tiD1???024?gVmcos?tiD2???0当cos?t?0当cos?t?0??1?k?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??cos2kω0tsinΩtcos2kω0t??i?gV0?1?msinΩt?2??2m??22?4k?14k?1k?1k?1??
2?k?1,2,3,??5?17解:v0?RL?iD1?iD2??RLk?v1?v2??k?v1?v2?2?2??4kR3
Lv1v25?18解:v0?RL?i2?i3??RL?i4?i1??RL?i2?i4?i1?i3??RLb0?b1?v1?v2??b2?v1?v2??b3?v1?v2?2
?RL?RL?RL??b?b?b3???
000?b1??v1?v2??b2??v1?v2??b3??v1?v2?2?b1?v1?v2??b2?v1?v2??b3?v1?v2?223?3?b1??v1?v2??b2??v1?v2??b3??v1?v2???8RLb2v1v2?1?gm?5?23解:diCdvBE?b1?2b2vBE?3b3vBE?4b4vBE?b1?2b2V0mcos?0t?3b3V0mcos?0t?4b4V0mcos?0tvBE?v0223323gm?t??diCdvBE?b1?2b2V0mcos?0t?gm1?2b2V0m?3b4V0mgc?12332b3V0m?1?cos2?0??2b4V0mcos?0t?b4V0m?cos?0t?cos3?0t?233gm1?b2V0m?1.5b4V0m?aISqkTq3?2?gm?diCdvBEvBE?ekT?aISqkTvBEgm?t??aISqkTdiCdvBEVomvBE?v0qVomcos?0t?ekTVomcos?0t?23??q1?q1?q??cos?0t?1?Vomcos?0t??Vomcos?0t???Vomcos?0t????kT2?kT6?kT????????ISqVomkT?IS?qVom??IS?qVom??qVom?234cos?0t??IS??cos?0t???cos?0t???cos?0t2?kT?6?kT??kT?kT3?IS?qVom????8?kT?3234gm1??IS12qVomgc?gm1??ISqVom2kT3?IS?qVom????16?kT?235?25解:i??i1?i3?i2?i4?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???234?8a2v0vs?16a4v0vs?16a4vsv0??33
5?29解:gc?0.5IE26??sIE??1???rbb?????T26?2?0.5IE26?0.5?0.526?9.6?mS?gic?gb?e?IE26?02?0.526?35?0.55?mS?goc?gce?4??S?Apcmax?gc4gicgoc?9.6224?0.55?0.004?10473??40dB2????1228??30.1dB??2Apc?QL???Apcmax?Apcmax?1??Q0???IE26??sIE??1???rbb?????T26?25?30解:gc?0.5??2fi?2?465?1???10473??1???Q02?f0.7?100?10???0.5IE0.5?0.08???1.54?mS?2626?gic?gb?e?IE26?02?0.0826?30?0.1?mS?goc?gce?10??S?Apcmax?gc4gicgoc?21.5424?0.1?0.01?592.9??28dB2??
4Apc?gc???g?GL?oc?GL0.1?1.54??????196??23dB???g0.1?0.01?0.1?ic?235?32解:i??i1?i2?i3?i4?a0?a1?v0?vs??a2?v0?vs??a3?v0?vs??a4?v0?vs??????a??a?a0?a1?v0?vs??a2?v0?vs??a3?v0?vs??a4?v0?vs???2342300?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?2333???? fn?f0?fi,可能产生?8a2v0vs?16a4v0vs?16a4vsv0??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;当生交调干扰;有二次项扰。时产生镜像干扰。由于互调干扰;若有强干扰不存在三次项,不会产信号,则能产生阻塞干
5?35解:1.此现象属于组合频率干还存在一些谐波频率和它就能和有用中频一道的非线性效应,与中频扰。这是由于混频器的组合频率,如果这些组进入中频放大器,并被差拍检波,产生音频,输出电流中,除需要的合频率接近于中频放大放大后加到检波器上,最终出现哨叫声。数,不考虑大于中频电流外,的通带内,通过检波器2.因fi?465kHz,p、q为本振和信号的谐波次~1605kHz波段内的干扰在931kHz、1394kHz、1396kHz时产生。3.提高前端电路的选择性,合理选择中频等。3的情况。所以落于535fS?930kHz和fS?1395kHz附近,1kHz的哨叫声在929kHz、5?36解:若满足?pf1?qf2?fs,则会产生互调干扰:p?1、q?1,f1?f2?774?1035?1.809?MHz?,不会产生互调干扰;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?1035p、q大于3谐波较小,可以不考虑。??5.427?MHz?,会产生互调干扰;
?1?5?37解:?3fS?2f0?2?fS?f0?0.8?MHz?2f?3f?20?S????fS?2f0?2??fS?f0?0.4?MHz???2fS?3f0?2?fS?0.2MHzf0?0.6MHz??3fs?2f0?30??2fs?3f0?30?2????fs?f0?12?MHz??fs?2f0?30?fs?f0?20?MHz?2f?f?300?s?fS?4MHz5?39解:若满足?
已知f1?19.6MHz、。f0?16MHz?pf1?qf2?fs,则会产生互调干扰。f2?19.2MHz、fs?f0?fi?23?3?20?MHz?,故没有互调信号输出