4.1ᓩ㿔㄀㄀㄀4ゴゴゴ῵ᢳ䇗ࠊ㋏㒳MOD(ᓩ㿔ᓩ㿔ᓩ㿔䇗ࠊֵোmt)(Ꮖ䇗ֵsm(t4.14.2䇗ᐙ䇗ᐙ䇗ᐙ˄䇗ᐙ˄˄˄AM˅˅˅Ϣঠ䖍ᏺ˅Ϣঠ䖍ᏺ˄˄˄DSB˅˅˅䇗ࠊ˅䇗ࠊ(䕑⊶ֵs(t4.3ऩ䖍ᏺ˄˄˄SSB˅˅˅Ϣ⅟⬭䖍ᏺ˅Ϣ⅟⬭䖍ᏺ˄˄˄VSB˅˅˅䇗ࠊ˅䇗ࠊ(䕑⊶ֵো䕑⊶ֵো˖˖˖˖st)(=Acos(ωt+ϕ4.4ᐙᑺ䇗ࠊ㋏㒳ⱘᡫాໄᗻ㛑c0㾦ᑺ䇗ࠊ䇗ᐙֵো䇗ᐙֵো˖˖˖˖䕑⊶ⱘᐙᑺ䱣䇗ࠊֵোਜ㒓ᗻ݇㋏ব࣪䕑⊶ⱘᐙᑺ䱣䇗ࠊֵোਜ㒓ᗻ݇㋏ব࣪䕑⊶ⱘᐙᑺ䱣䇗ࠊֵোਜ㒓ᗻ݇㋏ব࣪ˈˈˈˈ乥⥛ঞⳌ乥⥛ঞⳌ4.5ԡ≵᳝ᬍবԡ≵᳝ᬍব˗˗˗˗䇗乥ֵোⱘᡫాໄᗻ㛑4.6乥⥛ֵো乥⥛ֵো˖˖˖˖䕑⊶ⱘ乥⥛䱣䇗ࠊֵোਜ㒓ᗻ݇㋏ব࣪䕑⊶ⱘ乥⥛䱣䇗ࠊֵোਜ㒓ᗻ݇㋏ব࣪䕑⊶ⱘ乥⥛䱣䇗ࠊֵোਜ㒓ᗻ݇㋏ব࣪ˈˈˈˈᐙᑺঞⳌᐙᑺঞⳌ4.7৘⾡῵ᢳ䇗ࠊ㋏㒳ⱘ↨䕗ԡ≵᳝ᬍবԡ≵᳝ᬍব˗˗˗˗乥ߚ໡⫼ঞᑨ⫼ᅲ՟ⳌԡֵোⳌԡֵো˖˖˖˖䕑⊶ⱘⳌԡ䱣䇗ࠊֵোਜ㒓ᗻ݇㋏ব࣪䕑⊶ⱘⳌԡ䱣䇗ࠊֵোਜ㒓ᗻ݇㋏ব࣪䕑⊶ⱘⳌԡ䱣䇗ࠊֵোਜ㒓ᗻ݇㋏ব࣪ˈˈˈˈᐙᑺঞ乥ᐙᑺঞ乥4.8⥛≵᳝ᬍব⥛≵᳝ᬍব˗˗˗˗4.2䇗ᐙ䇗ᐙ䇗ᐙ˄䇗ᐙ˄˄˄AM˅˅˅Ϣঠ䖍ᏺ˅Ϣঠ䖍ᏺ˄˄˄DSB˅˅˅䇗ࠊ˅䇗ࠊᐙᑺ䇗ࠊ఼ⱘϔ㠀῵ൟЎҔМ㽕䇗ࠊ䖯㸠䕑⊶䇗ࠊ˛˛˛m(t)×h(t)sm(t)䇗ࠊֵো1ǃǃǃ᮴㒓Ӵ䕧Ёǃ᮴㒓Ӵ䕧ЁˈˈˈЎ՟㦋ᕫ䕗催ⱘ䕤ᇘᬜ⥛ˈЎ՟㦋ᕫ䕗催ⱘ䕤ᇘᬜ⥛ˈˈˈ㽕ˈ㽕㽕㽕Ꮖ䇗⊶ᔶcosωt∖໽㒓໻Ѣ¬¬¬/4DŽDŽDŽ䕑⊶䕑⊶䕑⊶c՟བ՟བ՟བ˖՟བ˖˖˖3000Hzⱘ෎ᏺֵোˈˈˈ䳔㽕ˈ䳔㽕25Kmⱘ໽㒓DŽDŽDŽs(t:)h(t)ᰃܼ䗮Ⓒ⊶఼900MHz乥↉ˈˈˈ䳔㽕ˈ䳔㽕8cmⱘ໽㒓DŽDŽDŽAMs(t:)h(t)ᰃܼ䗮Ⓒ⊶఼s(t)DSB2ǃǃǃᅲ⦄໮䏃໡⫼ǃᅲ⦄໮䏃໡⫼DŽDŽDŽmsSSBt:)(h(t)䖍ᏺⒸ⊶఼3ǃǃǃᅲ⦄Ӵ䕧ᏺᆑϢֵా↨П䯈ⱘѦᤶǃᅲ⦄Ӵ䕧ᏺᆑϢֵా↨П䯈ⱘѦᤶDŽDŽDŽsVSBt:)(h(t)⅟⬭䖍ᏺⒸ⊶఼s(t)m(t)×h(t)sm(t)m(t)AMˇm(t)=0cosωtcωA0cosct=ω+ϕst)(Acos(ct)AM䇗ࠊ఼῵ൟ=ω䴲䴲䴲㒓ᗻবᤶ䴲㒓ᗻবᤶsm(t)Am(t)cosct=+ω=ω+ωsAM(t)[A0m(t)]cosctA0cosctm(t)cosctω=Aω+ω+ω−ωSm()[M(c)M(c)]㒓ᗻ䇗ࠊ2䕑⊶ߚ䞣䖍ᏺߚ䞣4.2.1䇗ᐙ⊶ⱘᯊඳߚᵤ1ǂֵোⱘᯊඳ⊶ᔶ=+ωAMsAM(t)[A0m(t)]cosctβ<AM1m(t)OtA0ˇm(t)m(t)β=maxAMA0Otωcosc(t)Otβ≤AM:1㒓ᗻ䇗ᐙsAM(t)β>O:1䖛䇗ᐙtAMβ=β>1AM1AM4.2.2䇗ᐙ⊶ⱘ乥䈅ω=πδω−ω+δω+ω+1[]ω−ω+ω+ωSAM()A0[(c)(c)]M(c)M(c)2乥䈅೒⡍⚍乥䈅೒⡍⚍˖˖˖˖M(ω)ᯊඳ⊶ᔶ⡍⚍ᯊඳ⊶ᔶ⡍⚍˖˖˖˖1m(t)OtˉωωωH0H1˅˅˅㒓ᗻ䇗ᐙ˅㒓ᗻ䇗ᐙ㒓ᗻ䇗ᐙ˖˖˖˖ࣙ㒰䱣ࣙ㒰䱣1˅˅˅Ϟ˅ϞϞϞǃǃǃǃϟ䖍ᏺഛࣙ৿њϟ䖍ᏺഛࣙ৿њ䇗ࠊֵোਜ㒓ᗻ݇㋏ব෎ᏺֵোⱘܼ䚼ֵᙃ෎ᏺֵোⱘܼ䚼ֵᙃDŽDŽDŽDŽC(ω)ππ࣪࣪࣪DŽ࣪DŽDŽDŽס乥ᏺࡴסञˈˈˈˈ乥ᏺࡴޣञᐙᑺޣञ˅ᐙᑺޣωA0A0˅˅˅ᐙᑺcosc(t)2˅乥⥛᳾ব˅乥⥛᳾ব˖˖ҙЎ䇗ҙЎ䇗Oˉω0ωω2˅˅乥⥛᳾ব˖˖ҙЎ䇗tcc3˅˅˅㒓ᗻ䇗ࠊ˅㒓ᗻ䇗ࠊ㒓ᗻ䇗ࠊ˖˖˖˖Ꮖ䇗ֵোᏆ䇗ֵোˈˈˈˈ↨ᐙֵো੠䇗ࠊֵোⱘ乥䈅Ⳍ↨੠䇗ࠊֵোⱘ乥䈅Ⳍ3˅˅˅㒓ᗻ䇗ᐙⱘᴵӊ˅㒓ᗻ䇗ᐙⱘᴵӊ㒓ᗻ䇗ᐙⱘᴵӊ˖˖˖˖≵᳝ߎ⦄ᮄⱘ乥⥛ߚ䞣≵᳝ߎ⦄ᮄⱘ乥⥛ߚ䞣DŽωsAM(t)SAM()ππA0A0β≤1AM12Otˉω0ωωcc㒓ᗻ䇗ࠊ2䇗ᐙ⊶ⱘࡳ⥛ߚ䜡Ϣᬜ⥛⥛䇗ᐙ⊶ⱘࡳ⥛ߚ䜡Ϣᬜ⥛AMֵোⱘᬜ4.2.3=212PAMsAM(t)m(t)P2η=s=2=m(t)22AM=[A+m(t)]cosωtP12122+20cAMA+m(t)A0m(t)202=22ω+22ω+2ωA0cosctm(t)cosct2A0m(t)cosct=ω˖˖˖∖˖∖∖∖՟՟՟˖՟˖˖˖ᔧ䇗ࠊֵোЎऩ乥ԭᓺֵোेᔧ䇗ࠊֵোЎऩ乥ԭᓺֵোेm(t)AmcosmtA2m2(t)=0+=P+P1˅˅˅AMⱘᯊඳ㸼䖒ᓣⱘᯊඳ㸼䖒ᓣˈˈˈˈ⬏ߎᯊඳ⊶ᔶ⬏ߎᯊඳ⊶ᔶ⬏ߎᯊඳ⊶ᔶ˗˗˗