Umisiri, Zamagetsi
Gawo kusinthasintha mawu monga njira kufala deta
Monga amadziwika, ndi RF chizindikiro tichipeza chonyamulira, amene zochokera mphepo mu mawonekedwe a yosavuta amgwirizano oscillation u (T) = U Ko ( ωt + φ). Kuchokera pamenepa, ndizoonekeratu kuti chonyamulira pafupipafupi chizindikiro, pali atatu palokha magawo, okhudza amaonekera chimene chikhoza kusintha ulamuliro chizindikiro.
Izi zikutanthauza kuti n'zotheka mitundu itatu: matalikidwe (AM), pafupipafupi (FM) ndi gawo kusinthasintha mawu (PM).
Gawo kusinthasintha mawu - njira za kupatsira analogi kapena mfundo digito ndi kusintha mbali koyamba (gawo) φ 0 chonyamulira pafupipafupi mbendera opatsirana.
Pamene gawo φ (T) zimadalira matalikidwe kulamulira (kusinthasintha mawu) chizindikiro i.e., φ (T) = ω 0 T + Δ φ ∙ sinΩt + φ 0 = = φ 0 + ke (T), kumene K - Kugwirizana china.
Mbendera gawo-modulated ambiri anafotokozedwa ndi mawu u (T) = U N tchimo [ωt + φ (T)].
Pamene mmodzi kamvekedwe kusinthasintha mawu [e (T) = E tchimo Ωt] tili: φ (T) = φ 0 + ke tchimo Ωt = φ 0 + Δφ Max tchimo Ωt.
Pambuyo m'malo mfundo za φ (T) mu aone kuti pali mbendera gawo-modulated timapeza u (T) = U N tchimo (ω N T + φ 0 + Δφ Max tchimo Ωt), kumene Δφ Max - kusintha pazipita mu gawo molingana ndi matalikidwe a ulamuliro voteji. Δφ Max mwinamwake otchedwa ngodya kusinthasintha mawu index ndipo amaimira m.
Monga mmene taonera, pamene FM mamita = Δφ Max = ke. Mtengo yomweyo ya nthawi-osiyanasiyana gawo ngodya Θ (T) ndi wofanana Θ (T) = ω N T + φ 0 + msin Ωt, kotero kuti ω = D Θ (T) / Deuteronomo = ω N + mΩ cosΩt, mmene mΩ = Δφ Max ω = δ ω N = kEΩ - pazipita pafupipafupi kupatuka kwa FM ω N, ndi mwachindunji njila kwa matalikidwe ndi pafupipafupi wa oscillation modulating.
Choncho, pamene FM kusinthasintha mawu index amakhala pazipita gawo kusintha molingana ndi matalikidwe kulamulira chizindikiro ndiponso sikudalira pa kusinthasintha mawu pafupipafupi. Pafupipafupi kusintha za zikutanthauza (zopatuka) mwachindunji njila kwa matalikidwe ndi pafupipafupi wa modulating voteji.
Malinga ndi ntchito gawo kusinthasintha mawu ali mitundu angapo. Mmodzi wa iwo, makamaka, ndi masiyanidwe fezi Kaonedwe Keying.
Mu njira imeneyi, malinga ndi modulating chizindikiro zimasiyanasiyana yekha gawo la chizindikiro, ndipo pafupipafupi ndi matalikidwe sizisintha. Pamene mtengo rpm mudziwe si Mtheradi gawo kusintha, ndi kusintha kwake ndi kulemekeza mfundo za m'mbuyomo.
Pakompyuta dera, zomwe zimabweretsa kusintha gawo ngodya ya oscillation modulated (wachibale chonyamulira unmodulated) mogwirizana ndi modulating chizindikiro amatchedwa gawo modulator.
Yopangidwa osiyanasiyana zithunzi. Chiwembu yosavuta modulator zizindikiro varicap - diode waluso pa zotsatira za kusintha ulamuliro voteji mphambano capacitance. Mu chiwembu ichi, modulating ndi voteji chimasintha mphamvu varicap lapansi. Gawo kosangalatsa zimadalira ukulu wachibale wa capacitance diode ndi katundu kukana R.
Choncho, amasinthira chimadalira pa kusinthasintha mawu voteji. Izi zimapangitsa gawo kusinthasintha mawu a mbendera wailesi. Komabe, kusinthaku amagwirizana ndi osalunjika modulating voteji varicap capacitance chokhudzana ndi osalunjika modulating voteji kuti kumaonjezera mavuto ena mu modulators yomanga gawo.
Koyera gawo kusinthasintha mawu ali sanapeze ntchito mokwanira lonse chifukwa cha lalikulu sangathe ake chibadidwe - otsika phokoso chitetezo chokwanira.
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