Isigaba ukushintshashintsha kwezwi njengoba indlela yokudlulisela idatha

Njengoba yaziwa, isiginali RF siqukethe yenethiwekhi, ogxile amagagasi omsakazo ngendlela elula oscillation harmonic u (t) = U cos ( ωt + φ). Kule kusobala ukuthi signal carrier imvamisa, kukhona imingcele ezimele ezintathu, ezithinta isinyathelo okungaba ukushintsha isignali control.

Lokhu kusho ukuthi kungenzeka ezintathu izinhlobo: amplitude (AM), imvamisa (FM) futhi isigaba ukushintshashintsha kwezwi (PM).

Isigaba ukushintshashintsha kwezwi - indlela yokudlulisela analog noma ulwazi digital ngokushintsha engela sokuqala (isigaba) φ ₀ imvamisa othwala isignali ngocansi.

Lapho-ke sengeta φ (t) kuncike ukulawula amplitude (ukushintshashintsha kwezwi) isignali, ngamanye amazwi, φ (t) = ω _{0 t} + _Δ φ ∙ sinΩt + φ ₀ = = φ _{0 +} lowo (t), lapho k - proportionality isici.

Isignali isigaba-modulated ngokuvamile esachazwa Inkulumo u (t) = U _n isono [ωt + φ (t)].

Lapho omunye ithoni ukushintshashintsha kwezwi [e (t) = E isono Ωt] esinalo: φ (t) = φ ₀ + KE isono Ωt = φ ₀ + Δφ _max isono Ωt.

Ngemva abambele amagugu φ (t) kule ndaba isignali isigaba-modulated sithola u (t) = U _n isono (ω _n t + φ ₀ + Δφ _max isono Ωt), lapho Δφ _max - ushintsho esiphezulu esigabeni wakhona amplitude we voltage control. Δφ _max ngenye ngokuthi engela ukushintshashintsha kwezwi Inkomba futhi luchazwa ngegama m.

Njengoba singabona, lapho m FM = Δφ _max = KE. Inani leso sikhathi of isikhathi-obuhlukahlukene isigaba engela Θ (t) uyalingana Θ (t) = ω _n t + φ ₀ + msin Ωt, ukuze ω = d Θ (t) / DT = ω _n + mΩ cosΩt, lapho mΩ = Δφ _max ω = Δ ω _n = kEΩ - esiphezulu imvamisa ukuphambuka ngoba FM ω _n, ngokuqondile wakhona amplitude futhi imvamisa we oscillation modulating.

Ngakho, lapho FM ukushintshashintsha kwezwi Inkomba esibonisa esiphezulu isigaba ushintsho wakhona isignali ukulawula amplitude futhi akuxhomekile imvamisa kwezwi. Ukwehlukahlukana imvamisa mayelana Incazelo (ukuphambuka) ngokuqondile wakhona amplitude kanye nokuvama voltage modulating.

Kuye ukushintshashintsha kwezwi isicelo esigabeni has izinhlobo eziningana. Omunye wabo, ikakhulukazi, kuyinto Ukwahlukaniswa Isigaba Shift Keying.

Kuleli fomu, kuncike isignali modulating kuyahlukahluka kuphela esigabeni isignali, nemvamisa amplitude ahlale njalo. Lapho inani Imininingwane RPM akuyona ngokuphelele isigaba ushintsho, futhi ukushintshashintsha yayo maqondana namagugu odlule.

wesifunda Electronic, elibangela ushintsho engela isigaba oscillation modulated (isihlobo esiphathiswa unmodulated) ngokuhambisana isignali modulating ibizwa ngokuthi modulator isigaba.

Sikhanyisiwe izinhlobo eziningi izithombe. Isikimu modulator elula yakhiwa varicap - diode uyakwazi ngaphansi umphumela ekushintsheni capacitance ukulawula voltage okuhlangana kuyo. Kulesi uhlelo, modulating voltage kushintsha umthamo we varicap. I shift isigaba incike ubukhulu eyisihlobo diode capacitance kanye R. umthwalo ukumelana

Ngakho, i-shift incike voltage ukushintshashintsha kwezwi. Lokhu kubangela ukushintshashintsha kwezwi isigaba isignali yomsakazo. Nokho, ukushintsha okunjalo Lihlobene nokubhekana ubuso nonlinear modulating voltage varicap capacitance lihlobene nonlinear modulating voltage ukuthi kudala izinkinga ezengeziwe modulators zezakhiwo.

isigaba Pure ukushintshashintsha kwezwi uye ayitholakalanga isicelo ngokwanele ububanzi ngenxa kusimo akhona nomphela sina - ongaphakeme umsindo amasosha omzimba.