Imibuzo Eyisibonelo Ngengxoxo Yamaza Omsakazo
Amagagasi omsakazo awuhlobo lwemisebe kagesi esebenza ekuxhumaneni okungenantambo. Ngamaza asukela kuma-kilohertz ambalwa (kHz) kuya kuma-gigahertz amaningana (GHz), amagagasi omsakazo asetshenziswa ezinhlotsheni eziningi zokusebenza—kusukela ekusakazweni komsakazo kanye nethelevishini kuya ezinhlelweni zokuxhumana zeselula. Kulesi sihloko, sizoxoxa ngezibonelo zamagagasi omsakazo kanye nezincazelo zawo ukuze kusisize siqonde izimiso kanye nokusetshenziswa kwala magagasi empilweni yansuku zonke.
Isibonelo Umbuzo 1: Imvamisa kanye nobude be-Wave
Umbuzo:
Isiteshi somsakazo sidlulisa amaza omsakazo ngesivinini esingu-100 MHz. Bala ubude be-wavelength. (Ijubane lokukhanya lingu-3 x 10^8 m/s.)
Ingxoxo:
Imvamisa (f) kanye nobude besikhathi (λ) bamagagasi kagesi kuhlobene nesivinini sokukhanya (c) ngesibalo:
\[ c = f \izikhathi \lambda \]
Kuphi:
– \( c \) = isivinini sokukhanya (3 x 10^8 m/s)
– \( f \) = imvamisa (100 MHz noma 100 x 10^6 Hz)
– \( \lambda \) = ubude besikhathi (obuzotholakala)
Kusukela ku-equation engenhla, ubude be-wavelength bungabalwa kanje:
\[ \lambda = \frac{c}{f} \]
Ngakho-ke:
\[ \lambda = \frac{3 \times 10^8}{100 \times 10^6} = 3 \ \text{meter} \]
Ngakho-ke, ubude be-wavelength yemvamisa engu-100 MHz bungama-3 amamitha.
Isibonelo Umbuzo 2: Amandla Okudlulisa Nokuqina
Umbuzo:
Isithumeli somsakazo esingu-50-watt sikhipha amaza omsakazo ngendlela e-isotropically (ngokufanayo kuzo zonke izinhlangothi). Bala ubukhali bamaza omsakazo ebangeni elingamamitha ayi-10 ukusuka kusithumeli.
Ingxoxo:
Ubukhulu (I) begagasi elikhishwa yi-isotropically bungabalwa ngokuthi:
\[ I = \frac{P}{A} \]
Kuphi:
– \( P \) = amandla okudlulisa (ama-watts angu-50)
– \( A \) = indawo engaphezulu yembulunga (4πr^2)
Ebangeni (r) = amamitha ayi-10, indawo engaphezulu yebhola yile:
\[ A = 4\pi (10)^2 = 400\pi \]
Ngakho-ke:
\[ I = \frac{50}{400\pi} = \frac{1}{8\pi} \ \text{watt/m}^2 \]
Ngakho-ke, amandla amagagasi omsakazo ebangeni elingamamitha ayi-10 ukusuka ku-transmitter angama-watt/m².
Isibonelo Umbuzo 3: Ububanzi Bomkhawulo kanye Nomthamo Wesiteshi
Umbuzo:
Isiteshi sokuxhumana sinomkhawulokudonsa ongu-20 MHz. Uma usebenzisa i-QPSK (Quadrature Phase Shift Keying) modulation, yimuphi umthamo omkhulu wesiteshi?
Ingxoxo:
Ukuguqulwa kwe-QPSK kunezigaba ezine ezahlukene, ngakho-ke kungadlulisela ama-bits ama-2 ngophawu ngalunye ngesikhathi esisodwa.
Inani lezimpawu ngomzuzwana ezingaphathwa yi-bandwidth ye-20 MHz yile:
\[ \umbhalo{Uphawu} = 20 \izikhathi eziyi-10^6 \ \umbhalo{uphawu/isekhondi} \]
Njengoba i-QPSK ithumela ama-bits ama-2 ngesimboli ngasinye, umthamo noma inani lama-bits ngomzuzwana (i-bitrate) yilokhu:
\[ \umbhalo{Bitrate} = 20 \uphindwe izikhathi ezingu-10^6 \uphindwe izikhathi ezingu-2 = 40 \\umbhalo{Mbps} \]
Ngakho-ke, amandla aphezulu esiteshi angama-40 Mbps.
Isibonelo Umbuzo 4: Ukuphazamiseka Nokuphazamiseka
Umbuzo:
Umsakazi osebenzisa imvamisa engu-101.1 MHz uhlangabezana nokuphazamiseka komunye umsakazi osebenzisa imvamisa engu-101.3 MHz. Bala imvamisa yokushaya ephumayo.
Ingxoxo:
Imvamisa yokushaya \( f_{beat} \) yenzeka ngenxa yomehluko phakathi kwemvamisa emibili eseduze futhi ingabalwa ngokuthi:
\[ f_{beat} = |f_1 – f_2| \]
Kuphi:
– \( f_1 \) = 101.1 MHz
– \( f_2 \) = 101.3 MHz
Ngakho-ke:
\[ f_{beat} = |101.1 – 101.3| = | -0.2 | = 0.2 \ \umbhalo{MHz} \]
Ngakho-ke, imvamisa yokushaya ephumelayo ingu-0.2 MHz.
Isibonelo Umbuzo 5: Umphumela we-Doppler kuma-Radio Waves
Umbuzo:
Isiteshi somsakazo sidlulisa umsindo ngesivinini esingu-95 MHz. Indiza isondela esiteshini somsakazo ngesivinini esingu-340 m/s. Bala imvamisa etholwa yindiza uma isivinini samagagasi omsakazo silingana nesivinini sokukhanya (3 x 10^8 m/s).
Ingxoxo:
Umphumela we-Doppler wamagagasi omsakazo ungachazwa kanje:
\[ f_{accept} = f_{0} \left(\frac{c + v}{c}\right) \]
Kuphi:
– \( f_0 \) = imvamisa yokuqala (95 MHz)
– \( v \) = isivinini sendiza (340 m/s)
– \( c \) = isivinini segagasi (3 x 10^8 m/s)
Ngakho-ke:
\[ f_{accept} = 95 \times 10^6 \left(\frac{3 \times 10^8 + 340}{3 \times 10^8}\right) \]
\[ f_{accept} = 95 \times 10^6 \left(\frac{3 \times 10^8 + 3.4 \times 10^2}{3 \times 10^8}\right) \]
\[ f_{accept} \cishe 95 \times 10^6 \left(1 + \frac{3.4 \times 10^2}{3 \times 10^8}\right) \]
\[ f_{accept} \cishe kube ngu-95 \izikhathi ezingu-10^6 \kwesobunxele(1 + 1.1333 \izikhathi ezingu-10^{-6}\kwesokudla) \]
\[ f_{accept} \cishe kube ngu-95 \izikhathi ezingu-10^6 \izikhathi ezingu-1.0000011333 \]
\[ f_{accept} \cishe 95.000107 \ \text{MHz} \]
Ngakho-ke, imvamisa etholwa yindiza esondelayo icishe ibe ngu-95.000107 MHz.
I-Penutup
Ukuqonda izimiso eziyisisekelo kanye namaphethini ekhompyutha amaza omsakazo kubalulekile emikhakheni ehlukahlukene yobunjiniyela kanye nesayensi. Izinkinga ezingenhla zinikeza izibonelo ezithile zendlela i-physics yamaza omsakazo engasetshenziswa ngayo ezimweni ezahlukene ezisebenzayo. Indlela eya ekuqondeni okujulile iwukuzijwayeza okuqhubekayo kanye nokuhlola ukusetshenziswa kwamaza omsakazo emhlabeni wangempela kubuchwepheshe bokuxhumana esibusebenzisa nsuku zonke.
