21,4MHz Filɛtiri waleyali Walkie-Talkie foro kɔnɔ

21,4MHz Filɛtiri waleyali Walkie-Talkie foro kɔnɔ

A ka c’a la, 21,4MHz filɛri bɛ kɛ i n’a fɔ cɛmancɛ-fɛrɛnkan (IF) filɛri walkie-talkie jaabiw la, wa a baarakɛcogo bɛ walkie-talkies taamasiyɛn jɔnjɔn fila dantigɛ k’a ɲɛsin ɲɔgɔn ma: sugandili ni sɛgɛsɛgɛli.

An bɛna ɲɛfɔli kɛ ka ɲɛ ka bɔ nin fan ninnu na:

1. Walkie-Talkie ka "Fɛrɛnkan cɛmancɛ" ye mun ye?

Walasa ka baara kɛcogo ɲuman sɔrɔ, walkie-talkies (ani superheterodyne sɔrɔbaga wɛrɛw fana) tɛ arajolakalan (RF) taamasiɲɛw sɔrɔlenw bonya ani k’u demodulate (misali la, 400-470MHz). O nɔ na, u bɛ nin fɛɛrɛ ninnu ta:1 Mixing : RF signal min bɛ sɔrɔ ni frequency high-frequency ye, o bɛ ɲagami ni signal ye min bɛ bɔ sigida oscillateur fɛ.2 Frequence intermédiaire (Fɛrɛnkan cɛmancɛ) bɔli : ɲagaminen kɔfɛ, signal kura min bɛ ni frequency fixe ye, o bɛ bɔ, o ye frequency cɛmancɛ ye.3 IF Amplification and Filtering: IF signal fixe bɛ bonya kosɛbɛ ka filɛri kɛ ka gɛlɛn kosɛbɛ.

"Superheterodyne" jɔcogo nafa ye ko tɔnɔ ni sugandili fanba (se min bɛ se ka kanal kɛrɛfɛfɛnw fili) bɛ sɔrɔ nin IF dakun jɔlen in fɛ, o bɛ kɛ sababu ye ka ciriw dilanni sabati ani ka baara kɛcogo ɲuman kɛ.

2. Mun na 21,4MHz?

21.4MHz ye IF frequency standard ye min ka di kosɛbɛ VHF/UHF bandw kɔnɔ (walkie-talkies bɛ baara kɛ ni band minnu ye fana). A tariku ni fɛɛrɛko kunw ye :

Industri cakɛda kɔgɔlen : 21,4MHz frequency kama, filɛri kɔgɔlenw, sabatilenw, ani musaka dɔgɔmanw, amplificateurs ani a ɲɔgɔnnaw caman bɛ sɔrɔ.

Balan min bɛ baarakɛcogo ni musaka cɛ : O frequency (fɔkan) ka bon fo a bɛ se ka ja sɛgɛsɛgɛli bali ka ɲɛ (jaabi-dɛsɛ min bɛ kɛ tuma caman na); o waati kelen na, a ka dɔgɔ fo ka se ka filɛriw dilanni n’u dilanni nɔgɔya minnu ka bon-Q (jogoɲumanya hakɛ) filɛriw (i n’a fɔ kristalɛ filɛriw ani seramiki filɛriw).

Tariku ciyɛn : Nin fɔlikan in bɛ kɛ kunnafoniko siratigɛ la kabini san tan caman, wa klasiki walkie-talkie puwɛntiw ni furakɛlicogo caman dilannen don o cɛmancɛ fɔkan in lamini na.

3. 21,4MHz Filɛtiri jɔyɔrɔba Walkie-Talkies kɔnɔ

21,4MHz IF dakun na, filɛri ye "da kɔlɔsibaga" lakika ye. A jɔyɔrɔ ka bon kosɛbɛ:1 Ka Sugandili yiriwa

Baarakɛcogo: Sugandili bɛ tali Kɛ jatebɔla ka se ka taamaʃyɛn ɲininen Bɔ taamaʃyɛn caman na ani ka kanal danfaralanw Damatɛmɛ minnu bɛ kɛrɛfɛ.

A baara cogo : Filɛri 21,4MHz bɛ ni frequency response curve ye min ka gɛlɛn kosɛbɛ (a ka c’a la i n’a fɔ "brick wall"). A bɛ sira Di taamaʃyɛn yɔrɔ dɔ dɔrɔn ma min bɛ 21,4MHz Kɛ a cɛmancɛ ye ani a ka bandwidth tigitigiba ka Tɛmɛ (misali la, ±6,25kHz, ±7,5kHz, ±12,5kHz min bɛ Kɛ kosɛbɛ walkie-talkies (fɔlikanw) la, o bɛ Bɛn ni kanal danfara danfaralenw ye).

Nafa min bɛ sɔrɔ : Ni arajo fila minnu ka fɔkanw ka surun kosɛbɛ, olu bɛ ka cikanw ci ɲɔgɔn fɛ, walkie-talkie min bɛ ni 21,4MHz filɛri ye min bɛ baara kɛ kosɛbɛ, o bɛ se ka arajo laɲinilen mankan mɛn ka jɛya, k’a sɔrɔ a bɛ se ka arajoso laɲinilen mankan mɛn ka jɛya, k’a sɔrɔ a bɛ sira tɔ kelen min bɛ kɛrɛfɛ, o ka taamasiyɛnw damatɛmɛ cogo ɲuman na walasa ka a yɛrɛ tanga crosstalk ma. Ni nin filɛri in tɛ yen walima ni filɛri min tɛ baara kɛ ka ɲɛ, i bɛna "channel crosstalk" mankan mɛn.

2 Aw bɛ Sensitivite (hakilila) ɲɛ ka taa a fɛ

Baarakɛcogo: Sensitivity (sɛgɛsɛgɛli) bɛ tali kɛ a minɛbaga ka se ka taamasiyɛn barikamaw sɔrɔ.

A bɛ baara kɛ cogo min na: Sani ka IF taamasiyɛn bonya, filɛri bɛ kɛ ka -banda mankan ni fɛnw cɛtigɛ fɔlɔ. O cogo la, amplification (fɔlikan)ba ye taamaʃyɛn nafama "saniyalen" yɛrɛ ye. Ni fanga bonya kɛra k’a sɔrɔ filɛli ma kɛ, out-of-band mankan fana bɛna bonya, o la, taamasiyɛn nafama barikama bɛ jigin.

Nafa min bɛ sɔrɔ: A bɛ a to i ka walkie-talkie ka kumaɲɔgɔnya faamuyalen mara hali ni yɔrɔ janw ye walima ni taamasiyɛnw barika ka dɔgɔ.

4. 21,4MHz Filɛtiri suguyaw

Walkie-talkies kɔnɔ, 21,4MHz filɛri minnu bɛ kɛ tuma caman na, olu bɛ nin suguya ninnu de la kosɛbɛ:

Filtre céramique: 1 .

Fɛn minnu bɛ a kɔnɔ: A musaka ka dɔgɔ, a bonya ka dɔgɔ, a bɛ se ka da a kan kosɛbɛ, wa a man kan ka ladilan.

Baarakɛcogo: A bɛ kɛ kosɛbɛ cɛmancɛ-ka se-low{2}}ban-bankisɛ-fɔlikanw na, wa a baarakɛcogo bɛ se ka mago kɔrɔ fanba ɲɛ. A ka bandwidth ani shape factor (min ye taamasiyɛn ye min bɛ filɛri dawolo janya suman) ka teli ka juguya dɔɔnin ka tɛmɛ kristalɛ filɛriw kan nka a ka fisa kosɛbɛ ni LC filɛriw ye.

Filɛri min bɛ kɛ ni Kristali ye:

Fɛn minnu bɛ a la: Q hakɛ ka bon kosɛbɛ, o la sugandili ka ɲi kosɛbɛ, wa a cogoya hakɛ bɛ surunya kosɛbɛ cogoya ɲuman na.

Baarakɛcogo: A ka c’a la, a bɛ kɛ baarakɛlaw ka walkie-kanw na minnu ka bon kosɛbɛ walima waati minnu bɛ se ka kɛ sababu ye ka fɛnw kɛlɛli seko camanba de wajibiya. O musaka ka bon ni seramiki filɛriw ta ye.