Walkie -Talkie ginra hta 21.4MHz hka ja ai lam hpe jai lang ai

Walkie -Talkie ginra hta 21.4MHz hka ja ai lam hpe jai lang ai

21.4MHz filter hpe walkie-talkie hkap la ai ni hta, lapran na frequency (IF) filter hku nna lang chye ai rai nna, shi a bungli galaw ai lam gaw, walkie-talkie ni a madung masat kumla lahkawng hpe hkrak dawdan ya ai: lata la ai lam hte hkam sha lu ai lam.

Lahta na lam ni kaw nna sung sung sang lang dan na re.

1. Walkie-Talkie langai a "Lapran na Frequency" ngu ai gaw hpa rai ta?

Kaja ai bungli galaw lu na matu, walkie-talkies (kaga superheterodyne hkap la ai ni zawn) gaw hkap la ai radio nsen (RF) nsen ni hpe (ga shadawn, 400-470MHz) hkrak sha n-gun ja shangun nna, n-gun n-jahten kau ai. De a malai, shanhte gaw lawu na lahkam ni hpe hkan sa ma ai:1 Mixing: Hkap la ai nsen kaba ai RF signal hpe buga na oscillator kaw na pru wa ai signal hte kayau kaya galaw ai.2 Lapran na Frequency hpe shabyin ai: Kaja wa ngut ai hpang, n-gun n rawng ai signal nnan hpe shapraw ai, dai gaw n-gun n rawng ai signal rai nga ai.3 TheIFlt: Fimplified a grai dam lada ai hku filter galaw ai.

"Superheterodyne" hkrang masa a akyu gaw, ndai ngang grin ai IF daw hku nna, n-gun atsam hte lata la ai lam (htingbu htingbyen na channel ni a shingjawng ai lam hpe yeng seng kau lu ai atsam) law malawng hpe lu la ai majaw, circuit hkrang hpe ngang grin ai hte bungli galaw ai lam grai kaja hkra galaw lu ai.

2. Hpa majaw 21.4MHz rai ta?

21.4MHz gaw VHF/UHF band ni hta (walkie-talkies ni lang ai band ni lawm ai) grai htuk manu ai madang IF frequency langai rai nga ai. Shi a labau hte hpaji masa lam ni hta:

Kungkyang ai hpaga lam npawt nhpang: 21.4MHz frequency a matu, kungkyang ai, ngang grin ai, manu n law ai-filter, amplifier, hte dai hte seng ai arung arai ni law law nga ai.

Performance hte manu jahpu lapran hta rap ra ai lam: Ndai frequency gaw sumla hpe hkra machyi shangun ai (common reception interference) hpe hkrak hkra pat shingdang lu na daram n-gun ja ai; dai aten hta sha, n-gun n law ai majaw, -Q (quality factor) tsaw ai hka htung ni hpe (crystal hka htung hte ceramic hka htung zawn re ai) hkrang shapraw nna galaw shapraw na matu loi ai.

Labau hta sali wunli hkam la ai lam: Ndai frequency hpe matut mahkai lam hta shaning tsa lam hku lang wa sai rai nna, classic walkie-talkie chips hte hparan ladat law law hpe ndai lapran na frequency grup yin hta galaw da ai.

3. Walkie-Ga shaga ai jak ni hta 21.4MHz Filter a madung lit

21.4MHz IF daw hta, filter gaw tengman ai "chyinghka sin ai wa" rai nga ai. Shi a lit gaw ahkyak ai:1 Selectivity hpe grau kaja hkra galaw na

Function: Selectivity ngu ai gaw, hkam la ai wa ra sharawng ai signal hpe signal law law kaw na garan ginhka lu ai atsam hte makau grup yin na channel shingjawng ai signal ni hpe pat shingdang lu ai atsam hpe tsun mayu ai.

Gara hku galaw ai: 21.4MHz filter gaw grai n-gun ja ai frequency mahtai jaw ai curve nga ai (galaw madang gaw "brick bunghku" zawn re ai). Dai gaw 21.4MHz hpe ginjaw hku nna grai hkrak ai bandwidth hte signal daw langai hpe sha lai shangun ai (ga shadawn, walkie-talkies ni hta law law lang lang ai ±6.25kHz, ±7.5kHz, ±12.5kHz, channel gap hkat ai lam n bung ai hte maren).

Tatut galaw mai ai lam: Grai ni ai frequency ni nga ai radio station lahkawng gaw kalang ta shapoi ai shaloi, 21.4MHz filter kaba hte hpaw da ai walkie-talkie gaw, yaw shada ai radio station a nsen hpe asan sha na lu nna, kaga makau grup yin na crosstal channel a signal hpe avoid de hkrat sum shangun lu ai. Ndai filter n lawm yang (sh) n kaja ai hku galaw ai filter hte rai yang, "channel crosstalk" ngu ai nsen hpe na lu na re.

Hkamja lam hpe grau kaja hkra galaw u

Function: Sensitivity ngu ai gaw, hkam la ai wa a n-gun kya ai signal ni hpe hkam la lu ai atsam hpe tsun mayu ai.

Gara hku galaw ai: IF signal hpe n-gun n-jaw shi yang, -band nsen hte n-gun n-gun ni hpe - kaw na - hpe shawng n-gun n-jaw na matu filter hpe lang ai. Ndai hku nna, madung amplification gaw "san seng ai" akyu rawng ai signal hkum nan rai nga ai. Amplification hpe filter n galaw ai sha galaw yang, out-of-band nsen mung amplify byin mat nna, n-gun kya ai effective signal hpe hka kata de lup kau ya na re.

Tatut akyu: Na a walkie-talkie hpe tsan ai shara kaw (sh) n-gun kya ai signal ni hta pyi chye na loi ai hku matut mahkai lu hkra galaw ya ai.

4. 21.4MHz hka ja ai ladat amyu myu

Walkie-talkies ni hta, 21.4MHz filter ni hta madung hku nna lawu na amyu ni hpe lawm ai:

Ceramic hka ja ai jak:

Features: Manu n law ai, kaji ai, kam mai ai lam grai law ai, galai shai ra ai lam n nga ai.

Ladat ni: Mid- kaw nna-low-end walkie-talkies ni hta law law lang ai, shi a bungli galaw ai lam gaw, htunghking ra kadawn ai lam law malawng hpe hkap la lu na matu ram nga ai. Shi a bandwidth hte shape factor (filter jut a n-gun hpe shadawn na matu masat kumla langai) gaw, crystal filter ni hta loi mi n kaja ai raitim, LC filter ni hta grau kaja ai.

Hka htung hka ja ai:

Features: Grai tsaw ai Q value nga ai, dai majaw lata la ai lam gaw grai kaja ai, hkrang masa (shape factor) mung ideal state hte grai ni ai.

Application: Ga law malawng lang ai gaw, grai tsaw ai professional walkie-talkie ni hta (sh) grai tsaw ai anti-hkap la ai atsam ra ai aten ni hta lang ai. Dai manu gaw ceramic filter ni hta grau law ai.