Ngā Tikanga Hanga Reo Irirangi AM me ngā Wāhanga Māmā
Ko te reo irirangi AM (Amplitude Modulation) tētahi o ngā hangarau whakawhitiwhiti kōrero tino rongonui, tino whakamīharo hoki hei ako. Ahakoa he tokomaha te hunga e mōhio ana ki te reo irirangi FM, ki te rere mamati rānei, he tino mātauranga tonu te reo irirangi AM nā te mea he māmā noa iho, he ngāwari hoki ki te mārama ki ngā ara iahiko. Mā te whakamahi i ētahi wāhanga taketake, ka taea e koe te hanga i tētahi kaiwhiwhi reo irirangi AM ngāwari ka taea te whiwhi teihana ā-rohe—i ngā wāhi he kaha te tohu. Ka matapakihia e tēnei tuhinga te hanga i tētahi reo irirangi AM mā te whakamahi i ngā wāhanga ngāwari, ōna mātāpono mahi, me ngā mahi huihui.
1. Te Mātāpono Mahi Poto o te Reo Irirangi AM
Ko te mahi a te reo irirangi AM mā te hopu i ngā ngaru reo irirangi e "rerekē" ana te kaha i runga i te āhua o te tohu oro (oro). E toru ngā mahi matua a te kaiwhiwhi reo irirangi AM noa:
1. Hopukia ngā tohu reo irirangi mā te pūihi me te ara iahiko whakaōrite.
2. Te wehewehe (te tango i ngā whakarerekētanga) o te tohu oro mai i te ngaru kawe RF mā te whakamahi i tētahi pūoko (he diode te nuinga).
3. Tahurihia ngā tohu oro hei oro mā roto i ngā taringaoro, i ngā whakakaha oro me ngā kaikorero.
Ko te reo irirangi AM māmā rawa atu e mōhiotia ana ko te reo irirangi tioata, ka taea e ia te mahi ahakoa kāore he pākahiko mena he kaha te tohu. Heoi, kia pai ake ai ngā hua, ka taea e tātou te tāpiri i tētahi whakakaha oro māmā.
2. Ngā Wāhanga Māmā e Hiahiatia ana
Ko ngā wāhanga e whai ake nei e whakamahia whānuitia ana mō tētahi kaiwhiwhi reo irirangi AM māmā:
– He waea enamel (waea aukume) hei hanga koiri, hei tauira, he whānui 0,2–0,5 mm.
– He tokotoko ferite (he kōwhiringa engari he tino āwhina) hei matua koiri hei whakanui ake i te aro.
– Pūnga iahiko rerekē (tata ki te 10–365 pF) hei whakatikatika auau. Ka taea hoki e koe te whakamahi i te pūnga iahiko varco mai i tētahi reo irirangi tawhito.
– Te taiohiko kimi: He pai te 1N34A (germanium), engari ka taea hoki e koe te whakamahi i te 1N60, i te Schottky rānei pērā i te BAT41 (he pai ake i ngā taiohiko silicon noa).
– He pūnga iti (hei tauira, 10 nF–100 nF) mō te tātari/wehewehe oro (whiringa).
– Ngā taringaoro ātete-teitei, ngā taringaoro piezo rānei. He iti te ātete-teitei o ngā taringaoro waea pūkoro o ēnei rā, ā, kāore e pai ana mēnā kāore he whakakaha oro.
– Pūihi: taura 5–20 mita te roa (ka roa ake, ka pai ake).
– Whenua: hononga ki te paipa wai/whenua hiko (haumaru) ki te whenua haukū rānei mā te tokotoko whakarewa.
– He papa parāoa, he papa kōhao rānei (perfboard), he rino whakapiri, me ngā taura hono.
Ki te hiahia koe kia pai ake te whakarongo:
– He IC whakakaha oro (hei tauira, LM386), he kaikorero iti 8 ohm, me te pākahiko 9V.
3. Ariā Porowhita: Kaiwhakatakoto LC me te Kaitirotiro Diode
Ko te wāhanga matua o te reo irirangi AM ko te ara iahiko whakahāngai LC (te inductor L me te capacitor C). Ka tīpakohia e tēnei ara iahiko tētahi auau kotahi mai i ngā tohu maha e whiwhihia ana e te pūihi. Ko te auau orooro tata ki:
\[
f = \frac{1}{2\pi\sqrt{LC}}
\]
Mā te whakamahi i tētahi pūnga iahiko taurangi, ka taea te whakarerekē i te uara o te C kia taea ai e te reo irirangi te "horoi" i ngā auau AM (tata ki te 530–1600 kHz, i runga i ngā paerewa ā-rohe).
I muri i te tīpakonga o te tohu e te ara iahiko LC, ko te diode te kawenga mō te kimi/te kimi i te kōpaki: ka whakatikahia te wāhanga ngaru RF kia puta ai he tohu oro.
4. Ngā Hipanga mō te Hanga i tētahi Reo Irirangi AM Māmā (Reo Irirangi Karaihe)
A. Te Hanga i tētahi Koiri
E rua ngā huarahi whānui:
1) Kopikopiko me te tokotoko ferrite
– Whakaritea he tokotoko ferrite (hei tauira, 8–12 cm te roa).
– Tākaihia te waea enamel kia 60–100 hurihanga, i runga i te varco me te whitiki ūnga.
– Me "pātene" mēnā e tika ana (hei tauira, i te takai 10, 20 rānei) mō te hononga pūihi kia pumau ake ai te whakahāngai.
2) Pōkai hau (uho hau)
– Whakamahia he paipa PVC he 2–3 henimita te whānui hei hanga.
– Hurihia te waea kia 80–120 takahuri.
– He nui ake ngā koiri hau engari ka pai te mahi, inā koa mēnā he rawaka te pūihi.
Kia mōhio: Kāore e tika kia tino tika te maha o ngā hurihanga. Ka taea e koe te whakamātau: ki te raru koe ki te whiwhi tohu, ngana ki te tāpiri, ki te whakaiti rānei i te maha o ngā hurihanga.
B. Te Huihui i te LC Tuner
– Honoa te koiri L kia whakarara ki te pūnga iahiko rerekē C.
– Ka honoa tetahi pito o te LC ki te pūihi (he maha ngā wā mā te tap), ko tetahi ki te whenua.
Ka pāngia te mahi e ngā tikanga hononga pūihi. I roto i te maha o ngā hoahoa, kāore te pūihi e hono tika ana ki te pito o te koiri matua, engari ki tētahi pato i waenga i ētahi hurihanga hei whakaiti i te kawenga me te whakapai ake i te whiriwhiri.
C. Te Tāpiri i ngā Diode Pūoko me ngā Utaina Ororongo
– Tangohia te tohu mai i te pūwāhi putanga o te ara iahiko LC (ko te pito "wera" o te koiri te tikanga).
– Whakauruhia ki roto i te diode germanium (te anode ki te LC, te cathode ki te taha oro).
– Whai muri i te diode, honoa ki tētahi taringaoro ātete teitei.
– Tāpirihia he pūnga whakarara 10 nF–100 nF ki te taringaoro (kāore he kōwhiringa) hei whakangawari i te toenga RF kia ma ake ai te oro.
Ko te kaupapa ariā māmā:
1. Pūihi → (kōiri tap) → Tāke LC
2. Tāke LC → taioata → taringaoro → whenua
D. Te Hononga i te Pūihi me te Whenua
He tino whakawhirinaki ngā reo irirangi kore mahi pēnei ki te pūihi me te whenua:
– Whakamahia te taura pūihi roa rawa atu, me whakanoho ki te wāhi teitei, kia matara atu i ngā pūtake haruru.
– He tino āwhina te whenua; he pai ake te hono atu ki te whenua haukū i te whenua "mānu".
– Āta karohia ngā wāhi e tata ana ki ngā rihi whakawhiti, ngā rama LED iti te utu, ngā pouara, ngā pona rānei, nā te mea ka taea e rātou te haruru/te haruru.
E. Whakatūnga
– Hurihia mārire te pūnga iahiko taurangi hei rapu i ngā teihana.
– I ētahi wā me neke te tūranga o te koiri i runga i te tokotoko ferrite hei huri i te hononga me te tiki i te tohu mōrahi.
5. Ngā Tohutohu hei Whakapai ake i te Tairongo me te Kounga o te Oro
1. Whakamahia te diode tika
He iti te ngaohiko whakamua o ngā taiohiko germanium (1N34A/1N60), ā, he pai mō ngā tohu ngoikore. Ka taea e ngā taiohiko silicon noa pērā i te 1N4148 te mahi, engari he iti ake te putanga i te nuinga o te wā.
2. Whakamahia ngā taringa piezo, ngā taringa ārai teitei rānei
Ka taea e ngā taringa taringa iti-ārai te whakakī i te ara iahiko pūoko, ā, ka uaua te rangona o te oro. Mēnā rānei, whakamahia he whakawhiti oro iti, tāpirihia rānei he whakakaha oro.
3. Tāpirihia he whakakaha LM386 (whiringa kore)
Ki te hiahia koe ki te whakamahi i ngā kaikorero, hangaia he atamira whakakaha:
– Ka haere te putanga i muri i te diode ki te tāuru LM386 (mā te pūnga honohono).
– Kei te LM386 he pākahiko 6–9V.
– Putanga ki ngā kaikōrero 8 ohm.
Ka tino whakanuia te rōrahi e tēnei.
4. Whakapaipai i te tahora
Ka taea e ngā taura roa rawa te hopu haruru. I ngā auau reo irirangi, he mea nui te whakatakotoranga. Kia poto rawa ngā hononga LC.
5. Kia aro ki te whiriwhiri
Ki te taupatupatu ngā teihana, ngana ki te whakarerekē i te huarahi e hono ai koe i te pūihi (whakaitihia te hurihanga o te pato), whakamahia rānei he koiri me te ferrite hei whakapai ake i te whiriwhiri.
6. Ngā Tuhipoka Haumaru me ngā Tuhipoka Whaihua
He haumaru ngā reo irirangi māmā noa iho nā te mea kāore e whakamahia he hiko teitei. Heoi anō:
– Ki te hono koe i tētahi whenua ki tētahi tāutanga whare, kia mārama koe ki te haumaru hiko. Kaua e hono atu ki tētahi ara iahiko morearea.
– Kei te mōrearea ngā pūihi o waho ki te pāngia e te uira. I te wā kino o te rangi, tangohia te pūihi mai i te ara iahiko.
– Ki te tāuta he pūihi roa ki waho, whakamahia ngā mea whakawehe me tētahi pūwāhi tomo haumaru.
7. Whakamutunga
He kaupapa hiko tino whai hua te hanga i tētahi reo irirangi AM me ngā wāhanga māmā hei mārama ki ngā ariā o te haruru, te kōwhiringa auau, me te tango tohu. Mā te whakamahi i tētahi koiri, i tētahi pūnga taurangi, i tētahi taio, i tētahi pūihi, me ngā taringaoro, ka taea e koe te hanga i tētahi kaiwhiwhi AM taketake e kaha ana ki te whiwhi i ngā pāhotanga ā-rohe. Kāore pea te hua e rite te kaha ki tētahi reo irirangi i hangaia i te wheketere, engari koinei te wāhi e takoto ai te uara ako: ka taea e koe te whakamātautau i te maha o ngā koiri, te momo taio, te roa o te pūihi, tae noa ki te tāpiri i tētahi whakakaha oro.
Ki te hiahia koe, ka taea hoki e au:
– Waihangahia he mahere ara iahiko katoa (reo irirangi karaihe, putanga LM386 rānei),
– Tātaihia te maha o ngā hurihanga e ai ki te varco kei a koe,
– Hoatu he tūtohutanga mō ngā wāhanga e ngāwari ana te kimi i ngā toa/mākete o te rohe.
