1.CVC na DSP mbelata mkpọtụ mkpọtụ:
Mgbe ndị na-azụ ahịa zụtara ekweisi Bluetooth, ha ga-anụ mgbe niile ọrụ mbelata mkpọtụ CVC na DSP nke ndị ahịa nwere n'ịkwalite ekweisi. N'agbanyeghị ole ndị ọrụ nụworo nkọwa ndị ahụ, ọtụtụ ndị na-azụ ahịa ka na-aghọtaghị ọdịiche dị n'etiti abụọ ahụ. Ihe dị iche, maka nsogbu ọrụ nka dị otú ahụ, anyị na-abịa na sayensị nke abụọ n'okpuru ụkpụrụ ọrụ na ọdịiche.
DSP bụ obere aka maka nhazi akara ngosi dijitalụ. Ụkpụrụ ya na-arụ ọrụ: igwe okwu na-anakọta mkpọtụ gburugburu ebe obibi dị n'èzí, mgbe ahụ site na usoro mbelata mkpọtụ na-arụ ọrụ n'ime ntị ntị, ọ na-emepụtagharị iji mepụta ụda ụda ntụgharị nke nha ụda ụda, nke na-akagbu mkpọtụ ma si otú ahụ nwetakwuo ihe. Mmetụta mbelata mkpọtụ dị mma.
CVC dị mkpụmkpụ maka Nwepụta Voice Clear. Ọ bụ teknụzụ mbelata mkpọtụ mkpọtụ software. Ụkpụrụ bụ ikpochapụ ụdị mkpọtụ mkpọtụ dị iche iche site na ngwa nbibi mkpọtụ arụnyere na igwe okwu.
Ihe dị iche dị ka ndị a:
a. n'ihi na ihe dị iche iche, CVC technology bụ tumadi maka nkwughachi eme n'oge oku, DSP bụ tumadi n'ihi na elu na ala ugboro mkpọtụ na mpụga gburugburu ebe obibi.
b. dị iche iche na-erite uru, DSP technology tumadi na-eme ka headset ọrụ onwe ego, na CVC tumadi na-erite uru ndị ọzọ.
Na nchịkọta, ekweisi na-eji DSP na teknụzụ mbelata mkpọtụ mkpọtụ CVC nwere ike belata mkpọtụ nke gburugburu mpụga nke oku ahụ nke ọma, ma melite ogo oku na ụda nke ekweisi.
2.ANC mbelata mkpọtụ:
ANC na-ezo aka na njikwa mkpọtụ arụ ọrụ, nke na-ebelata mkpọtụ. Ụkpụrụ bụ isi bụ na usoro mbelata mkpọtụ na-emepụta ebili mmiri na-atụgharị na ụda nke dị n'èzí, na-ewepụ mkpọtụ ahụ. Onyonyo 1 bụ eserese schematic nke mkpọtụ mkpọtụ na-akagbu ekwe ntị. A na-etinye mgbawa ANC n'ime ekwe ntị. Ref mic (igwe okwu ntụaka) na-anakọta mkpọtụ gburugburu na ekwe ntị. Igwe okwu mperi (Error Igwe okwu) na-anakọta mkpọtụ fọdụrụnụ ka mbelata mkpọtụ na ekwe ntị. Ọkà okwu na-akpọ mgbochi mkpọtụ mgbe nhazi ANC.
Onyonyo 2 bụ eserese schematic nke sistemu ANC, nke nwere akwa atọ, nke nwere ahịrị ndị nwere akara kewapụrụ. Ụzọ kachasị elu bụ ọwa ụda si ref mic gaa na mic njehie, ọrụ nzaghachi bụ P(z) P(z) nọchiri anya ya; oyi akwa nke etiti bụ ọwa analọg, ebe ụzọ nke abụọ bụ ụzọ si na mmepụta nzacha na-agbanwe agbanwe gaa na nlọghachi azụ. Gụnyere DAC, nzacha nwughari, ihe nkwuputa ike, nkwughachi okwu okwu, nwetaghachi, ihe nrịbama mbụ, nzacha mgbochi, ADC; ala oyi akwa bụ dijitalụ ụzọ, ebe adaptive nzacha mgbe niile adjusts nyo arọ ọnụọgụ iji belata ihe fọdụrụ ruo mgbe convergence . Ihe ngwọta a na-ahụkarị bụ iji mejuputa ihe nzacha na-eji ihe nzacha FIR yana ngwakọta LMS algorithm. Mee ka eserese 2 dị mfe ma nweta foto 3.
Ka m kwuo nkenke maka ụkpụrụ nke nzacha ihe nzacha na LMS (Least mean square) algọridim, wee na-ese onyinyo 3. Dị ka egosiri na eserese 4, nyere ntinye xx na ihe a chọrọ dd, ihe nzacha na-agbanwe agbanwe na-emelite ọnụọgụgụ ọ bụla iteration nke mere na ọdịiche dị n'etiti mmepụta yy na dd na-adị ntakịrị ma na-adị ntakịrị ruo mgbe ihe fọdụrụ dị nso na efu ma jikọta. LMS bụ algọridim emelitere maka nzacha na-agbanwe agbanwe. Ebumnuche ebumnuche LMS bụ square nke njehie ozugbo e2(n)=(d(n)−y(n))2e2(n)=(d(n)−y(n))2, iji wedata. ọrụ ebumnobi, Itinye mgbada gradient na-enye usoro emelitere nke algọridim. (Echiche algọridim nke iji mgbada gradient belata ebumnobi wee nweta usoro emelitere nke paramita a ga-achọ bụ ihe a na-ahụkarị, dị ka nkwụghachi azụ linear.) Usoro mmelite nke LMS algọridim site na iji nzacha FIR bụ: w(n+1). ) = w(n)+μe(n)x(n)w(n+1)=w(n)+μe(n)x(n), ebe μμ bụ nzọụkwụ nha. Ọ bụrụ na ejiri ntugharị gbanwe nha μμ, ọ bụ usoro LMS nke nzọụkwụ site na nzọụkwụ.
Ka anyị kwuo banyere eserese 3. Ebe a na-emepụta ihe nzacha mgbanwe mgbe S (z) S (z) jiri tụnyere mmepụta ọchịchọ. S(z)S(z) ga-ebute enweghị ntụkwasị obi. N'ime akwụkwọ akụkọ, "n'ụzọ ziri ezi, mgbaama njehie ahụ emeghị nke ọma" Ka oge na-aga na akara ngosi", nchikota nke LMS agbajiwo. (Agaghị m achọpụta ihe ọ pụtara T__T) Ụzọ dị irè bụ FXLMS (Filtered-X LMS), nke na-enye ohere ka x (n) tinye na modul LMS site na Sˆ (z) S ^ (z), Sˆ ( z S^(z) bụ atụmatụ S(z)S(z) ebumnobi nke FXLMS:
E2(n)=(d(n)-s(n)∗[wT(n)x(n)])2,
E2(n)=(d(n)-s(n)∗[wT(n)x(n)])2,
Ya mere gradient=-2e(n)s(n)∗x(n) -2e(n)s(n)∗x(n), ebe s(n)s(n) amaghi, ya na ntule ya, ya mere. Usoro mmelite FXLMS bụ
w(n+1)=w(n)+μe(n)x'(n),
w(n+1)=w(n)+μe(n)x'(n),
Ebe x'(n)=sˆ(n)∗x(n)x'(n)=s^(n)∗x(n).
Mgbe nzacha ngbanwe na-agbakọta, E(z)=X(z)P(z) -X(z)W(z)S(z)≈0E(z)=X(z)P(z) -X(z) ) W(z) S(z) ≈ 0, ya mere W(z) ≈ P(z) / S(z) W(z) ≈ P(z) / S(z). Ya bụ, ọnụ ọgụgụ dị arọ nke nzacha ihe ngbanwe na-ekpebi site na ụzọ mbụ na ụzọ nke abụọ nke ekweisi. Ụzọ bụ isi na ụzọ nke abụọ nke ekweisi ekweisi kwụsiri ike, ya mere ọnụ ọgụgụ ịdị arọ nke nzacha ihe na-agbanwe agbanwe kwụsiri ike. Ya mere, n'ihi ịdị mfe, a na-ekpebi ọnụọgụ dị arọ nke ụfọdụ ekweisi ANC ndị na-emepụta ihe na ụlọ ọrụ mmepụta ihe. N'ezie, ahụmahụ na-ege ntị nke a ANC ntị ntị bụ doro anya na ọ dịghị mma dị ka ANC earphone na ezi mgbanwe pụtara, n'ihi na n'ezie ọnọdụ, mpụga mkpọtụ metụtara ntụziaka nke ntị ntị, dị iche iche okpomọkụ na ihe ndị yiri ya nwere ike inwe mmetụta na. nzaghachi ọwa nke ntị ntị.
Nnwale Matlab
Dee koodu Matlab, na-eji ihe nzacha na-agbanwe agbanwe nke nha nha nha LMS, a na-egosipụta nsonaazụ ịme anwansị na eserese 5. N'ime 0 ruo 2 kHz, a na-eji feedforward ANC kpochapụ mkpọtụ ọcha Gaussian, na ụda mkpọtụ bụ 30 dB + na nkezi. FXLMS dị n'ọbá akwụkwọ Matlab bụ nke a kapịrị ọnụ, mmetụta ya ka njọ.
Ajụjụ & Ajụjụ
a. Kedu ihe kpatara ANC ji bụrụ naanị maka mkpọtụ obere oge n'okpuru 2 kHz?
N'otu aka ahụ, mkpuchi ụda anụ ahụ nke ekweisi (mbelata mkpọtụ mkpọtụ) nwere ike igbochi mkpọtụ ụda ugboro ugboro nke ọma, ọ dịghịkwa mkpa iji ANC belata mkpọtụ ụda ugboro ugboro. N'aka nke ọzọ, ụda olu dị ala nwere ogologo ogologo ogologo ma nwee ike iguzogide oge ụfọdụ igbu oge, ebe ụda ụda dị elu na-enwe obere ebili mmiri ma na-enwe mmetụta maka ngbanwe nke oge, ya mere ANC na-ewepụ ụda ụda dị elu.
b. Mgbe oge elekere eletrọnịkị dị ukwuu karịa igbu oge mbụ, kedu ka enwere ike isi belata arụmọrụ nke algọridim?
P(z) igbu oge dị ntakịrị, S(z) igbu oge buru ibu, dị ka P(z)=z-1, S(z)=z-2, naanị mgbe W(z)=z nwere ike imezu ihe achọrọ, na-abụghị. -akpata, enweghị ike iru.
c. Kedu ihe dị iche n'etiti Feedforward ANC, ANC feedforward nke warara na nzaghachi ANC?
Ihe nhazi Feedforwad nwere ref mic yana mic njehie na-anakọta mkpọtụ mpụga yana akara mpụta dị n'ime, otu n'otu. Nhazi nzaghachi nwere naanị otu igwe mperi, yana akara nrụtụaka na-ebute site na mperi mperi yana nzacha nzacha.
Mgbasa mgbasa ozi Broad-band bụ usoro akọwara n'elu. N'ime usoro dị warara, ụda mkpọtụ na-emepụta ihe na-eme ka mgbama na-akpalite, na onye na-emepụta ihe na-emepụta akara ngosi maka nzacha mgbanwe. Ọdabara naanị maka iwepụ mkpọtụ oge.
Nzaghachi ANC na-eji igwe okwu mperi nwetaghachi mgbama anakọtara site na ref mic n'usoro ntinye n'ihi na ọ nwere naanị igwe mperi mperi. Ụzọ ahụ adịghị egbo mmachi kpatara ya, ya mere, ọ bụ naanị ihe ndị a na-ahụ maka mkpọtụ a na-atụ anya ya, ya bụ ụda oge nke narrowband, na-ekpochapụ. Ekwesiri iburu n'uche na ọ bụrụ na onye na-azụ ahịa adịghị egbo ihe mgbochi kpatara ya, ya bụ, oge elekere eletrọnịkị dị ogologo karịa ogologo oge ụda olu ọwa, ọ nwere ike iwepụ naanị ụda oge narrowband.
Enwekwara ihe owuwu ANC ngwakọ nke gụnyere ma ihe nrịbama na nhazi nzaghachi. Isi uru bụ na ị nwere ike ịchekwa usoro nke nzacha ngbanwe.
