ʻO TDR kahi acronym no ka Reflectometry domain-time. He ʻenehana ana mamao ia e kālailai ana i nā nalu i hōʻike ʻia a aʻo i ke kūlana o ka mea i ana ʻia ma ke kūlana mana mamao. Eia kekahi, aia ka reflectometry domain manawa; Time-delay relay; Hoʻohana nui ʻia ka Transmit Data Register i ka ʻoihana kamaʻilio i ka wā mua e ʻike i ke kūlana haki o ke kaula kamaʻilio, no laila ua kapa ʻia ʻo ia he "cable detector". ʻO ka reflectometer domain manawa he mea uila e hoʻohana ana i ka reflectometer domain manawa e wehewehe a loaʻa nā hewa i nā kaula metala (no ka laʻana, nā kaula twisted pair a i ʻole coaxial). Hiki ke hoʻohana ʻia e ʻimi i nā discontinuities i nā mea hoʻohui, nā papa kaapuni i paʻi ʻia, a i ʻole kekahi ala uila ʻē aʻe.
Hiki i ka ʻaoʻao mea hoʻohana E5071c-tdr ke hana i ka palapala ʻāina maka hoʻohālike me ka ʻole o ka hoʻohana ʻana i ka mea hana code hou aʻe; Inā makemake ʻoe i ka palapala ʻāina maka manawa maoli, e hoʻohui i ka mea hana hōʻailona e hoʻopau i ke ana ʻana! Loaʻa i ka E5071C kēia hana
ʻIke holoʻokoʻa o ke kumumanaʻo hoʻoili hōʻailona
I nā makahiki i hala iho nei, me ka hoʻomaikaʻi wikiwiki ʻana o ka wikiwiki o nā kūlana kamaʻilio kikohoʻe, no ka laʻana, ʻo ka wikiwiki maʻalahi o ka mea kūʻai aku ʻo USB 3.1 bit rate i hiki i ka 10Gbps; Loaʻa iā USB4 ka 40Gbps; ʻO ka hoʻomaikaʻi ʻana o ka wikiwiki bit e hoʻomaka ai e ʻike ʻia nā pilikia i ʻike ʻole ʻia ma ka ʻōnaehana kikohoʻe kuʻuna. Hiki i nā pilikia e like me ka noʻonoʻo ʻana a me ka nalowale ke hana i ka hoʻopilikia ʻana o ka hōʻailona kikohoʻe, e hopena ana i nā hewa bit; Eia kekahi, ma muli o ka emi ʻana o ka palena manawa i ʻae ʻia e hōʻoia i ka hana pololei o ka hāmeʻa, lilo ka ʻokoʻa manawa i ke ala hōʻailona i mea nui loa. ʻO ka nalu electromagnetic radiation a me ka hoʻopili ʻana i hana ʻia e ka capacitance stray e alakaʻi i ka crosstalk a hana hewa i ka hāmeʻa. Ke liʻiliʻi a paʻa nā kaapuni, lilo kēia i pilikia nui; I mea e ʻoi aku ai ka ʻino, ʻo ka emi ʻana o ka volta lako e hopena i ka ratio signal-to-noise haʻahaʻa, e ʻoi aku ka maʻalahi o ka hāmeʻa i ka walaʻau;
ʻO ke kuhikuhi kū pololei o TDR ka impedance
Hoʻopili ʻo TDR i kahi nalu ʻanuʻu mai ke awa a i ke kaapuni, akā no ke aha ʻaʻole ka ʻāpana kū pololei o TDR i ka voltage akā impedance? Inā he impedance ia, no ke aha ʻoe e ʻike ai i ka lihi e piʻi ana? He aha nā ana i hana ʻia e TDR ma muli o ka Vector Network Analyzer (VNA)?
He mea hana ʻo VNA no ke ana ʻana i ka pane alapine (frequency) o ka ʻāpana i ana ʻia (DUT). I ke ana ʻana, hoʻokomo ʻia kahi hōʻailona hoʻonāukiuki sinusoidal i ka mea i ana ʻia, a laila loaʻa nā hopena ana ma ka helu ʻana i ka lakio amplitude vector ma waena o ka hōʻailona hoʻokomo a me ka hōʻailona hoʻoili (S21) a i ʻole ka hōʻailona i hōʻike ʻia (S11). Hiki ke loaʻa nā ʻano pane alapine o ka mea ma ke scan ʻana i ka hōʻailona hoʻokomo ma ka laulā alapine i ana ʻia. ʻO ka hoʻohana ʻana i ka kānana band pass i ka mea hoʻokipa ana hiki ke wehe i ka walaʻau a me ka hōʻailona makemake ʻole mai ka hopena ana a hoʻomaikaʻi i ka pololei o ke ana ʻana.
Kiʻikuhi kiʻikuhi o ka hōʻailona hoʻokomo, ka hōʻailona i hōʻike ʻia a me ka hōʻailona hoʻoili
Ma hope o ka nānā ʻana i ka ʻikepili, ua ʻike ʻia ʻo IT ua hoʻomaʻamaʻa ka mea hana a TDR i ka amplitude voltage o ka nalu i hōʻike ʻia, a laila hoʻohālikelike iā ia me ka impedance. Ua like ka coefficient reflection ρ me ka voltage i hōʻike ʻia i puʻunaue ʻia e ka voltage input; Hana ʻia ka reflection kahi i discontinuous ai ka impedance, a ua like ka voltage i hōʻike ʻia i hope me ka ʻokoʻa ma waena o nā impedances, a ua like ka voltage input me ka huina o nā impedances. No laila, loaʻa iā mākou ke ʻano hana penei. ʻOiai ʻo ka puka hoʻopuka o ka mea hana TDR he 50 ohms, Z0=50 ohms, no laila hiki ke helu ʻia ʻo Z, ʻo ia hoʻi, ke kiʻikuhi impedance o TDR i loaʻa ma ka pakuhi.
No laila, ma ke kiʻi ma luna, ʻoi aku ka liʻiliʻi o ka impedance i ʻike ʻia ma ke kahua mua o ka hōʻailona ma mua o 50 ohms, a paʻa ka pali ma ka lihi piʻi, e hōʻike ana ua kūlike ka impedance i ʻike ʻia me ka mamao i hele ʻia i ka wā o ka hoʻolaha ʻana o ka hōʻailona. I loko o kēia wā, ʻaʻole loli ka impedance. Manaʻo wau he ʻano pōʻai ke ʻōlelo ʻana ua manaʻo ʻia ua omo ʻia ka lihi piʻi ma hope o ka hōʻemi ʻana o ka impedance, a ua lohi hope. Ma ke ala ma hope o ka impedance haʻahaʻa, hoʻomaka ia e hōʻike i nā ʻano o kahi lihi piʻi a hoʻomau i ka piʻi ʻana. A laila hele ka impedance ma luna o 50 ohms, no laila ua ʻoi iki ka hōʻailona, a laila hoʻi mālie, a paʻa hope ma 50 ohms, a ua hiki ka hōʻailona i ke awa ʻē aʻe. Ma keʻano laulā, hiki ke manaʻo ʻia ka ʻāina kahi e hāʻule ai ka impedance he ukana capacitive ma ka honua. Hiki ke manaʻo ʻia ka ʻāina kahi e piʻi koke ai ka impedance he inductor ma ke ʻano series.
Ka manawa hoʻouna: Aug-16-2022
