Kwanan nan, duniyoyi biyu mabanbanta sun taru a cikin dakin gwaje-gwajenmu: duniyar masu watsa rediyo mai tsada da kuma tsarin rikodin siginar rediyo mai tsada.
Da farko, abokanmu nagari sun zo kusa da mu don yin software don yin rikodin sigina tare da band 500 MHz. Mu, ba shakka, ba za mu iya ƙi ba. Bayan haka, ya zama dole don yin wannan a kan jirgi daga kamfanin "Instrumental Systems", wanda na sani na dogon lokaci. A farkon aikin injiniya na, dole ne in yi aiki da kayan aikinsu da software.
Sai ga abokina ya zo daga kuma ya nemi yin tsarin sakawa don jirage marasa matuki ba tare da GPS ba. Ya zama dole, in ji shi, a kaddamar da wasan kwaikwayon a cikin gida. Kuma a kan titi kwanakin nan, ba kwa son ƙaddamar da dala miliyan da yawa a cikin sararin sama akan GPS mara aminci. Tsangwamar kewayawa ta zauna da zube .
Don sanyawa ba tare da tauraron dan adam tare da daidaito mafi kyau fiye da santimita goma a cikin yanki mai tsayi har zuwa kilomita guda, ban sami wani abu ba face fasahar UWB. DecaWave ya kasance a kasuwa na dogon lokaci, yana samar da guntu na DW1000 da kayayyaki dangane da shi. Guntu mai jujjuyawar UWB ne na ma'aunin IEEE 802.15.4-2011. A hanyar, abu ne na musamman, tare da sau biyu ko ma sau uku. Ina fatan za mu iya zurfafa zurfafansa a cikin ƴan shekaru masu zuwa mu rubuta game da shi. Tabbas ba za ku iya yi ba da wuri.
Amma a yau ba muna magana ne game da matsayi ba; za mu yi magana game da wannan a cikin jerin na gaba.
A yau muna rikodin siginar DW1000. Kuma bandwidth na wannan siginar ba ƙari ko ƙasa ba, amma 1000 ko 500 MHz, wanda lambar tashar ta ƙayyade. "Gaba ɗaya ta hanyar bazata" akwai kwamfuta tare da allon kewayawa akan tebur na gaba daga "Instrumental Systems" tare da FMC mezzanine daga Analog Devices.
Ya kamata a lura a nan "ga mai gabatar da kara" cewa AD9208 ADC fasaha ce ta takunkumi a yau. Ba za ku iya siyan shi bisa doka ba a Rasha, kodayake wani lokacin kuna son gaske. Amma an siyi wannan ƙayyadaddun tsarin lokaci mai tsawo da ya wuce, lokacin da babu takunkumi tukuna. Shi mai tsarki ne, kamar ran jariri. Ina fatan za a shigar da wannan ikirari a kan karar kuma za a ba da shi ga wanda ake tuhuma.
Yanzu ba za mu shiga cikin cikakkun bayanai na haɓaka software don yin rikodin rafi na samfuran cikin ƙwaƙwalwar kwamfuta ba. Abin takaici, har yanzu ba za mu iya buga lambar tushe na aikace-aikacen Linux ba tukuna. Amma muna fatan samun izini na wannan lokaci na gaba. Yana da kyau a lura cewa wannan bai kasance mai sauƙi ba, har ma da la'akari da abubuwan haɓaka software da aka bayar na Tsarin Kayan Aiki. ADC da kanta da tsarin clocking da fitarwa samfurori ta amfani da fasahar JESD204B suna da wahalar fahimta, kuma ana buƙatar faci na hardware a cikin tsarin daga AD. Siginar REFCLK yana da matukar mahimmanci don tsarin shigarwa, amma akan tsarin yana zuwa kafafun da ba daidai ba na mai haɗin FMC kuma, saboda haka, baya zuwa kafafun dama na FPGA. Dole ne in yi amfani da faci, wanda za'a iya gani a hoton da ke ƙasa - wayoyi guda biyu na ja. Akwai, ba shakka, shakkun cewa zai yi aiki. Gudun agogo yana da girma a 375 MHz kuma facin yana da muni. Amma tsarin ya jimre.
Duk kitchen din yayi kama.
Anan zaka iya ganin kwamfuta mai kyau tsarin I/O, allon FMC126P, da AD9208-3000EBZ mezzanine. Daga cikin janareta: janareta na 3000 MHz don rufe ADC, janareta na 770 MHz don REFCLK. Kebul tare da masu haɗin SMA suna haɗa janareta kuma suna ba da siginar shigarwa.
Matsakaicin saurin bayanai daga fitowar ADC, idan ba ku yi cikakken bayani ba, shine 12 GB/s daga tashoshi biyu. Dangane da ma'auni kuma bisa ga sanarwar masana'anta na allon FMC126P, matsakaicin saurin shigarwa shine 5 GB/s. Saboda haka, mun yi amfani da tashoshi ɗaya kawai a cikin ADC kuma mun wuce ta DDC (Digital Down Converter) da aka gina a cikin AD9208 tare da raguwa na hudu. Don haka, kwararar bayanai shine 3 GB/s (samfurin mitar 750 MHz, siginar hadaddun 16-bit).
Dubawa cewa tsarin yana da lokaci don yin rikodin samfuran abu ne mai sauqi qwarai: kawai kuna buƙatar saka idanu masu tsini na matsayin FPGA FIFO. Idan babu abubuwan da suka faru na FIFO a cikin dare, ba za a saita bit ɗin ba. Kuma cikin farin ciki mun bayyana cewa babu asarar karatu. Da farko mun bincika, ba shakka, cewa matakan latching suna aiki. Hakanan muna duban siginar siginar daga fayil ɗin don tabbatar da cewa ingancin siginar ADC ɗin da aka kama yayi daidai da takaddun.
Amma wane irin sigina ne zai cancanci irin wannan tsarin shigarwa? Tabbas UWB daga tebur na gaba!
An yi sa'a, mun zaɓi mitar tashar tashoshi 4 GHz don tsarin sakawa drone. Wannan yayi daidai da tashoshi 4 da 2 a cikin kalmomin DW1000 (Hoto na 13 na bayanan bayanai). Mun yi eriya da aka gina a cikin allo don wannan mitar, ko, mafi kyawun faɗi, don wannan kewayon. Ba abu mai sauƙi ba ne don daidaita shi a kan irin wannan faffadan makada. Amma abin ya zama na batsa! Wasu sun ce yana kama da alama ... tare da kunnuwa.
Sigina na 4 GHz tare da bandwidth 500 MHz yana faɗuwa a cikin rukunin Nyquist na uku kuma yana da isassun tazarar tsaro don gujewa haɗawa. Don haka, kawai mun haɗa siginar DW1000 zuwa shigar AD9208 ADC kai tsaye.
Mun karɓi fayiloli guda biyu: ɗaya tare da mitar PRF na 64 MHz, ɗayan - 16 MHz. An saita saurin watsawa zuwa mafi ƙarancin DW1000 - 110 kbit/s.
wannan file, wannan . Yi hankali, fayilolin suna da girma!
A cikin fayil na farko muna ganin fakiti masu ɗorewa game da samfurori 750 ko 1000 nanoseconds.
A cikin fayil na biyu, fakitin sun fi guntu sau huɗu.
Kuma wannan ya yi daidai da ma'aunin IEEE 802.15.4-2011 dangane da Layer na zahiri na UWB:
Na'urar daidaitawa a cikin fakitin yayi kama da daidaitawar lokaci, wanda kuma yayi daidai da wanda aka kayyade a ma'aunin BPSK. Kuna iya samun ma'aunin kanta akan Intanet, nemi "IEEE 802.15.4-2011".
Idan ka ɗan faɗaɗa taga lokacin kallo, Hakanan zaka iya ganin rashin daidaituwa na fakiti, wanda yayi daidai da bayanin IEEE 802.15.4-2011 UWB - matsayi-lokaci (BPM-BPSK).
Gabaɗaya, na sami guntu DW1000 da gyare-gyaren wannan UWB PHY a matsayin bam, duk abin da ke nufi, abu, a matakin JTIDS na soja. Wannan sabuwar sha'awa ce ta. A ci gaba!
A gefe guda, za mu haƙa DW1000, a ɗayan, za mu yi hulɗa da ma'aunin IEEE 802.15.4.
source: www.habr.com