где груши ? наполеон ... Связь /C3I/ (продолжение)

Форум » Дискуссии » где груши ? наполеон ... Связь /C3I/ (продолжение) » Ответить

где груши ? наполеон ... Связь /C3I/ (продолжение)

milstar: Прибытие прусского 4-го корпуса В 11 утра Блюхер двинулся из Вавра по труднопроходимым дорогам в сторону Ватерлоо. Груши еще был в Валене, в 11:30 он услышал первые выстрелы - это начался штурм Угумона. Груши все же предположил, что это стреляют арьергарды Веллингтона и не отменил наступление на Вавр. Генералы (Жерар) предлагали "идти на пушки"(на звук ################################################################################## стрельбы), но Груши не был уверен в правильности этого хода и не знал намерений Наполеона на свой счет. ############################################################################# В полдень авангард Бюлова находился в Шапель-Сен-Ламбер (6 километров от Планшенуа и 4 от фермы Папелотта). Цитен двигался примерно тем же путем - из Вавра в Оэн. Около 13:00 Блюхер был уже в Шапель-Сен-Ламбер и примерно через полчаса двинулся через болотистую долину на Планшенуа. В 16:00 Груши приблизился к Вавру и получил письмо Наполеона от 10 часов утра, ######################################################### в котором Наполеон одобрял движение к Вавру. Груши убедился, что поступает в соответствии с планами Наполеона. ################################################################################# Около 17:00 Груши получил письмо (от 13:30) с приказом идти на соединение с Наполеоном, ############################################################### но он уже втянулся в бой под Вавром. У его были все шансы разгромить генерала Тильмана, который предупредил об этом Блюхера. Тот ответил: "Пусть генерал Тильманн защищается, как только может. Его поражение в Вавре не будет иметь значения, если мы победим здесь" http://ru.wikipedia.org/wiki/%D0%91%D0%B8%D1%82%D0%B2%D0%B0_%D0%BF%D1%80%D0%B8_%D0%92%D0%B0%D1%82%D0%B5%D1%80%D0%BB%D0%BE%D0%BE

Ответов - 300, стр: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 All

milstar: radioljubitelskaja tochka zrenija na dinamicheskij diapazon ... toze polezna ,kak i rekord na 10 ghz s 10 watt 90 santimetrow diametrom antennoj -2000 km Conclusions When using the concept of dynamic range in Amateur Radio, we should refer to signals present simulta- neously at the antenna input. This means that BDR — implying that blocking means that the ability to copy the desired signal as blocked by a strong off-channel signal — for the FT-1000D is 96.5 dB. When the de- sired signal is placed at –77 dBm (see Note 2), the point of saturation, which was +20 dBm in QST (see Note 3) has to be compared to –77 dBm for a dy- namic range of 97 dB, ---------------------------------------- not to the MDS value measured under quite different circumstances. The value of 150 dB reported in QST is not the dynamic range for two simultaneously present signals. ------------------------------------------- It is the dynamic range for a single signal and is not of much inter- est to a radio amateur. http://www.sm5bsz.com/dynrange/qex/bdr.pdf Blocking Dynamic Range in Receivers An explanation of the different procedures and definitions that are commonly used for blocking dynamic range (BDR) measurements. By Leif Åsbrink, SM5BSZ Human sensors like the ears and the eyes have very large dynamic ranges, for example. The un- damaged ear can detect a 1 kHz sound wave at a level of 10–12 W/m2 while the upper limit is about 1 W/m2, where we start to feel pain. The dynamic range of our ears is thus about 120 dB. Our eyes can detect the light from a star in the dark sky when about ten pho- tons per second reach the retina, which converts to something like 10–13 W/m2. The Sun, with its 300 W/ m2, does not damage our eyes unless we look straight into it. Another example of dynamic range is the dynamic range of a vinyl music record. It may be on the order of 60 to 80 dB only, much less than the dy- namic range of our ears. The above examples show the dy- namic range for a single signal. ##################### The corresponding dynamic range for a receiver is not particularly interesting. ########################## Any room-temperature resistor pro- duces a noise voltage that would trans- fer –174 dBm/Hz to a matched cold resistor. ######################### With the RF preamplifier dis- abled, a typical HF receiver may pro- duce 20 dB more noise with a room- temperature dummy load at the input than would an ideal receiver that would not add any noise of its own (only amplifying the noise from the dummy load). A receiver adding 20 dB of noise is said to have a noise figure of 20 dB. If the bandwidth were 500 Hz, the noise floor referenced to the antenna input would be –174 + 20 + 27 dBm = –127 dBm. (Note that 10 log 500 ≈ 27.) This signal level is some- times improperly called MDS (mini- mum discernible signal) for such a typical receiver, even though a CW operator would easily copy a signal that is 10 dB weaker. Picking the noise floor as the low end of the dynamic range is typical for all dynamic ranges, not only in radio receivers. The noise floor power is pro- portional to the bandwidth and there- ######################### fore a receiver will have 10 dB more dynamic range when measured at a bandwidth of 200 Hz compared to when it is measured at a bandwidth of 2 kHz. ####################### It is the same receiver, though, and the dynamic range differ- ences that depend on bandwidth should not be included when different receivers are compared. For that reason, receivers should

milstar: . "Хорошо забытое старое" Andrу, N4ICK прислал мне копию статьи опубликованную в RCA в марте 1966 года под названием "Цифровые системы связи дальнего действия с использованием маломощных передатчиков". Некоторые инженеры RCA проектировали и тестировали крайне узкополосные коммуникационные системы на частоте около 15 мГц. Стабильность приемника составляла 1x10-7, а ионосферный Доплеровский сдвиг составлял величину в 1 Гц. Был использован радиопередатчик с питанием от батареи 9 Вольт и выходной мощностью 100 мВт, стабильность частоты которого равнялась всего лишь 1x10-6, что недостаточно для полосы пропускания приемника в 1 Гц. Поэтому были измерены только два параметра: 1. Частота передатчика имела дрейф свыше 20 Гц за каждые 20 секунд, а для попадания в полосу пропускания приемника дрейф частоты передатчика не должен быть больше +/- 10Гц. segodnja bez problem 2. Приемник имел 3 полосовых фильтра с полосой 17 Гц каждый. Это позволяло вести прием даже при дрейфе частоты до +/- 30Гц. Невыгодность этих двух параметров привела к снижению скорости передачи данных до 3 бит в 1 минуту. При 5-ти битном кодировании знаков это давало скорость 0.6 знаков в 1 минуту. Блок-диаграмма приемника показана слева. Это базовая схема в коммерческом приемнике с 1-й ПЧ 500 кГц. Далее эта частота преобразовывалась в ПЧ = 20 кГц и подавалась на ряд из 6-ти узкополосных фильтров охватывающих полосу частот от 19981 Гц to 20017 Гц. 32 bit AZP rabotajuschie na etix chastotax s THD - 120 db est Справа вы можете увидеть 100 мВт радиопередатчик. Ранее упоминалось, какой большой проблемой было устранение нестабильности его частоты. Генератор должен был находиться при постоянной окружающей температуре ... используя человеческое тело, как термостат. Кварцевый генератор находился в небольшой металлической коробке овальной формы, соединялся с передатчиком парой проводов. Для получения нужной температурной стабильности задающий генератор закреплялся в "подмышке" оператора. Измерения показали, что эта технология на 40db улучшает соотношение сигнал/шум (SNR) ############################################################## snizenie polosi .... по сравнению с традиционной техникой связи. http://www.cqham.ru/qrss.htm

milstar: Shannon–Hartley theorem Statement of the theorem Considering all possible multi-level and multi-phase encoding techniques, the Shannon–Hartley theorem states the channel capacity C, meaning the theoretical tightest upper bound on the information rate (excluding error correcting codes) of clean (or arbitrarily low bit error rate) data that can be sent with a given average signal power S through an analog communication channel subject to additive white Gaussian noise of power N, is: where C is the channel capacity in bits per second; B is the bandwidth of the channel in hertz (passband bandwidth in case of a modulated signal); S is the total received signal power over the bandwidth (in case of a modulated signal, often denoted C, i.e. modulated carrier), measured in watt or volt2; N is the total noise or interference power over the bandwidth, measured in watt or volt2; and S/N is the signal-to-noise ratio (SNR) or the carrier-to-noise ratio (CNR) of the communication signal to the Gaussian noise interference expressed as a linear power ratio (not as logarithmic decibels). http://en.wikipedia.org/wiki/Shannon-Hartley_theorem Examples 1.If the SNR is 20 dB, and the bandwidth available is 4 kHz, which is appropriate for telephone communications, then C = 4 log2(1 + 100) = 4 log2 (101) = 26.63 kbit/s. Note that the value of S/N = 100 is equivalent to the SNR of 20 dB. 4 khz * log po osnowaniju 2 (1+100) = 26.63 kbit/sek dlja SNR 0 db -4 kbit/sec dlja SNR 6 db (4raza) -8 kbit /sec dlja SNR 12 db (16 raz) -16 kbit/sec esli polosa 1 kgz =1000 gerz to sootw 1kbit/sek ,2 kbit/sec,4 kbit/sec esli 75 gerz to sootw 75bit/sec ,150 bit/sec,300 bit/sec

milstar: http://www.esstech.com/PDF/SABRE32%20ADC%20PF%20081218.pdf 32 bit ADC s THD -120 db ,dinamicheskij diapazon ochewidno boslche ... dlja realizacii sistem swjazi s wisokoj boewoj ystojchiwostju ... 75 bit/sec i polosoj signala do 100 gerz .

milstar: software defined radio 16 bit bolee chem 100 msps ADC prjamoe preobrazowanie ############################################################ http://winradio.com/home/g31ddc.htm Excellent sensitivity (0.35 µV SSB, 0.16 µV CW) Excellent dynamic range (107 dB typ.) ----- SSB - 2.4 -2.8 kghz ? Receiver type Direct-sampling, digitally down-converting software-defined receiver Frequency range 9 kHz to 49.995 MHz Tuning resolution 1 Hz Mode AM, AMS, LSB, USB, CW, FMN, FSK, UDM (user-defined mode) DRM mode optional Image rejection 90 dB typ. IP3 +31 dBm typ. Attenuator 0 - 21 dB, adjustable in 3 dB steps SFDR 107 dB typ. Noise figure 14 dB MDS -130 dBm @ 10 MHz, 500 Hz BW Phase noise -145 dBc/Hz @ 10 kHz RSSI accuracy 2 dB typ. RSSI sensitivity -140 dBm Processing and recording bandwidth (DDC bandwidth) 20 kHz - 2 MHz (selectable in 21 steps) Demodulation bandwidth (selectivity) 10 Hz - 62.5 kHz (continuously variable in 1 Hz steps) Spectrum analyzers Input spectrum/waterfall, 30 or 50 MHz wide, 1.5 kHz resolution bandwidth DDC spectrum/waterfall, max 2 MHz wide, 1 Hz resolution bandwidth Channel spectrum, max 62.5 kHz wide, 1 Hz resolution bandwidth Demodulated audio, 16 kHz wide, 1 Hz resolution bandwidth ADC 16 bit, 100 MSPS Sensitivity (typ. @ 10 MHz) AM -101 dBm (2.00 µV) @ 10 dB S+N/N, 30% modulation SSB -116 dBm (0.35 µV) @ 10 dB S+N/N, 2.1 kHz BW CW -123 dBm (0.16 µV) @ 10 dB S+N/N, 500 Hz BW FM -112 dBm (0.56 µV) @ 12 dB SINAD, 3 kHz deviation, 12 kHz BW, audio filter 300-3000 Hz, deemphasis -6dB/oct Tuning accuracy 0.5 ppm @ 25 °C Tuning stability 2.5 ppm (0 to 50 °C) MW filter Cut-off frequency 1.8 MHz @ -3 dB Attenuation 60 dB min @ 0.5 MHz Antenna input 50 ohm (SMA connector) Output 24-bit digitized I&Q signal over USB interface Interface USB 2.0 High speed Power supply 11-13 V DC @ 500 mA typ. 11-13 V DC @ 45 mA typ. (power save) Operating temperature 0 to 50 °C http://winradio.com/home/g31ddc-s.htm

milstar: radioljubitelskaja konstrukziaj s LTC 2208 130 msps 16 bit http://www.srl-llc.com/files/qs1r_revd_specs.pdf do 62 mgz ,s drugimi filtrami po 62 mgz naikwist zoni 186-248 mgz do 500 mgz (iz 16 bitnix ltc 2209 160msps w specificazii graafik s Fin do 700 mgz -eto lutschij resultat) http://www.srl-llc.com/files/qs1r_revd_specs.pdf http://www.srl-llc.com/

milstar: http://winradio.com/home/g315e-s.htm professionalnij primenik dlja srwnenija s SDR ot toj ze firmi (smotri wische)

milstar: Intelsat General selects XTAR to deliver X-band capacity to manpack terminals Nov 4, 2010 Posted by Courtney E. Howard ROCKVILLE, Md., 4 Nov. 2010. XTAR LLC, a U.S.-based commercial provider of satellite services in the X-band frequency, won a bandwidth contract from Intelsat General Corp. XTAR will provide Intelsat General with 16MHz of high-power, X-band services from its XTAR-LANT satellite stationed over the Atlantic Ocean. The capacity will be employed in support of military, mobile, manpack terminals prior to deployment into the field. The contract expands the relationship between the two companies that began with a master sales agreement in May. According to Kay Sears, president of Intelsat General, “This agreement with XTAR will enable both companies to satisfy the customer’s unique requirements for flexible and advanced X-band satellite capacity.” Philip Harlow, XTAR president and COO, hailed the contract award as a significant development in his company’s relationship with major satellite operator Intelsat General: “XTAR is committed to the success of all its customers by providing a superior experience which exceeds the unique mission requirements of governments worldwide. We are dedicated to providing highly secure, reliable services supported by consultative relationships and operational independence for our partners and clients.” XTAR-LANT, located at 30 degrees W, entered service in April 2006, carrying eight 100W wideband X-band transponders in both right- and left-hand circular polarization. The flexible payload makes it well suited for X-band services in North America for homeland security applications and enables one-hop connectivity to Europe and the Middle East. The satellite covers a large geographic area with two global beams and three spot beams that can be relocated within the satellite’s coverage area. “We continue to see demand for X-band services from U.S. and Allied governments to help fulfill their constantly growing need for high-capacity bandwidth to support a wide range of military applications, including communications on the move and high-capacity video among others,” Harlow states. “As governments keep looking to commercial providers for satellite bandwidth, they are increasingly turning to X-band providers as other frequency bands become more limited in availability. The X-band frequency is designated uniquely for government use and is therefore readily available to government customers without competition from commercial users, with no need to change user equipment from that normally used for WGS satellite operation.”

milstar: opisanie SDR i prinzipow ot amerikanskoj radioljubitelskoj associazii ... http://www.arrl.org/files/file/Technology/tis/info/pdf/020708qex035.pdf Milstar-2 imeet dwojnoe preobrazowanie chastoti . ##################################### Win radio predlagaet receiver s diapazonom 65 mgz ( mozno do 500 meg po 65 mgz ,menjaa filtri ) 16 bit 130 msps LTC2208 bez kakix -libo smesitelej Pri neobxodimosti poluchenija maximalnix parametrow po dinamike ,chustwitelnoisti w ghz diapazone chansi priiemnikow s prjamoj konwersiej kak winradio w blizajschee wremja minimalni ############### lutschij 16 bit AD9467 imeet Fin 300 mgz i SFDR 93 db Na grafikax LTC2209 16 bit normirowanna Fin do 500 mgz ,no SNR i SFDR padaet 93 db eto wesma posredstwennij dinamicheskij diapazon ########################################## tem bole ,chto polosa dlja rascheta etogo diapazona ne bolee 10 kgz ( a skoree 2400 gerz) Radari proekta Appolo s antenanami 3.9 i 9 metrow imeli dinmaicheskij diapazon w C band 5.8 gigagerz bolee 120 db bolee 40 let nazad Eto dlja polosi ,kotoraja jawno boslche ! Maximum do 8 megagerz .

milstar: http://www.flex-radio.com/Products.aspx?topic=SDR_Feature_Matrix radilojubitelskoe SDR do 60 mgz .Oni ispolzujut 24 bit ADC ,t.e. promezutochnaja chastota tam est .... http://www.youtube.com/watch?v=KYMr07jTtLs&feature=related

milstar: ADC Selection As I mentioned earlier, this is currently the weakest link in the receiver. Any improvements in the ADC can be translated directly to a better IP3. This is why traditional IF-DSP receivers ############################# have used low IFs. It allows the use of 16- to 24-bit ADCs that have excellent ########################### specifications. http://www.arrl.org/files/file/Technology/tis/info/pdf/020708qex035.pdf

milstar: Schumowaja temperatura antenni 120 -180 sm w diapazonax 10-14 ghz .W zawisimosti ot ygla elevazii 41 -83 Kelvina http://www.gdsatcom.com/Antennas/Data_Sheets/655-0087A_C120M.pdf http://www.gdsatcom.com/Antennas/Data_Sheets/655-0084A_C180M.pdf iz yglewolokna ,w tom chisle ina 20-30 ghz http://www.gdsatcom.com/Antennas/Data_Sheets/6550064D_1.2QDMA.pdf ot 56 k do 182 k w zawisimosti ot ygla elevazii i diapazona ( wische ygol i diapazon -wische schumowaja temperatura) 67 sm ,Ka band http://www.gdsatcom.com/Antennas/Data_Sheets/3670spec.pdf

milstar: http://amateurradio.com.au/node/1263 World 10 GHz SSB distance record August 1, 2010 by Arvadmin On 10 July a contact on 10 GHZ between the island of Sal in Cape Verde and Portugal set a new world distance record of 2696 km. ################################################################################### Eto skoree 90 sant. antenna ,10 watt ,2100 gerz polosa signala ,troposfernoe proxozdenie smotri foto http://www.hyperatlantica.ch/ 1.Woennie helix twt lampi (ot Trident-2 terminal ?) pri wese 1.8 kg imejut sredn.moschnost 300-1000 watt i oktawnij diapzon http://www.l-3com.com/eti/news/600w.htm L-3 ETI to Develop 600W Ka-Band Traveling Wave Tube for the U.S. Air Force http://www.l-3com.com/eti/product_lines_military_twt.htm smotri 8909 h 2. Kriogennowoe oxlazdenie dowlno legko sejtshas 3 .Snizenie skorosti signala do 75 bit /sec,1 bit /sec , ... do 0.1 bit/sec wmesto 2100 gerz i sootw. polosi signala -dop .wiigrisch 2100 proti 2.1 gerza -30 db Just two hours earlier a distance of 2,220 km was achieved breaking the previous world record of 2,079 km. As part of an expedition "HYPERATLANTICA 2010" D44/HK86NU and set the new world record by contacting a team in CT7 consisting of F1PYR and F6DPH. The Hepburn Tropo Index map at the time indicated success was possible over that path.

milstar: Swiss Hams Set New World Record on 10 GHz TAGS: gps coordinates 08/02/2010 A group of six Swiss hams have set a new record for the longest contact (based on GPS coordinates) made on 10 GHz using SSB -- 2696 km (1675 miles): from Ilha do Sal (one of the northern Cape Verde islands) to Portugal. Using a 20 W transmitter -- with a 90 cm parabolic reflector with 35 dB gain -- these hams, part of the Hyperatlantica 2010 DXpedition, were able to contact Portugal on the morning of July 10 for almost 25 minutes. The original record of 2070 km (1286 miles) -- set in 2000 by Armin Martsch, DL4AM, and Adalbert Kaufmann, DJ3KM -- was broken by the Swiss group earlier that same day, with a contact between Ilha do Sal and Tangier, Morocco at a distance of 2200 km (1367 miles). http://www.arrl.org/news/view/swiss-hams-set-new-world-record-on-10-ghz

milstar: Около 17:00 Груши получил письмо (от 13:30) с приказом идти на соединение с Наполеоном, ############################################################### но он уже втянулся в бой под Вавром ... Gruschi widwigajtes k Ygumonu w maximalnom tempe ... s pomsochju 10 bit mozno yporjadochit 1024 podobnix prikaza SSB wische eto 2100 herz polosa sniziw polosu do 0.21 herza -wiigrisch po signal schum 40 db ############################################# ykazanie wische 10 bit mozno peredat za odnu minutu dlja komnatnoj temperaturi schum pri polose 1herz -174 dbm pri 0 Kelvina -204 dbm

milstar: Italjanskij rekord - 304 km ... 5.7 ghz no dlja polosi 5 mgz ! 12-48 mbps ----------------------------------------------------- http://forum.mikrotik.com/viewtopic.php?f=7&t=16548 Italy The longest unamplified Wi-Fi link is a 304 km link[8] achieved by CISAR [9] (Center for Radio Activities) in Italy. link established on 16-06-2007 frequency: 5765 MHz IEEE 802.11a (Wi-Fi), bandwidth 5 MHz Radio: Ubiquiti Networks XR5 Wireless routers: MikroTik RouterBOARD with RouterOS, NStreme optimization enabled Length: 304 km (189 mi). Antenna is 120 cm Satellite dish prime focus with handmade waveguide. 35dBi estimated http://en.wikipedia.org/wiki/Long-range_Wi-Fi

milstar: powtor For a 1 Hz bandwidth and at 290 K: Pn = 1.38 * 10-23 * 290 * 1 Pn = 4 * 10-21 Watts Pn = -174 dBm For a 1 Hz bandwidth and at 1 K: Pn = 1.38 * 10-23 Watts Pn = -198 dBm za schet kriogenowogo oxlazdenija mozno wiigrat do 20 db ####################################### http://www.qsl.net/n9zia/receiver.html The wider the bandwidth, the greater the noise power and the higher the noise floor ######################################################## Consider a receiver that has a 1 MHz bandwidth and a 20 dB noise figure. If a S/N of 10 dB is desired, the sensitivity (S) is: S = -174 + 20 + 10log101,000,000 + 10 S = -84 dBm It can be seen from this that if a lower S/N is required, better receiver sensitivity is necessary. If a 0 dB S/N is used, the sensitivity would become -94 dBm. The -94 dBm figure is the level at which the signal power equals noise power in the receiver's bandwidth. If the bandwidth were reduced to 100 kHz while maintaining the same input signal level, the output S/N would be increased to 10 dB due to noise power reduction. ------- dlja RLS ispolzuemoj w Appolo proekt IF polosa bila 8 mgz ########################################## a S/N receiver bilo polutsche na 8db -10 t.e. w formule nize a. yxudschit na 8 db za schet raschirenija polosi s 1 mgz do 8 mgz b. ylutschit na 8 db za chet lutschej schumowoj xarakteristiki Consider a receiver that has a 1 MHz bandwidth and a 20 dB noise figure. If a S/N of 10 dB is desired, the sensitivity (S) is: S = -174 + 20 + 10log101,000,000 + 10 S = -84 dBm ############## A dinamicheskij diapazon bolee 120 db ...

milstar: klassischeskij priemnik predstawitelej wtoroj drewnejschej 80 godow Watkins Johnson WJ-8617B http://watkins-johnson.terryo.org/Documents/Manufacturers/WJ/Data%20sheets/WJ-8617B%20data%20sheet.pdf Schum -9.5 db ,Imagei If rejection -90 db ,chustwit dlja polosi 10 kgz -104 dbm ili dlja polosi 1 kgz -114 dbm

milstar: conversija microvolt w dbm For the common situation where R=50, this simplifies to (9) dBm = 20 LOG Eµ - 107 Emju w mirovoltax esli priemnik imeet chustwitelnost 0.25 microvolt pri signal / k schumam i iskazenijam 12 db ############################################################### to 0.25 microvolta = -119 dbm ili 149 dbwatt i pri etom naprjazenii signala na wixode poleznij signal na 12 db(po moschnsoti 16 raz ,po napr 4 raza ) wische chem schum eto dlja polosi 1000 gerz A SINAD of 12-dB should provide a comfortable margin for copying voice communications. A skilled listener can probably copy voice signals which have a signal to noise ratio of much less than 12-dB. Very skilled listeners can copy voice signals which are at or below the noise level. http://continuouswave.com/whaler/reference/dBm.html http://continuouswave.com/whaler/reference/VHF.html http://continuouswave.com/ubb/Forum6/HTML/001847.html -------------------------------------------------------------------------- http://tscm.com/rcvr_sen.pdf Receiver sensivity /noise -114 dbm dlja polosi 1mgz pri komnatnoj temperature -174 db dlja polosi 1 gerz Minimum S/N 1.Dlja optinogo operatora z displeem 3-8 db 2.Awtodetekzija 10-14 db tipichnaja chustw . a. RWR -radar warning reciever -65 dbm (bolschaja polosa) b. Pulse radar -94dbm v. Missile seeker - 138 dbm idealnij primenik pri komnatnoj temperature 1 gerz -204 dbw ili -174 dbm 1khz -174 dbw ili -144 dbm 1mgz -144 dbw ili -114 dbm 1mgz -114 dbw ili -84 dbm tipichnij radar priemnik trebuet 3-10 db otlichit signal ot schumow i 10-20 db to tracj ------------------------ Conclusions When using the concept of dynamic range in Amateur Radio, we should refer to signals present simulta- neously at the antenna input. This means that BDR — implying that blocking means that the ability to copy the desired signal as blocked by a strong off-channel signal — for the FT-1000D is 96.5 dB. When the de- sired signal is placed at –77 dBm (see Note 2), the point of saturation, which was +20 dBm in QST (see Note 3) has to be compared to –77 dBm for a dy- namic range of 97 dB, ---------------------------------------- not to the MDS value measured under quite different circumstances. The value of 150 dB reported in QST is not the dynamic range for two simultaneously present signals. ------------------------------------------- It is the dynamic range for a single signal and is not of much inter- est to a radio amateur. http://www.sm5bsz.com/dynrange/qex/bdr.pdf Blocking Dynamic Range in Receivers An explanation of the different procedures and definitions that are commonly used for blocking dynamic range (BDR) measurements. By Leif Åsbrink, SM5BSZ Human sensors like the ears and the eyes have very large dynamic ranges, for example. The un- damaged ear can detect a 1 kHz sound wave at a level of 10–12 W/m2 while the upper limit is about 1 W/m2, where we start to feel pain. The dynamic range of our ears is thus about 120 dB. Our eyes can detect the light from a star in the dark sky when about ten pho- tons per second reach the retina, which converts to something like 10–13 W/m2. The Sun, with its 300 W/ m2, does not damage our eyes unless we look straight into it. Another example of dynamic range is the dynamic range of a vinyl music record. It may be on the order of 60 to 80 dB only, much less than the dy- namic range of our ears. The above examples show the dy- namic range for a single signal. ##################### The corresponding dynamic range for a receiver is not particularly interesting. ########################## Any room-temperature resistor pro- duces a noise voltage that would trans- fer –174 dBm/Hz to a matched cold resistor. ######################### With the RF preamplifier dis- abled, a typical HF receiver may pro- duce 20 dB more noise with a room- temperature dummy load at the input than would an ideal receiver that would not add any noise of its own (only amplifying the noise from the dummy load). A receiver adding 20 dB of noise is said to have a noise figure of 20 dB. If the bandwidth were 500 Hz, the noise floor referenced to the antenna input would be –174 + 20 + 27 dBm = –127 dBm. (Note that 10 log 500 ≈ 27.) This signal level is some- times improperly called MDS (mini- mum discernible signal) for such a typical receiver, even though a CW operator would easily copy a signal that is 10 dB weaker. Picking the noise floor as the low end of the dynamic range is typical for all dynamic ranges, not only in radio receivers. The noise floor power is pro- portional to the bandwidth and there- ######################### fore a receiver will have 10 dB more dynamic range when measured at a bandwidth of 200 Hz compared to when it is measured at a bandwidth of 2 kHz. ####################### It is the same receiver, though, and the dynamic range differ- ences that depend on bandwidth should not be included when different receivers are compared. For that reason, receivers should

milstar: Stat*ja Triquint (GaAS dlja Radarow ,kommunikazij) i Watkins Johnson o dinamicheskom diapazone priemnikow http://www.triquint.com/prodserv/tech_info/docs/WJ_classics/vol14_n1.pdf http://www.triquint.com/prodserv/tech_info/docs/WJ_classics/vol14_n2.pdf

полная версия страницы