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BPSK
milstar: Missions not requiring a residual carrier and having modest data rates (20 ks/s - 200 ks/s) should consider BPSK/NRZ modulation first. ######################## nonreturn-to-zero (NRZ) to binary phase-shift keying It provides a good compromise between spectrum efficiency and simplicity of design. While data imbalance does not result in system losses as in the case of PCM/PM/NRZ modulation, the statistics of each application should be reviewed. Agencies employing a DTTL architecture in their symbol synchronizers, must ensure a sufficient transition density to acquire and maintain synchronization. Manchester encoding prior to BPSK modulation can ensure sufficient transitions. As with PCM/PM/Bi-N modulation, there is a 100% penalty in spectrum efficiency over the NRZ equivalent https://deepspace.jpl.nasa.gov/files/phase3.pdf https://deepspace.jpl.nasa.gov/dsndocs/810-005/208/208B.pdf
milstar: https://pdfs.semanticscholar.org/eb38/48e2ba091a7445ef11acc084154062cf6d94.pdf shown. DPSK was shown to be an attractive robust alternative to coherent BPSK since only 1.5-4 dB energy penalties are incurred. For FSK, the energy penalty versus coherent BPSK was much larger as predicted by capacity analysis. The use of DPSK and noncoherent FSK is more strongly motivated on fading channels where coherent phase tracking is problematic. This application remains under s
milstar: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19660001034.pdf
milstar: C / N dB = 10 log (Eb/No) + 10 log (R / B) R information rate in bits per second; B channel bandwidth in Hertz; C total carrier power N total noise power in the bandwidth.
milstar: https://klevas.mif.vu.lt/~skersys/vsd/turbo/turbo-codec-qpsk-modem.pdf This proof–of–concept modem achieves a BER of 10–10 at an SNR of 2 dB (Rate 1/2 FEC) for data rates from 64 kbit/s up to 2,048 kbit/s using serial concatenated convolutional codes. Rate 1/2 and Rate 3/4 coding can be selected.
milstar: http://www.advantechwireless.com/wp-content/uploads/WP-Turbo-FEC-132191.pdf
milstar: LDR Payload: The LDR payload offers nearly 200 user channels and relays coded teletype and voice messages at data rates of 75 to 2400 bits per second. https://space.skyrocket.de/doc_sdat/milstar-1.htm To perform these complex functions, the MDR digital processing subsystem relies on 14 custom application-specific integrated circuits and 397 large-scale integrated (LSI) circuits, all fabricated in CMOS technology. This figure represents a decrease of 37 percent from the 630 custom LSI circuits required for each LDR payload. https://www.northropgrumman.com/Capabilities/MilstarPayloads/Pages/default.aspx the Milstar MDR payload can push data rates to 1.544 megabits per second. Or, by switching to lower data rates, it can receive signals from small, low-power ground terminals. Or it can operate at some intermediate combination of data rate and terminal power — all without sacrificing anti-jam performance.
milstar: The DSCS III satellite has six independent transponders (one per channel), three uplink antennas to receive signals from earth terminals, and five downlink antennas which retransmit the signals back to earth. The signal transmitted by the ground terminal is received at the satellite in the 7.9 to 8.4 GHz frequency range where it is amplified, down converted, and retransmitted in the 7.25 to 7.75 GHz frequency range. The DSCS III will replace the DSCS II satellites over a period of time. At this time, both are in orbit. The DSCS IIIs have some improvements over the DSCS IIs such as increased hardening, a nulling capability (antijam function), and more transponders. However, the DSCS III only has one NC gimballed dish antenna (GDA) http://www.bits.de/NRANEU/others/amd-us-archive/FM24-11%2890%29.pdf
milstar: 2 MARK RICE, TIM GILES, VOON WONG, ISMAIL SHAKEEL AND DOUG MEIN GROUND MOBILE WGS SATCOM FOR DISADVANTAGED TERMINALS operate at 7.9−8.4 GHz uplinks and 7.25−7.75 GHz downlinks, while the Ka-band beams operate at 30−31 GHz uplinks and 20.2−21.2 GHz downlinks, all in government allocated spectrum. Cross-banding is possible with WGS: X-band users can communicate with Ka-band users. https://www.researchgate.net/publication/228680490_Ground_Mobile_WGS_Satcom_for_Disadvantaged_Terminals MILCIS2009, CANBERRA, 10-12 NOVEMBER 2009 3 locations, 0.1% rain attenuation at Ka band has been found to vary from 20 dB to more than 50 dB, compared to only 0.4 dB to 4 dB at X band [4]
milstar: Defense officials have said DoD does not intent to replace most of its 17,000 satellite terminals. https://spacenews.com/commercial-satellite-roaming-possible-with-existing-military-terminals-experiment-shows/
milstar: https://www.rockwellcollins.com/~/media/Files/Unsecure/Products/Product%20Brochures/Communcation%20and%20Networks/SATCOM/Dket/DKET%20data%20sheet.aspx IF frequency X 950-1450 mhz Ku 950-1700 mhz Ka 1000-2000 mhz Applications FDMA, TDMA voice, video, data Modulation BPSK, QPSK, O QPSK, 8 PSK, 16 QAM Downlink frequency 7.25 - 7.75 GHz 10.95 - 12.75 GHz 20.20 - 21.20 GHz
milstar: На большинстве исследованных трасс имели место условия распространения, описываемые моделью тропосферного канала с релеевскими замираниями #################### https://pandia.ru/text/77/132/788.php
milstar: https://rit.informost.ru/rit/1-2007/rit-1-2007-50-56.pdf
milstar: https://army.informost.ru/2010/sbornik/3-70.pdf Предназначена для замены выработавших свой ресурс станций Р-410 и Р-412, для использования в разрабатываемых перспективных системах связи МО РФ на интервалах связи между объектами 100– 200 км и более https://army.informost.ru/2010/sbornik/3-70.pdf
milstar: https://pdfs.semanticscholar.org/cc7d/4930804a07b1cbf52d47e7d083eec9eee0ea.pdf
milstar: http://dsp7.ee.uct.ac.za/~nicolls/lectures/eee482f/04_chancap_2up.pdf
milstar: Unconstrained Shannon Limit for AWGN channel https://www.gaussianwaves.com/2008/04/channel-capacity/ https://www.ingenu.com/2016/07/back-to-basics-the-shannon-hartley-theorem/ Letting C/B=η (the spectral efficiency in (bits/seconds/Hz)), Here C is the maximum capacity of the channel in bits/second otherwise called Shannon’s capacity limit for the given channel, B is the bandwidth of the channel ##################### 0 bit/sek Eb/No = ln 2 =0.693147 ...= -1.6 db
milstar: BER Performance of OFDM-BPSK and -QPSK Over Generalized Gamma Fading Channel https://pdfs.semanticscholar.org/60f4/afa821965f0db67b78fddbbca34543979d1b.pdf
milstar: https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1053703
milstar: http://www.et.byu.edu/~beard/classes/ece682rweb/www-randy/files/goodpaper4-DivsalarSimon.pdf
milstar: . For general time-varying Rayleigh fading, however, ML-MSDD with low complexity is still an unsolved problem http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.83.3496&rep=rep1&type=pdf
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