Spectral-Selective Radiometer Unit with Radio-Interference Protection

Grenkov, S. A.; Kol’tsov, N. E.

doi:10.1007/s11141-015-9625-y

Cited by 6 publications

(2 citation statements)

References 3 publications

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“…This will provide compatibility with the "legacy" backends and allow us to upgrade RT-32 antennas with MDBE. It also implies that at least two single-dish modes will be designed for MDBE to provide spectrometric observations [25] and radiometric observations with frequency domain RFI rejection [26].…”

Section: Current Firmware Design Resultsmentioning

confidence: 99%

Multifunctional Digital Backend for Quasar VLBI network

Nosov¹,

Marshalov²,

Fedotov³

et al. 2021

J. Inst.

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The new 13-meters radio telescope recently built at Svetloe observatory (Russia) required a backend device that could digitize wideband signals from the receiving system, process the signal appropriately, prepare and transmit the resulting signal to the recorder. The previously existing backends, also used at other radio telescopes of Quasar VLBI network, could not provide compatibility with VGOS (VLBI Global Observing System) requirements. We developed Multifunctional Digital Backend (MDBE) with superior performance, flexibility and functions to equip the new antenna and other radio telescopes of the network with the same backend compatible with both domestic and international systems. The MDBE contains up to 12 input channels with 2 GHz bandwidth, powerful and remotely configurable Field programmable gate arrays (FPGA) for digital signal processing, and optical transceivers with total throughput of 50 Gbps per channel. The digital downconverters implemented in FPGA can form sub channels with 0.5, 2, 4, 8, 16, and 32 MHz bandwidth freely tuned with 10 kHz step. In wideband mode a single channel with 512, 1024 or full 2048 MHz bandwidth can be recorded. The MDBE also supports single-dish applications, such as radiometric and spectrometric observations. The paper presents the results of hardware and firmware development of the system, and the experimental results received with the MDBE in Svetloe observatory.

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Section: Current Firmware Design Resultsmentioning

confidence: 99%

Multifunctional Digital Backend for Quasar VLBI network

Nosov¹,

Marshalov²,

Fedotov³

et al. 2021

J. Inst.

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show abstract

“…Moreover, future sensors need to use these unprotected bands in order to achieve a specific observation target [22]. This results in fueling a great deal of research into RFI identification in spaceborne microwave radiometer measurements [23][24][25][26][27][28][29][30], and a series of identification methods for this purpose having been proposed [14][15][16][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Detection and Analysis of C-Band Radio Frequency Interference in AMSR2 Data over Land

Qian

Bao

et al. 2019

Remote Sensing

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A simplified generalized radio frequency interference (RFI) detection method and principal component analysis (PCA) method are utilized to detect and attribute the sources of C-band RFI in AMSR2 L1 brightness temperature data over land during 1–16 July 2017. The results show that the consistency between the two methods provides confidence that RFI may be reliably detected using either of the methods, and the only difference is that the scope of the RFI-contaminated area identified by the former algorithm is larger in some areas than that using the latter method. Strong RFI signals at 6.925 GHz are mainly distributed in the United States, Japan, India, Brazil, and some parts of Europe; meanwhile, RFI signals at 7.3 GHz are mainly distributed in Latin America, Asia, Southern Europe, and Africa. However, no obvious 7.3 GHz RFI appears in the United States or India, indicating that the 7.3 GHz channels mitigate the effects of the C-band RFI in these regions. The RFI signals whose position does not vary with the Earth azimuth of the observations generally come from stable, continuous sources of active ground-based microwave radiation, while the RFI signals which are observed only in some directions on a kind of scanning orbit (ascending/descending) mostly arise from reflected geostationary satellite signals.

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Detection of radio signals against the background of strong electromagnetic noise in transport

Myasnikov

Zaboronkova

Kogan

2021

J. Phys.: Conf. Ser.

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The problem of detecting a useful signal in the presence of a strong background noise is considered. To solve it, a statistical approach is used, based on a change in the level of chaos in the system when an additional random or deterministic process occurs, which is probabilistically independent from a set of stochastic phenomena that form background noise. It is shown that the occurrence of this process changes the level of entropy of the measured signal; this fact is the basis of the applied mathematical algorithm. It is based on the elements of the Fourier transform apparatus for the probability density with an appropriate choice of a nonlinear function of the random process under study. The proposed approach, based on variations in the randomness in the system in the presence of a useful signal, makes it possible to record its presence against the background of noise components even at low signal-to-noise ratios. The effectiveness of the method is confirmed both by theoretical justification and by the calculations presented in this work. The condition for the implementation of the technique described in the article, which does not impose restrictions on the studied physical fields and frequency ranges, is the comparability of the width of the probabilistic distribution of the desired useful signal with several intervals of discreteness of the measuring equipment. One of the results of this work is a high sensitivity to the emergence of independent random components.

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Spectral-Selective Radiometer Unit with Radio-Interference Protection

Cited by 6 publications

References 3 publications

Multifunctional Digital Backend for Quasar VLBI network

Multifunctional Digital Backend for Quasar VLBI network

Detection and Analysis of C-Band Radio Frequency Interference in AMSR2 Data over Land

Detection of radio signals against the background of strong electromagnetic noise in transport

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