scholarly journals Wideband RFI Cancellation for High-sensitivity Phased Array Receivers with True Time Delays and Truncated Hadamard Projection

2021 ◽  
Author(s):  
Jakob Kunzler
Keyword(s):  
Phased Array ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Digital Signal ◽  
Wide Band ◽  
Hadamard Transform ◽  
Subspace Projection ◽  
True Time ◽  
Analog Circuitry ◽  
Analog Domain

<div>Radio frequency interference (RFI) is a significant challenge for high-sensitivity phased array instruments. RFI can be suppressed using digital signal processing, but to improve dynamic range for wideband RFI, it can be desirable to remove interference in the analog domain before sampling. In previous work, it has been shown that analog true time delay (TTD) stages with a truncated Hadamard transform can place a wide-band spatial null on RFI from a given direction of arrival. We show that TTD and Hadamard projection is mathematically equivalent to the classical, narrow-band subspace projection beamformer, but with a structure that allows efficient implementation in analog circuitry. Simulation results show that TTD and Hadamard projection can place deep nulls on wideband RFI signals and still achieve SNR performance comparable to the optimal digital maximum signal to interference and noise ratio beamformer.</div>

scholarly journals Wideband RFI Cancellation for High-sensitivity Phased Array Receivers with True Time Delays and Truncated Hadamard Projection

2021 ◽  
Author(s):  
Jakob Kunzler
Keyword(s):  
Phased Array ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Digital Signal ◽  
Wide Band ◽  
Hadamard Transform ◽  
Subspace Projection ◽  
True Time ◽  
Analog Circuitry ◽  
Analog Domain

<div>Radio frequency interference (RFI) is a significant challenge for high-sensitivity phased array instruments. RFI can be suppressed using digital signal processing, but to improve dynamic range for wideband RFI, it can be desirable to remove interference in the analog domain before sampling. In previous work, it has been shown that analog true time delay (TTD) stages with a truncated Hadamard transform can place a wide-band spatial null on RFI from a given direction of arrival. We show that TTD and Hadamard projection is mathematically equivalent to the classical, narrow-band subspace projection beamformer, but with a structure that allows efficient implementation in analog circuitry. Simulation results show that TTD and Hadamard projection can place deep nulls on wideband RFI signals and still achieve SNR performance comparable to the optimal digital maximum signal to interference and noise ratio beamformer.</div>

Design of a Front-End for Satellite Receiver

2016 ◽  
Vol 6 (5) ◽  
pp. 2282 ◽  
Author(s):  
Tran Van Hoi ◽  
Ngo Thi Lanh ◽  
Nguyen Xuan Truong ◽  
Nguyen Huu Duc ◽  
Bach Gia Duong
Keyword(s):  
Dynamic Range ◽  
Noise Figure ◽  
High Sensitivity ◽  
Wide Band ◽  
Local Oscillator ◽  
Low Noise ◽  
Voltage Controlled Oscillator ◽  
Front End ◽  
L Band ◽  
Satellite Receiver

<p>This paper focuses on the design and implementation of a front-end for a Vinasat satellite receiver with auto-searching mechanism and auto-tracking satellite. The front-end consists of a C-band low-noise block down-converter and a L-band receiver. The receiver is designed to meet the requirements about wide-band, high sensitivity, large dynamic range, low noise figure. To reduce noise figure and increase bandwidth, the C-band low-noise amplifier is designed using T-type of matching network with negative feedback and the L-band LNA is designed using cascoded techniques. The local oscillator uses a voltage controlled oscillator combine phase locked loop to reduce the phase noise and select channels. The front-end has successfully been designed and fabricated with parameters: Input frequency is C-band; sensitivity is greater than -130 dBm for C-band receiver and is greater than -110dBm for L-band receiver; output signals are AM/FM demodulation, I/Q demodulation, baseband signals.</p>

scholarly journals Design of a Front-End for Satellite Receiver

2016 ◽  
Vol 6 (5) ◽  
pp. 2282
Author(s):  
Tran Van Hoi ◽  
Ngo Thi Lanh ◽  
Nguyen Xuan Truong ◽  
Nguyen Huu Duc ◽  
Bach Gia Duong
Keyword(s):  
Dynamic Range ◽  
Noise Figure ◽  
High Sensitivity ◽  
Wide Band ◽  
Local Oscillator ◽  
Low Noise ◽  
Voltage Controlled Oscillator ◽  
Front End ◽  
L Band ◽  
Satellite Receiver

<p>This paper focuses on the design and implementation of a front-end for a Vinasat satellite receiver with auto-searching mechanism and auto-tracking satellite. The front-end consists of a C-band low-noise block down-converter and a L-band receiver. The receiver is designed to meet the requirements about wide-band, high sensitivity, large dynamic range, low noise figure. To reduce noise figure and increase bandwidth, the C-band low-noise amplifier is designed using T-type of matching network with negative feedback and the L-band LNA is designed using cascoded techniques. The local oscillator uses a voltage controlled oscillator combine phase locked loop to reduce the phase noise and select channels. The front-end has successfully been designed and fabricated with parameters: Input frequency is C-band; sensitivity is greater than -130 dBm for C-band receiver and is greater than -110dBm for L-band receiver; output signals are AM/FM demodulation, I/Q demodulation, baseband signals.</p>

scholarly journals Design of 4-Bit TDL(True-Time Delay Line) for Elimination of Beam-Squint in Wide Band Phased-Array Antenna

2009 ◽  
Vol 20 (10) ◽  
pp. 1061-1070
Author(s):  
Sang-Keun Kim ◽  
Min-Kil Chong ◽  
Su-Bum Kim ◽  
Hyung-Gi Na ◽  
Se-Young Kim ◽  
...  
Keyword(s):  
Time Delay ◽  
Phased Array ◽  
Delay Line ◽  
Wide Band ◽  
Array Antenna ◽  
Phased Array Antenna ◽  
True Time Delay ◽  
True Time

Slow-Scan CCD Observation of Backscattering Patterns in SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1308-1309
Author(s):  
F. Ouyang ◽  
D. A. Ray ◽  
O. L. Krivanek
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Lens System ◽  
Wide Dynamic Range ◽  
Peltier Cooler ◽  
Diffraction Patterns ◽  
Scanning Electron

Electron backscattering Kikuchi diffraction patterns (BKDP) reveal useful information about the structure and orientation of crystals under study. With the well focused electron beam in a scanning electron microscope (SEM), one can use BKDP as a microanalysis tool. BKDPs have been recorded in SEMs using a phosphor screen coupled to an intensified TV camera through a lens system, and by photographic negatives. With the development of fiber-optically coupled slow scan CCD (SSC) cameras for electron beam imaging, one can take advantage of their high sensitivity and wide dynamic range for observing BKDP in SEM.We have used the Gatan 690 SSC camera to observe backscattering patterns in a JEOL JSM-840A SEM. The CCD sensor has an active area of 13.25 mm × 8.83 mm and 576 × 384 pixels. The camera head, which consists of a single crystal YAG scintillator fiber optically coupled to the CCD chip, is located inside the SEM specimen chamber. The whole camera head is cooled to about -30°C by a Peltier cooler, which permits long integration times (up to 100 seconds).

Development of imaging plate for a TEM and its characteristics

1989 ◽  
Vol 47 ◽  
pp. 100-101
Author(s):  
N. Mori ◽  
T. Oikawa ◽  
Y. Harada ◽  
J. Miyahara ◽  
T. Matsuo
Keyword(s):  
Dynamic Range ◽  
Protective Layer ◽  
High Sensitivity ◽  
Imaging Plate ◽  
Phosphor Layer ◽  
Imaging Device ◽  
X Ray Imaging ◽  
New Type ◽  
Basic Characteristics ◽  
Reading System

The Imaging Plate (IP) is a new type imaging device, which was developed for diagnostic x ray imaging. We have reported that usage of the IP for a TEM has many merits; those are high sensitivity, wide dynamic range, and good linearity. However in the previous report the reading system was prototype drum-type-scanner, and IP was also experimentally made, which phosphor layer was 50μm thick with no protective layer. So special care was needed to handle them, and they were used only to make sure the basic characteristics. In this article we report the result of newly developed reading, printing system and high resolution IP for practical use. We mainly discuss the characteristics of the IP here. (Precise performance concerned with the reader and other system are reported in the other article.)Fig.1 shows the schematic cross section of the IP. The IP consists of three parts; protective layer, phosphor layer and support.

Sign in / Sign up

Export Citation Format

Share Document