Personal Equation and Its Variation-Discussion of Some Circumstances Causing Recorded Time of a Star's Transit to Differ from True Time

1911 ◽  
Vol 23 ◽  
pp. 167
Author(s):  
Elliott Smith
Keyword(s):  
PIERS Online ◽  
2008 ◽  
Vol 4 (4) ◽  
pp. 433-436 ◽  
Author(s):  
Yaping Liang ◽  
Calvin W. Domier ◽  
Neville C. Luhmann, Jr.

Author(s):  
Yakov Gutkin ◽  
Asher Madjar ◽  
Emanuel Cohen

Abstract In this paper, we describe the design, layout, and performance of a 6-bit TTD (true time delay) chip operating over the entire band of 2–18 GHz. The 1.15 mm2 chip is implemented using TSMC foundry 65 nm technology. The least significant bit is 1 ps. The design is based on the concept of all-pass network with some modifications intended to reduce the number of unit cells. Thus, the first three bits are implemented in a single delay cell. A peaking buffer amplifier between bit 4 and bit 5 is used for impedance matching and partial compensation of the insertion loss slope. The rms delay error of the TTD is <1 ps over most of the frequency band and insertion loss is between 2.5 and 6.3 dB for all 64 states.


2018 ◽  
Vol 36 (19) ◽  
pp. 4591-4601 ◽  
Author(s):  
Daniel Perez-Lopez ◽  
Erica Sanchez ◽  
Jose Capmany

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Shruti Vashist ◽  
M. K. Soni ◽  
P. K. Singhal

Rotman lenses are the beguiling devices used by the beamforming networks (BFNs). These lenses are generally used in the radar surveillance systems to see targets in multiple directions due to its multibeam capability without physically moving the antenna system. Now a days these lenses are being integrated into many radars and electronic warfare systems around the world. The antenna should be capable of producing multiple beams which can be steered without changing the orientation of the antenna. Microwave lenses are the one who support low-phase error, wideband, and wide-angle scanning. They are the true time delay (TTD) devices producing frequency independent beam steering. The emerging printed lenses in recent years have facilitated the advancement of designing high performance but low-profile, light-weight, and small-size and networks (BFNs). This paper will review and analyze various design concepts used over the years to improve the scanning capability of the lens developed by various researchers.


2004 ◽  
Vol 44 (1) ◽  
pp. 35-37 ◽  
Author(s):  
Sang-Shin Lee ◽  
Ho-Dong Chae ◽  
Do-Hwan Kim ◽  
Hyung-Joon Kim ◽  
Kwang-Taek Kim

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