• Journal of the Korean Society of Radiology
• /
• v.14 no.4
• /
• pp.487-494
• /
• 2020

The distance between the source and the detector, the diameter of the detector, and the volume effect of the radiation source result in a change in solid angle at the detector entrance, which affects the determination of detection efficiency by causing a difference in path length within the detector. A typical analysis method for calculating solid angles was useful only for a source (⁶⁰Co) with a simple geometric structure, so in this experiment, the distance between the detector and the source was measured by switching on for up to 25 cm with the reference point of window cap 0.5 cm. In addition, 450 and 1000 ㎖ Marinelli beaker of standard volumetric sources were closely adhered to the detector. For circular point sources co-axial with the detector, the change in the solid angle to the distance from the detector window is equal to half the square radius of the source versus the square radius of the detector, if the resulting relationship of the calculation analysis results in the detector being less than the radius of the source. Since the solid angular difference is 0.5 the result of Monte Carlo is acceptable. The relationship between detector and source distance is shown. Solid angles have been verified to decrease rapidly with distance. Measurement and simulation results for a volumetric source show a difference of ±1.01% from a distance of 0 cm and less than 4 % when the distance is reduced to 5 and 10 cm. It can be seen that the longer distance, the smaller efficiency angle, and the exponential increase in attenuation as the energy decreases, is reflected in the calculation of efficiency. Thus, the detection efficiency has proved sufficient for the use of solid angle and Monte Carlo codes.

• Proceedings of the IEEK Conference
• /
• 2000.06b
• /
• pp.217-220
• /
• 2000

In this paper, A low-power MOS monolithic peak detector is presented. Designed for monolithic and low-power characteristics, this MOS peak detector can be integrated easily on the same chip as a module of large communication systems. The simulation results of this peak detector which was composed with four NMOSs and two capacitors show the power dissipation of 0.972㎽ and the good operations for 2㎓ operating pulse frequency. Therefore, it may be used as a functional block for various signal processing systems.

• Proceedings of the IEEK Conference
• /
• 2000.06a
• /
• pp.201-204
• /
• 2000

In this paper, a new multiuser detector combining multicarrier and decorrelating detection schemes is proposed and analyzed in a frequency selective Rayleigh fading channel. The bit error probability is derived and compared with that of the conventional decorrelating detector. From the numerical results, it is shown that the proposed detector achieves better BER performance and lower computational complexity than those of the conventional decorrelating detector.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.687-690
• /
• 1998

The full Viterbi detector for EPRML read channel system needs large area due to complex computation. There are several conventional methods to reduce the complexity such as GVA(Generalized Viterbi Algorithm) and BMS(Branch Metric Shift). This paper proposes another method, FVD(Folding Viterbi Detector), that has state transition diagram folded with inverted states. Compared with GVA detector, FVD requires only 61% gates and has lower power consumption and better BER performance.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.447-448
• /
• 2008

This paper presents a low-complexity design and implementation results of a multi-input multi-output (MIMO) orthogonal frequency division multiplexing (OFDM) symbol detector for high speed wireless LAN (WLAN) systems. The proposed spatial division multiplexing (SDM) symbol detector is designed by HDL and synthesized to gate-level circuits using 0.18um CMOS library. The total gate count for the symbol detector is 238K.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.4 no.2
• /
• pp.16-21
• /
• 1967

This report describes actual fabrication mehod of Li drifted Ge detector. The gamma-ray spectrum from Cl(n, r) reaction measured by this Li drifted Ge detector are also shown. Energy resolution(FWHM) of this Li drifted Ge detector is 4.5KeV at the 122KeV( ), and 10KeV a the 1333KeV( ) respectively.

• Proceedings of the IEEK Conference
• /
• 2001.06b
• /
• pp.57-60
• /
• 2001

A readout circuit for Dual band IR detector was proposed and designed. Designed circuit provide to detector a stable diode bias and high injection efficiency using Buffered Direct Injection (BDI) input circuit. Then, amplifier in the unit cell is operated when cell is selected in order to minimize the power consumption. We could confirm through the simulation that designed circuit integrate and output simultaneously the signal generating from the dual band IR detector.

• Journal of Communications and Networks
• /
• v.16 no.5
• /
• pp.485-492
• /
• 2014

Spectrum sensing for cognitive-radio applications may use a matched-filter detector (in the presence of full knowledge of the signal that may be transmitted by the primary user) or an energy detector (when that knowledge is missing). An intermediate situation occurs when the primary signal is imperfectly known, in which case we advocate the use of a linear-quadratic detector. We show how this detector can be designed by maximizing its deflection, and, using moment-bound theory, we examine its robustness to the variations of the actual probability distribution of the inaccurately known primary signal.

• Nuclear Engineering and Technology
• /
• v.29 no.6
• /
• pp.451-458
• /
• 1997

Signal shapes from a closed-ended coaxial HPGe detector are investigated by numerical methods. The detector used in this study has a volume of 72 ㎤ with relative efficiency of 15%. The electric field and potential distributions in the detector are determined by solving the Poisson equation at the depletion and operating bias. Hence the time dependent signal shapes induced on the electrode are obtained from the energy balance consideration and tv solving the equation of motion for the charge carriers. For various initial positions of a charge carrier pair, the collection times of induced charge vary in the range of 70 - 404 nsec.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.12 no.5
• /
• pp.428-438
• /
• 1987

This paper describesl the point-detector arrays system to processes the field of signal and noise of the turbulent atmosphere or variance and covariance circuit. By using the aboves, the maximum output of direct-detection shows a little differences between experimental datas. As a whole the experimental data datas are agreed with the joint Gaussian theoretical curves.