• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.180-185
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• 2000

In this paper, we designed 2303.15MHz Sequency synthesizer for the purpose of the phase noise prediction. For the modeling of phase noise Oersted in the designed system through inooducing the noise-modeling method suggested by Lascari we analyzied a variation of phase noise as according as that of offest frequency. Especially, for the third-order system of the PLL among some kinds of phase noise generated from VCO we analyzed the aspect of 1/f-noise appearing troubles in the low frequency band. Since it is difficult to analyze mathematically 1/f-noise in the third-order system of the PLL, introducing the concept of pseudo-damping factor has made an ease of the access of the 1/f-noise variance. we showed a numerical formula of 1/f-noise variance in the third-order system of the PLL which is compared with that of 1/f-noise variance in the second-order system of the PLL

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.41-55
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• 1999

In order to evaluate the effects of knowledge, attitude and practice on noise-induced hearing loss or hearing threshold level, questionnaire survey was performed and hearing thresholds of 1 kHz and 4 kHz were measured on 1,040 subjects with workers exposed to noise, safety and health officers. industrial hygienists, analysts rind office workers. The results were as follows ; 1. The following 6 factors were obtained by factor analysis and factor rotation of 30 questionnaire of knowledge, attitude and practice about noise; knowledge of noise (F1), concern of hearing protective devices (F2), concern of noise induced hearing loss (F3), concern of noise level and hearing impairment (F4), concern of noise in workplace (F5) and recognition of noised-induced hearing loss (F6). 56.1% of variance was explained by 6 factors. 2. Significant variables influencing knowledge, attitude and practice about noise were education level and age in F1, personal protective devices (PPE) and education level in F2, age and education level in F3, education level, age and sex in F4, PPE, education level, age and work duration in F5, and work duration and PPE in F6. 3. Hearing thresholds of 4 kHz were significantly higher in workers exposed to noise than that of in the other subjects and tended to be higher in industrial hygienists, safety and health officers and analysts than that of the office workers. 4. Significant variables influencing hearing thresholds of 1 kHz were age, education level, F5 and F6 in workers exposed to noise, and F1 in industrial hygienists. 5. Significant variables influencing hearing thresholds of 4 kHz were age, F6, sex, work duration, F1, F5, F2 and F3 in workers exposed to noise, F1 and age in safety and health officers, and F6, sex and F4 in industrial hygienists. With the above results, it suggested that workers exposed to noise be needed the education of knowledge, attitude and practice about noise in hearing conservation program for the prevention of noise induced hearing loss. Also, it suggested that health managers in workplace be needed countermeasures to prevent hearing loss although they are intermittently exposed to noise.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.1
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• pp.38-42
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• 2006

We report 1/f noise PSD(Power Spectrum Density) of sub-100 nm MOSFETs as a function of various parameters such as HCS (Hot Carrier Stress), bias condition, temperature, device size and types of MOSFETs. The noise spectra of sub-100 nm devices showed Lorentzian-like noise spectra. We could check roughly the position of a dominant noise source by changing $V_{DS}$. With increasing measurement temperature, the 1/f noise PSD of 50 nm PMOS device decreases, but there is no decrease in the noise of NMOS device. RTN (Random Telegraph Noise) was measured from the device that shows clearly a Lorentzian-like noise spectrum in 1/f noise spectrum.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.653-660
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• 2001

In this paper, we designed 2303.15MHz frequency synthesizer for the purpose of the phase noise prediction. For the modeling of phase noise generated in the designed system through introducing the noise-modeling method suggested by Lascari we analyzed a variation of phase noise as according as that of offset frequency. Especially, for the third-order system of the PLL among some kinds of phase noise generated from VCO we analyzed the aspect of 1/f-noise appearing troubles in the low frequency band. Since it is difficult to analyze mathematically 1/f-noise in the third-order system of the PLL, introducing the concept of pseudo-damping factor has made an ease of the access of the 1/f-noise variance. we showed a numerical formula of 1/f-noise variance in the third-order system of the PLL which is compared with that of 1/f-noise variance in the second-order system of the PLL. As a result, In case of txco we found the reduce rapidly along the offset frequency after passed through that phase-noise was -160dBc/Hz before passed through a loop at 10kHz offset frequency and -162.6705dBc/kHz after passed through the loop, -180dBc/Hz at 100kHz offset frequency and -560dBc/kHz after passed through the loop. We can notice that the variance of third-order system more occurs (or the variance of second-order system in connection with noise bandwidth and variance factor of second-order and third-order system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.3 no.1
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• pp.18-25
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• 1978

The 1/f noise spectrum of short-circuited output drain current due to the Shockley-Read-Hal] recombination centers with a single lifetime in homogeneous nondegenerate MOS-field effcte transtors with n-type channel is calculated under the assumptions that the quasi-Fermi level for the carriers in each energy band can not be defined if we include the fluctuation for time varying quantities. and so 1/f noise is a majority carrier effect. Under these assumptions the derived 1/f noise in this paper show some essential features of the 1/f noise in MOS-field effect transistors. That is, it has no lowfrequency plateau and is proportionnal to the channel cross area A and to the driain bias voltage Vd and inversely proportional to the channel length L3 in MOS field effect transistors. This model can explain the discrepancy between the transition frequency of the noise spectrum from 1/f- response to 1/f2 and the frequency corresponding to the relaxation time related to the surface centers in p-n junction diodes. In this paper the results show that the functional form of noise spectrum is greatly influenced by the functional forms of the electron capture probability cn (E) and the relaxation time r (E) for scattering and the case of lattice scattering show to be responsible for the 4 noise in MOS fold effect transistors. So we canconclude that the source of 1/f noise is due to lattice scattering.

• Journal of IKEEE
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• v.3 no.2 s.5
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• pp.236-242
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• 1999

J noise component due to base spreading resistance ${\gamma}_{bb}$ of bipolar junction transistors fabricated by BiCMOS process is experimentally analyzed. The analysis of equivalent noise circuit for common collector shows that output 1/f noise value is purely generated from ${\gamma}_{bb}\;when\;g_m^{-1}-{\gamma}_{bb}-R_B$ is closely to zero. From the $S^{1/f}_{Irbb}=K_fI_b{^{A_1}}/f$, we fine that $A_f=2,\;K_f{\simeq}5{\times}10^{-9}$. And Hooge constant ${\alpha}$ values are in the order, of 10$^{-3}$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.8
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• pp.1713-1718
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• 2004

It has been known that 1/f noise of MOSFET is generated by the superposition of single random telelgraph signals (RTS). In this study, jitters caused by 1/f noise of MOSFET are analysed with RTS supplied to all of the nodes of the CMOS ring oscillator under investigation. Through the analysis of the variations of jitters and jitter ratios with varying values of the amplitude of RTS, it is found that the jitters and the jitter ratios are proportional to the amplitude of RTS. And the analysis of FFT of the outputs of the ring oscillator reveals that the jitters are closely related to the phase noise of the high order harmonics of the ring oscillator outputs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.606-609
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• 2003

It is known that 1/f noise of MOSFET is generated by superposition of single Random Telelgraph Signal (RTS). In this study, jitter from 1/f noise of MOSFET is analysed with RTS supplied to one of the nodes of the ring oscillator under investigation. Jitter rates are investigated as the number of stage, power supply voltage, and the amplitude of RTS change.

• Journal of Sensor Science and Technology
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• v.14 no.1
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• pp.42-46
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• 2005

It has been known that 1/f noise of MOSFET is generated by superposition of random telelgraph signals (RTS). In this study, jitters and phase noise caused by 1/f noise of MOSFET are analysed with RTS supplied to all of the nodes of the CMOS ring oscillator under investigation. Through the analysis of jitters and jitter ratios with varying values of the amplitude of RTS, it is found that the jitters and the jitter ratios are proportional to the amplitude of RTS. And the analysis of FFT of the output of the ring oscillator reveals that the jitters are closely related to the phase noise of the high order harmonics of the ring oscillator outputs.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.1
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• pp.1-6
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• 2006

High performance $Si_{0.8}Ge_{0.2}$ heterostructure metal-oxide-semiconductor field effect transistors (MOSFETs) were fabricated using well-controlled delta-doping of boron and $Si_{0.8}Ge_{0.2}$/Si heterostructure epitaxal layers grown by reduced pressure chemical vapor deposition. In this paper, we report 1/f noise characteristics of the SiGe pMOSFETs measured under various bias conditions of the gate and drain voltages changing in linear operation regions. From the noise spectral density, we found that the gate and drain voltage dependence of the noise represented same features, as usually scaled with $f^{-1}$ However, 1/f noise was found to be much lower in the device with boron delta-doped layer, by a factor of $10^{-1}_10^{-2}$ in comparison with the device fabricated without delta-doped layer. 1/f noise property of delta-doped device looks important because the device may replace bipolar transistors most commonly embedded in high-frequency oscillator circuits.