• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.215-218
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• 2003

A 2R O/E/O wavelength converter is useful for bit rate transparency, though it has a limit on cascadability due to timing-jitter accumulation. In this paper, we propose a nonlinear signal model which is more practical than the commonly used sine wave model. With our model, we theoretically analyzed the effects of timing-jitter and the cascadability of a 2R O/E/O wavelength converter. To confirm the theoretical results, we measured the cascadability in a 40-km re-circulation loop for 10 Gb/s signal.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.10 s.340
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• pp.1-8
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• 2005

This Paper Proposes the algorithm for improving the Performance or symbol timing synchronization in hoc terrestrial DTV system. The Gardner algerian is used for symbol timing synchronization has good performance in multipath fading environment but degradation of performance is caused by jitter. Though the amount of jitter becomes more little as narrow bandwidth of loop Inter, convergence speed becomes slower. This paper propose the algorithm that averages out values of loop filter every certain time and gradually reduces the bandwidth of loop filter after estimating offset using this average for the high speed of convergence and reducing the met of jitter. The proposed algorithm has better performance with high speed of convergence and the amount of jitter than conventional method.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.3
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• pp.232-239
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• 2010

By using the clock timing control at transmitter (TX), the crosstalk-induced jitter (CIJ) is compensated for in the 2-bit parallel data transmission through the coupled microstrip lines on printed circuit board (PCB). Compared to the authors' prior work, the delay block circuit is simplified by combining a delay block with a minimal number of stages and a 3-to-1 multiplexer. The delay block generates three clock signals with different delays corresponding to the channel delay of three different signal modes. The 3-to-1 multiplexer selects one of the three clock signals for TX timing depending on the signal mode. The TX is implemented by using a $0.18\;{\mu}m$ CMOS process. The measurement shows that the TX reduces the RX jitters by about 38 ps at the data rates from 2.6 Gbps to 3.8 Gbps. Compared to the authors' prior work, the amount of RX Jitter reduction increases from 28 ps to 38 ps by using the improved implementation.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1948-1951
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• 2002

In this paper, we propose a chip timing recovery algorithm that is robust to frequency offset and time variant fading environments for DS/CDMA. The proposed structure is a modified non-coherent Delay Locked Loop (DLL) that employs a decimator. Analytical expression for the proposed non-coherent DLL S-curve and steady-state timing jitter is derived and confirmed by computer simulation. The results show that the proposed structure can reduce a steady-state timing jitter of the regenerated spreading code replica to frequency offset and time-variant fading in mobile radio channel, especially in very low SNR.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.5 no.3 s.11
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• pp.13-23
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• 2006

The system using UWB is processing brisk study with Bluetooth among the wireless access that is major technology in Telematics. The low complexity and cost for realization is advantage of UWB have communication of high speed. Mamy papers have published on the timing jitter effect on system performance except for the UWB system. In this paper, we analyze the effect of timing jitter on M-ary UWB system using orthogonal Hermite pulse and perform the simulation to show symbol error rate performance. For theoretical analysis, we derive correlation function of orthogonal Hermits pulse with closed form, and as well upper bound of Symbol Error Probability for M-ary orthogonal Hermite pulse system mathematically. It is found that numerical analysis is accurate enough through simulation.

• Korean Journal of Optics and Photonics
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• v.17 no.1
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• pp.68-74
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• 2006

We have extracted an optical clock signal from a return-to-zero(RZ) pseudorandom bit sequence(PRBS) and non-return-to-zero(NRZ) PRBS data in a pulsation multi-section laser diode with DFB reflector. The ms timing jitter achieved less than 1 ps for the input 11.727 Gbit/s RZ PRBS and NRZ PRBS data. The PRE data wasconverted from the NRZ data using an NRZ to pseudo-return to zero(PRZ) converter module. The optical clock was extracted from the PRZ data which contains the clock components. Although the input PRZ data gives a timing jitter of 2 ps, the extracted clock has timing jitter of ${\~}$1 ps.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.69-76
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• 2015

In this paper, we propose and analyze a M-ary transmission scheme in time hopping ultra-wide band(UWB) system using mutually orthogonal modified Hermite polynomial(MHP) pulses. The proposed M-ary transmission scheme employs the orthogonal property between different ordered pulses and N data bits make the M-ary signals by linear combination of M MHP pluses. The theoretical analysis and simulation results show that the proposed system has better performance and higher data rate than conventional M-ary UWB system. We derive the general form of correlation function for MHP pulses and analyze bit error rate(BER) performance over additive white Gaussian noise(AWGN) with the presence of timing jitter. We show that the proposed system has the improved BER performance and robustness to timing jitter and low power spectrum density compared with conventional M-ary UWB system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.5
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• pp.369-378
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• 1988

In this paper, the performance of the timing jitter which has great effects on the echo canceller that can be used for full-duplex digital transmission on two-wire subscriber loops is analyzed. The power spectrum of timing jitter is about 8.9dB lower in the AMI input format than in the Polar-NRZ-L input format. The performance of the echo canceller also has been shown improved by 4dB when the input signal is in the AMI format.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.10
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• pp.2246-2255
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• 1997

Gardner proposed an algorithm for timing recovery of BPSK/QPSK signals based on zero-crossing detection technique. When Gardner's method is applied to multi-level PAM signals, it suffers from increased timing jitter due to self noise. To alleviate this problem, an improved algoritjm is proposed in this paper. The timing function is modified so that it zero point at the transition of PAM signals, that results in remarkable reduced timing jitter. The performance of the proposed algorithm is analyzed and compared to that of Garner's one. Finally, analytical results are verified by computer simulation.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.1
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• pp.89-101
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• 2015

This paper proposes a statistical model of 3-D positions when tracking moving targets using the uncooled infrared (IR) stereo camera system. The proposed model is derived from two errors. One is the position error which is caused by the sampling pixels in the digital image. The other is the timing jitter which results from the irregular capture-timing in the infrared cameras. The capture-timing in the IR camera is measured using the jitter meter designed in this paper, and the observed jitters are statistically modeled as Gaussian distribution. This paper derives an integrated probability distribution by combining jitter error with pixel position error. The combined error is modeled as the convolution of two error distributions. To verify the proposed statistical position error model, this paper has some experiments in tracking moving objects with IR stereo camera. The 3-D positions of object are accurately measured by the trajectory scanner, and 3-D positions are also estimated by stereo matching from IR stereo camera system. According to the experiments, the positions of moving object are estimated within the statistically reliable range which is derived by convolution of two probability models of pixel position error and timing jitter respectively. It is expected that the proposed statistical model can be applied to estimate the uncertain 3-D positions of moving objects in the diverse fields.