Ching-Wen Hsue

Transient analysis of nonuniform, high-pass transmission lines

The transient behavior of nonuniform transmission lines is studied by investigating the step response of a cascaded multiple-section line. The first arriving wave and the transition ripple at the load end are examined in detail. It is found that the characteristic impedances necessary for obtaining the maximum first arriving wave are the same as those of the conventional multiple-section, quarter-wave transformer. The discrete characteristic impedances of the multiple-section line are then extended to a continuously varied impedance function of a tapered line. The high-pass characteristic of the tapered nonuniform line is verified with techniques in the frequency domain. >

Built-in current sensor for I/sub DDQ/ test in CMOS

This paper presents a current sensor circuit which can be built into a CMOS logic circuit to perform a self test for leakage current. The distinct features of the current sensor circuitry are described in detail. The circuit is verified by using the SPICE2 simulator.<<ETX>>

Time-domain scattering parameters of an exponential transmission line

The scattering parameters of an exponential line are studied in detail in both the frequency and time domains. By taking the causality condition into consideration, the time-domain scattering parameters are cast in a rapid-convergence power series. Each term of the power series represents a signal component generated by the exponential line when the signal travels a round trip. The time-domain scattering parameters of an exponential line lay the foundation for studies of interaction between nonuniform lines and linear/nonlinear loads, and pulse waveform alteration in the time domain. >

Transient responses of an exponential transmission line and its applications to high-speed backdriving in in-circuit test

Step responses of an exponential line terminated with resistive loads are evaluated by means of time-domain scattering parameters. The results are used to illustrate the interaction between a nonuniform line and a nonlinear load. We find that an exponential line could be used to compensate the nonlinear load effects in high-speed backdriving. >

Elimination of ringing signals for a lossless, multiple-section transmission line

Transient processes are examined for a lossless, multiple-section transmission line terminated with resistive load. The signal components of the transmitted wave at the load end are examined in detail. The ringing effect is primarily due to two factors: (1) the voltage difference between the first arriving wave and the quasi-steady voltage and (2) the voltage signals generated by internal reflection-transmission processes which successively arrive at the output after the first arriving wave. By properly choosing the values of the characteristic impedances of the signal line it is found that a multiple-section line in which the sections are of equal length can provide high-quality signals to the load. Several examples are given to illustrate this methodology. >

Time‐domain scattering parameters for a lossy dielectric

Time domain scattering parameters of a two port are found for a ‘‘quasi‐Debye’’‐like lossy dielectric. Exact solutions are found for the zeroth‐ and round‐trip S11 parameter and the one‐way‐trip S21 parameter. Numerical examples are presented for a hypothetical material.

Clock signal distribution network for high speed testers

A high-speed clock distribution network is described. By analyzing the transient behavior of the pulse signal along a multisection transmission line, the author develops a new impedance-matching methodology to reduce the internal multireflection processes due to the impedance discontinuities in the signal line. By means of the bisection method, the matched transmission line is converted into a single-input, 2/sup n/-output, binary-tree distribution circuit. The circuit is realized on a planar printed-circuit board. Experimental results show that this distribution system can provide equiamplitude, high-fidelity, nonskewed signals to all the output terminals for pulse signal frequency in excess of 800 MHz.<<ETX>>

Transient analysis of a step wave propagating in a lossy dielectric

A transverse electromagnetic wave propagating through a lossy dielectric is studied. We propose rational functions to describe the general behavior of the permittivity as a function of frequency. The impulse response of the system is found in closed form. The step response is found in terms of a small argument series and an asymptotic expansion. Rise times may be calculated with a nominal number of terms. Pulses may be formed as the superposition of this solution.

Inverse scattering of nonuniform, symmetrical coupled lines

A novel technique is developed to reconstruct the physical layouts of nonuniform symmetric couplers from the scattering parameters at terminals. The coupler is decomposed into even- and odd-mode lines in which the decoupled modal lines are reconstructed from their respective scattering parameters. The effect of unequal modal propagation delays on the reconstructed coupler is also addressed. Numerical results are presented to illustrate the validity of this reconstruction technique.

A DC voltage is equivalent to two traveling waves on a lossless, nonuniform transmission line

A static DC voltage can be treated as two traveling waves propagating in opposite directions of a lossless, nonuniform transmission line. The amplitudes of these two traveling waves are a function of the characteristic impedance of signal line. The concept of two traveling waves is applied to a time-domain-scattering-parameter analysis in a lossless, nonuniform transmission line terminated with nonlinear loads.<<ETX>>