Measurement Of Propagation Delay Research Articles

Comparison of microelectronic test structures for propagation delay measurements

Propagation delay is a parameter which needs to be accurately measured for characterization of VLSI fabrication technologies and VLSI circuit design. In this experiment, three different microelectronic test structures or test circuits were used to measure the propagation delay of a minimally sized CMOS inverter. The measured results and a comparison of the test circuits are presented.

Direct measurement of picosecond propagation delays in individual logic gates by a differential optoelectronic technique

We describe the first direct measurement of single-gate propagation delays in gigabit GaAs digital IC's. Our technique uses picosecond light pulses to generate short on-chip logic-level-switched pulses and infers single logic gate delays by differential measurement of output waveforms. In the ∼ 2-GHz clock-rate D-flip-flop selected for these measurements, single-gate propagation delays of ∼ 100 ps were measured in specific NOR gates internal to the flip-flop (FF) with this new measurement technique; the technique is easily extendible to measurement of gate delays of the order of a few picoseconds.

A new technique for the measurement of speeds of gigahertz digital IC's

We describe a new technique for the measurement of picosecond switching speeds and propagation delays in gigahertz digital IC's. This technique, based on logic-level sampling with pairs of ultrashort optical pulses at variable interpulse delays, provides accurate and reliable values of picosecond propagation delays without requiring the coupling of high-frequency electrical signals to and from the IC chip. Since this optical technique dispenses with the usual need for dicing and mounting the IC wafer in high-frequency (multigigahertz bandwidth) test fixtures, a promising application of its use is in the precise temporal characterization of multigigabit logic circuits in low-frequency (< 100-MHz) probe stations.

Test structures for propagation delay measurements on high-speed integrated circuits

The accuracy of high-speed wafer-level measurements on digital IC's is limited by the probe interface. This limitation strongly encourages the use of built-in on-chip test hardware to reduce the number of critical off-chip high-speed interfaces. A novel synchronous propagation delay test structure is described which will provide accurate parametric data under typical automatic test conditions. Built-in test features added to complex combinational circuits are shown which are useful for delay measurement and which reduce the total number of high-speed I/O connections while still providing acceptable fault coverage in many cases.

Fiber-dispersion and propagation-delay measurements with frequency-and amplitude-modulated cleaved-coupled-cavity semiconductor lasers

By using combined frequency and amplitude modulation of a cleaved-coupled-cavity semiconductor laser together with a phase-sensitive detection scheme, we have measured the chromatic dispersion in a single-mode silica fiber. The method presented can measure dispersion down to 0.03 psec/nm km and, with a slight modification to the measurement routine, also measure the total propagation time with a 10(-7) accuracy.

A PCM‐TDMA one dimensional mobile communication system using leaky coaxial cables

AbstractIn TDMA mobile communication systems, synchronization between a base station and mobile stations is a primary problem. This paper proposes a new mobile station synchronization scheme which does not require the propagation delay measurement or very long guard time for a one‐dimensional mobile communication system using leaky coaxial cables (LCX). It shows that a large‐capacity PCM‐TDMA mobile communication system can be realized based on the proposed synchronization scheme, and describes an application method for the train mobile communication system. Mobile station synchronization scheme, signal transmission system, and synchronization scheme between base stations are described. On the estimation of the attainable bit rate from the physical environment of the transmission paths, the required guard time length and the optimum burst length are determined, and the frame structure and the channel control method are described. to demonstrate the feasibility of the system, a signal transmission experiment using an LCX at the estimated maximum bit rate has been carried out and the possibility of high‐speed pulse transmission by means of LCX has been confirmed.

Total Dose Effects on Circuit Speed Measurements

Measurements of propagation delay as a function of total ionizing dose were made using ring-oscillators, inverter chains, and NAND chains fabricated on the same CMOS test chip. The data illustrate the impact of the bias conditions of the MOS transistors during irradiation on the propagation delay time of the circuits. The data show no difference in propagation delay time for the three circuit types if comparable bias conditions are maintained during radiation exposure. The threshold voltage shift of the n-channel transistors appears to be the dominant factor controlling the decrease in propagation delay as the total dose increased. The ultimate failure of the test circuits is due to the shift of the n-channel transistors to a negative threshold voltage.

Measurement of relative propagation delay between C- and K-band satellite loops

Variations of relative propagation delay between <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</tex> - and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</tex> band satellite loops were measured using a communication satellite. This measurement employed a frequency modulation (FM) and a time division multiple access (TDMA) method. The maximum observed delay change was about 6 ns during the ten-day experimental period. The experimental results show that the delay variations are caused mainly by variations of the total electron content in the ionosphere, and also, a small change of about 0.2 ns due to the spin motion of the satellite is found.