Channel Time Delay Research Articles

Channel specific spectral properties and time delays for bimolecular collisions

The relationship between the time delay for scattering initiated in a particular state of a specific arrangement channel and densities of states is derived. Both the quantum [Eq. (66)] and classical versions [Eq. (84)] of this ’’channel specific property’’ are obtained. The resultant properties have significant import in understanding the relationship between collisional time delays and properties of the scattering system.

New Gravitational Radiation Experiments

Squared time derivatives of output powers of the Argonne and Maryland gravitational radiation detectors are written on magnetic tapes at Argonne and Maryland every 0.1 sec. A computer files the threshold crossing times. A coincidence is a pair of identical crossing times of both tapes. The accidentals rate is measured by repeating the procedure for a sequence of time delays in either channel. A significant excess of coincidences is found at zero delay.

Variable-Rate Transmission for Rayleigh Fading Channels

A modulation system is proposed that continuously adjusts its data rate in response to signal strength variations in a fading channel. The optimum variation of data rate with channel conditions is determined, and includes the effects of feedback channel time delay, the interval between rate changes, and restriction of the number of allowable rates. Application of these results to a full duplex situation allows determination of the optimum fraction of the data stream to be devoted to service information. Comparison of this scheme with diversity transmission on the basis of error probability and bandwidth utilization reveals a reduction on the order of 14 dB in transmitter power for a typical duplex link.

Decicycle magnetic amplifier systems for servo applications

The importance of minimizing time delays in a typical autopilot channel are discussed and the major advantages to be gained in the use of magnetic amplifier systems having responses which are small in comparison with the period of 1 complete cycle of the power supply are described. Magnetic frequency multipliers, magnetic pulse transformers, and transistor pulse generators are discussed, and corresponding circuit schematics which yield frequency multiplication from d-c and single-phase or multiphase a-c supplies are shown. A typical 400-cycle-per-second (cps) decicycle magnetic amplifier system which provides a reversible polarity d-c output is described. A comparison of response time, transfer characteristics, weight, and volume is made with a standard, high-performance 400-cps half-cycle response magnetic amplifier having the same power rating. It is shown that the decicycle magnetic amplifier system yields twice the sensitivity and one-sixth the response time for equivalent power rating and weight.