This paper presents a computer modeling evaluation of the effect on mode propagation of typical perturbations in the refractive index profile produced as a result of the MCVD process. Certain profile variations were eliminated, singly and/or collectively, and the resultant changes in modal structure analyzed. The most important factor in the deterioration of the bandwidth is the presence of a refractive index dip at the core center. Small shifts in the level of dopant were seen to broaden pulse shapes and thus reduce bandwidth. Much less effect on bandwidth is associated with the ripples in the profile, as is also true for dips in refractive index below the index of the cladding near the core-cladding interface. A perpendicular rise, or step, in index of refraction at the core-cladding interface reduces the number of altered modes near the cladding.

As a major modernizing improvement data links for three important functions have been added to the 2B Electronic Switching System (ESS). The data-link system was designed with a layered architecture using an enhanced subset of the X.25 protocol. Levels 1 and 2 of the protocol are implemented in the hardware and software of a new device, the Serial Peripheral Unit Controller/Data Link (SPUC/DL). Within the SPUC/DL itself, check circuitry and software are used for error detection. A second SPUC/DL for each critical application provides redundancy on either a dedicated or dial-up basis. An elaborate diagnostic program within the 2B ESS can be invoked automatically or manually. This paper discusses some of the issues in retrofitting the BX.25 protocol to pre-X.25-speaking machines.

Assuming a particular model for “bursty” traffic at a packet-switching node, we find expressions for the expected delay of packets that are valid in light and heavy traffic. Each expression consists of a “correction factor” multiplied by the expected delay experienced by packets when the arrivals are “smooth” (Poisson) and of the same average rate. Approximate values for the correction factor in arbitrary traffic can be obtained by interpolation. This provides an example of a method that often gives fast approximate solutions for bursty traffic models that are not themselves tractable but become so when the offered traffic is assumed to be Poisson.

A mask set, incorporating a group of seven test chips, has been designed for fine-line process development and process control. Although six lithographic levels are available, the masks are generally intended to be used only in subsets of two or three levels to minimize the delay encountered in obtaining electrical test results for whichever processes require investigation. The mask levels serve a variety of purposes for special process development experiments. Available structures include: metal-oxide-semiconductor capacitors, p-n junctions, guarded and unguarded Schottky barrier diodes, ohmic contacts, van der Pauw patterns, insulated gate field-effect transistors, gated diodes, resistors for sheet resistance and linewidth variations, and tapped electromigration test strings. It is not anticipated that a process engineer should ever need more than a maximum of four levels to achieve an appropriate experimental structure for process development. It is not the purpose of these masks to establish fine-line design rules. The masks are intended to be used primarily with standard photolithographic processing, and most device structures have been designed to tolerate up to 5 μm in misalignment errors. However, certain selected features have been coded in a diminishing sequence to a minimum of 1.0 μm for special fine-line investigations. A salient feature of this mask system is the option to interleave rapid turnaround photolithographic steps with fine-line X-ray patterning; therefore, some mask levels have been reissued for X-ray lithography.

We have measured the pressure-volume-temperature relations in the high-pressure solutions used to grow electronic quartz and used this data to establish safe operating conditions for commercial production. High-temperature aqueous solution (hydrothermal) quartz growth, because of the importance of its product to electronics, must be ranked as one of the more important crystal-growth processes. We report here a convenient laboratory method for hydrothermal p-V-T measurements and give pressure data in 1.0-mol NaOH and in 1.0-mol NaOH saturated with quartz as a function of temperature up to 450° C and 30,000 psi. These results are compared with pressures measured on production-sized equipment. The results are used to establish the temperature at which the gas phase disappears under various conditions. The steels used for construction of high-pressure production autoclave equipment are brittle below a specific temperature, which increases slowly with service. Our p-V-T data can be used to assure that high pressures are avoided at temperatures where the autoclave is brittle. Finally, the depressions of pressure are used to glean information about the nature of the solute species present during growth, and can ultimately be of use in quartz rate and perfection studies.

This article describes the issues involved in operator services planning and the structure of the computer tools developed to address these issues. The approach to long-range planning of operator services networks is very flexible, and the availability of the Traffic Service Position System No. 1B further enhances this flexibility. This planning effort is a complex process that has been automated by computer tools that are both accurate and user-friendly.

The 3B20D Processor and the Duplex Multienvironment Real-Time (DMERT) Operating System provide a versatile processing base to fulfill the varied processing needs of telecommunications systems. To illustrate the versatility of the 3B20D/DMERT system, this article describes the structuring of four diverse telecommunication system applications.

This article describes the field administration facilities of the Duplex Multiple Environment Real Time (DMERT) operating system, as provided on the 3B20D Processor. These facilities are: Recent Change/Verify, the subsystem that allows manipulation of office-dependent configuration information; Field Update, the software change mechanism; and System Update, the component used to install a new generic program in an office. The article also includes information on how these capabilities fit into the overall scheme of field support in an in-service office environment.