Data Selector Research Articles

Optimization of one-bit full adders embedded in regular structures

We study the problem of optimizing the transistor sizes in the one-bit nMOS full adder either isolated or embedded in a regular array. A local optimization method that we call the critical-path optimization method is developed. In this method, two parameters at a time are changed along the critical path until a locally optimal choice of transistor sizes is found. The critical-path optimization method uses the Berkeley VLSI tools and the hierarchical layout language ALLENDE developed at Princeton. First, we optimize the isolated one-bit full adder implemented in three ways: as a PLA, data selector, and with random logic. The details of the critical-path optimization method and power-time tradeoff curves are illustrated here. Second, we optimize the one-bit full adder embedded in a simple array multiplier. The entire 3 × 3, 4 × 4, 8 × 8, and 10 × 10 multipliers are optimized and their local optima are compared. Because the optimization of the entire circuit becomes less practical when the circuit becomes larger, we develop a method that makes use of circuit regularity. We prove that some small array of one-bit full adders, called the canonical configuration, has the same local optima as the n × n multiplier for large n, with the criterion of minimizing the delay time T. Hence, we can greatly reduce the computation load by optimizing this canonical configuration instead of optimizing the entire circuit. Experimental results confirm the effectiveness of this approach.

A multiplexer employing Josephson functional gates

A new Josephson multiplexer is designed and analyzed. Experimentally, the multiplexer is fabricated by standard Pb alloy technology with 5-µm line width, and its operation is successfully performed. The typical operating margin is ±16 percent for the gate current. The multiplexer is a four-way multiplexer with a 2-4 decoder consisting of functional AND gates. The functional gates are composed of two asymmetric logics arranged in a series on its gate current line. These gates realize 2-4 decoder and data selector functions. The multiplexer offers advantages of integrated-circuit area reduction, low power dissipation, and high-speed operation.

Circuit for time compression and expansion of audio signals

A time compression or expansion circuit for audio signals comprises an analog to digital converter (12), a random access memory (17), a latch circuit (18), a digital to analog converter (19), a clock pulse generator (13), a counter circuit (14), a data selector (16), and a timing controller (13). The timing controller (15) is supplied with a clock pulse from the clock pulse generator (13) and a timing signal from the counter circuit (18), and produces a series of writing-in pulses and a series of strobe pulses which exist alternately and have a common frequency regardless of the mode of compression or expansion or rate thereof. The analog to digital converter (12) converts an input audio signal (11) to a digital signal in response to a writing-in and reading-out switching pulse from the counter circuit (18). The random access memory (17) writes the signal from the analog to digital converter (12) in response to the writing-in pulse fed from the timing controller (15), into an address thereof designated by an address datum for writing-in, and reading a signal out of an address thereof designated by an address datum for reading-out in response to the strobe pulse of the common frequency in such a way that the written address of the memory is read multiple times or skipped being read according to the mode and rate. The latch circuit (18) holds the signal read out from the random access memory (17) in response to the strobe pulse from the timing controller (15).

Modern Electronics for Geotechnical Engineers 5. Digital Logic Circuits

Abstract Basic principles of digital electronic circuits are described. Special data selector logic principles are introduced for more complex logic operations.

Automated System For Selecting Time‐Locked Signals From Analog Recorders

ABSTRACTIn research centers where particular attention is paid to evoked potentials or event‐related slow potentials, e.g. contingent negative variation or motor potentials, the computer can facilitate the task of the researcher in distinguishing the numerous valid and non‐valid trials on a registration on‐line. A non‐valid trial is one that has been contaminated by artifacts such as eyeblinks, eye‐movements, etc. Many of them, however, still use magnetic tape for data storage for off‐line analysis. Simultaneous with the visual control of the EEG the valid trials are selected and then averaged by means of a special purpose computer (averager) I. These analyses are time‐consuming and quite fatiguing because in case of a heavily contaminated registration, one must stop and restart the averager continuously: for this reason tape speed is limited for off‐line analysis. This paper describes a system. Automatic Data Selector (A.D.S.), which can be programmed and then automatically selects the valid trials. See Fig. 1.

Logical phase-controlled oscillator

The output from a data selector driven by a polyphase binary oscillator and addressed by a digital counter enables the sum or difference of two frequencies to be selected.

Digital Data Processing of Oilfield Production Data

Abstract This paper is primarily concerned with relating time-proven digital data-processing techniques with a modern-day automatic lease production-control system. The system described is one recently installed in southeastern New Mexico. It is comprised of three remote batteries involving 150 producing wells (both flowing and pumping), 7 LACT units, 8 separate pay zones and 77 alarms, located 20 to 30 miles away from the central office. The connecting link between the central office and the three remote batteries is a leased two-wire telephone system. Several supervisory control functions are handled with this system in addition to transmitting and recording production data, e.g., individual-well test data, LACT data, tank gauge readings, various alarm conditions and other pertinent information. Application of Communications Equipment for Digital Data Processing Extensive use of communications equipment is providing oil producers with an efficient means for handling production data. Manufacturers are offering equipment with higher reliability, greater flexibility and lower over-all cost, which affords the application of such equipment for operation of lease systems. Frequency-shift tone equipment was selected as the communications medium for the system described in this paper. In this method of tone transmission a non-keyed or non-information condition represents a "space", or low-frequency tone, while an information pulse keys the transmitter to a "mark", or high-frequency tone. Either a "space" or "mark" signal is present on the transmission line at all times. Lack of either condition or a "no carrier" signal provides a fail-safe supervisory control function which causes the remote batteries to switch into "local control". The "no carrier" condition is indicated in the central office as an "error transmit" signal. Supervisory control or interrogation data are transmitted over the two-wire telephone system from the central office to the remote batteries by the use of a basic sequential-pulse-code system, wherein each control function is assigned a particular pulse-code arrangement. A "remote data selector" with selection of automatic or manual operation generates the DC-pulse code bits to key the frequency-shift tone transmitter for transmission of the proper supervisory control function. The frequency-shift receiving equipment at each remote location has matching frequencies to correspond with the transmitter frequency at the central office. Telemetering information or information on the measurement of quantitative variables is transmitted from each of the three remote batteries to the central office using tone transmitters of identical frequencies to match the receiving frequency of the frequency-shift tone receiver located in the central office. The telemetered data arrive in the central office in the form of an eight-channel coded paper tape. The ability to transmit the standard eight-channel code over a single tone channel is made possible by use of an eight-channel tape transmission machine which sends each bit of the eight-bit binary code in a determined sequence. In addition to regular tape transmission, this machine also has the ability to read and punch paper tapes. The supervisory control system of the communications link is so designed that a transmission failure at any one of the remote batteries, at the central office or of the actual two-wire line causes the batteries to switch into "local control". This feature provides a tremendous advantage for a data-processing system of this description, in that information is retained at the battery in the event of equipment or line failure of the communication link. Operation of Field Installations A system utilizing the equipment just described has recently been installed in Lea County, N. M. The system is made up of one central control and recording point located in Hobbs, N. M., with information telemetered from the separate battery installations located from 20 to 30 miles away. The batteries have different characteristics and, for purposes of description, will be referred to as Batteries A, B and C. Battery A Battery A is comprised of 106 producing wells, some flowing and some pumping, divided among nine different leases. JPT P. 1191^