摘要:

For some applications, such as aircraft control, military communciations etc., we should have a larger mean time to failure (MTTF). This is whyN-modular redundancy (NMR) [1] is used instead of triple modular redundancy (TMR) [2] to increase the MTTF. However, the reliability of the fault-tolerance system decreases as the faulty modules increase. The reconfiguration 5MR [3] can improve this problem. It can tolerate up to three faulty modules in a 5MR system. But forN> 5, the design is more difficult and accordingly the hardware becomes more complicated. In the paper we introduce a general version of the reconfiguration NMR (GVRNMR) system. Not only does it simplify the design process, but it also decreases the hardware complexity.

DOI:10.1049/ip-g-2.1990.0001

出版商:IEE    

年代:1990

数据来源: IET

摘要:

An improved DC parameter-extraction methodology for bipolar transistors is presented. The method uses a new step-by-step strategy based on measurements made under two saturation conditions only: zero voltage and zero current. This method minimises the self-heating effects without using pulsed techniques, and it is suitable for medium-power devices. Special emphasis has been placed on the determination of resistive parameters. The proposed method fits better the experimental data than the parameterextraction methodologies in use today. The relative r.m.s. error decreases from a value higher than 10% to 1% at high current levels.

DOI:10.1049/ip-g-2.1990.0002

出版商:IEE    

年代:1990

数据来源: IET

摘要:

It is shown that the performance of anRC-active oscillator proposed by Reddy is sensitive to loop-gain errors and that designs based on minimising excess phase shifts are less than optimum. A modified design which reduces the frequency sensitivity to uniform gain-bandwidth product variations to near zero is presented, together with analytical support and experimental details.

DOI:10.1049/ip-g-2.1990.0003

出版商:IEE    

年代:1990

数据来源: IET

摘要:

In the paper, the problem of computer formulation of circuit equations using the modified nodal analysis, especially in microcomputers, is addressed. The modified nodal formulation gives rise to a disproportionately large number of circuit equations even for small-size networks. An algorithm is presented to reduce the circuit equations to a very small number before solving them repeatedly, as in the case of obtaining frequency and/or time-domain responses. This reduces the memory requirement as well as run time for the solution of network responses. Though this is useful in any computer-aided analysis of networks, it is especially useful in microcomputers where these two facts are significantly important. This also eliminates the need for solving the circuit equations using sparse matrix techniques.

DOI:10.1049/ip-g-2.1990.0004

出版商:IEE    

年代:1990

数据来源: IET

摘要:

We review the main difficulties and advantages in developing CMOS ternary circuits. In addition to employing multiple power sources and multiple thresholds, we describe a new theory of transmission functions for designing CMOS ternary logic circuits. It can explain the main CMOS ternary circuits proposed previously. Computer simulations show that the circuits based on the transmission-function theory have more desirable transfer characteristics than ones with resistors.

DOI:10.1049/ip-g-2.1990.0005

出版商:IEE    

年代:1990

数据来源: IET

摘要:

A method for implementing flip-flops using a folded PLA in a feedback connection is proposed. The new approach is shown to give effective circuits in terms of silicon area.

DOI:10.1049/ip-g-2.1990.0006

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The intrinsic low-field mobility μoand the mobility surface-degradation constants Θoand ΘBin varying channel lengthpMOS transistors at cryogenic temperatures are presented. It was found that μoincreased from 180 cm2/V s at 300 K to 1260 cm2/V s at 77 K, and that Θoalso increased with 0.10 at 300 K to 0.49 at 77 K. These two parameters were extracted using an analytical model for thepMOS devices in its ohmic mode of operation that is very suitable for use in circuit simulation programs such as SPICE.

DOI:10.1049/ip-g-2.1990.0007

出版商:IEE    

年代:1990

数据来源: IET

摘要:

Mathematical simulation and experimental studies of an MINpn(MISSS) metalconducting insulator-semiconductor bipolar transistor are described in the paper. Such devices generally have switching characteristics. The high-impedance state is associated with a reversebiasedp-njunction which sustains high voltages. The breakover occurs when the sum of the small-signal current gains reaches unity. The low-impedance state is associated with an accumulation of the semiconductor surface which increases the electric field across the insulator. The energy bandshift may cause the valence-band edge of the semiconductor to be at a higher energy level than the metal-work function. The metal-insulator-semiconductor (MIS) acts as a minority diode and has a large flow of valence electrons. The second regenerative feedback may create the intermediate stable state, if the positive resistance appears prior to the second breakover. The simulation results show that this intermediate stable state may happen when the oxide thickness is within a certain (tunnelling) range. The larger barrier height device (majority diode) has a greater possibility of exhibiting the intermediate stable state. The narrower basewidth device is more significant in indicating the voltage collapse. The experimental result confirmed the existence of the intermediate stable state.

DOI:10.1049/ip-g-2.1990.0008

出版商:IEE    

年代:1990

数据来源: IET

摘要:

Precision phase shifters for processing sinusoidal signals are described. The proposed circuits are capable of extremely low phase errors and in the case of a 120° design could, for example, maintain a phase constancy of ±0.015 degrees in the face of variations in frequency of ±5% about the central design value. The effects of limited amplifier bandwidth on the phase responses are examined and alternative design strategies with reduced gain bandwidth dependence are suggested. An economical quadrature phase shifting network is also presented, together with a simple phase-error compensation arrangement.

DOI:10.1049/ip-g-2.1990.0009

出版商:IEE    

年代:1990

数据来源: IET

摘要:

In the paper, the reduced modified nodal approach (RMNA) and reduced nodal approach with nullors (RNAN) are used to formulate generalised state equations and multiport hybrid equations. This approach can be used to improve generalised programs, such as SPICE and ECAP.

DOI:10.1049/ip-g-2.1990.0010

出版商:IEE    

年代:1990

数据来源: IET