Y.G. Zayko - Ph.D. (Eng.), Associate Professor, Subdepartment Director, JSC «NII «Argon». E-mail: argon@argon.ru
L.N. Iskandarova - Engineer-Programmer, JSC «NII «Argon»

There are options for building highly reliable systems of radioelectronic equipment with the separate loaded backup considered in the article. For widely used systems with the independent separate backup there are given the formulas for calculating the probability of failure-free operation in the general case where a redundant system consists of «m» serially connected reserved groups each of which consists of one basic module and the (n-1) modules of always-on backup. There are systems with a dependent separate backup where control module controls a particular part of the reserved working modules and where the rejection of control module disables all this part of the working modules considered in more detail. These considered systems generally consist of «n» control modules and «m» serially connected groups each of which represents loaded backup of the «n» working modules. Conventionally, such a system can be divided into «n» channels, each of which consists of one control module and «m» working modules. Failure of one of the control modules leads to failure of the corresponding channel. Each of the «m» of serially connected groups have the multiplicity «1 of n», i.e. for the normal functioning of the redundant connections it is enough to have at least one functioning working module in the group. For the systems with dependent separate backup, there is derived the formula for calculating the probability of failure-free operation in the general case, where the failure rate of each module in the system are different. Due to the complexity of such a formula in a general way there is given an algorithm for computing the probability of failure-free operation for a redundant system with independent separate backup.