Combinational circuits testing by two diagnostic features on the base of weight-transition sum codes

It is proposed to use the properties of weight-transition sum code for organizing built-in control circuits of combinational digital devices when checking calculations by two diagnostic features. It is established that the control symbols of weight-transition sum code are described by the so-called self-quasi-dual Boolean functions that have the same values o n pairs of input combinations that differ in all variables. This property can be used in the synthesis of built-in control circuits based on Boolean signal correction. A built-in control circuit based on Boolean signal correction with verification of the belonging of the generated code words to the weight-transition sum code, as well as self-quasi-duality of each calculated function, is presented. An algorithm for obtaining the values of Boolean signal correction functions is given, which guarantees the self-quasi-duality of the functions formed in the built-in control circuit, describing the data and check symbols of the weight-transition sum code, as well as self-checkability of the built-in control circuit itself.