Digital machine.
We call the digital automaton (CA) every artificial system of processing information in digital form. Such a device has input and output. They used a parallel presentation of information, and the CA for processing sequential information serves as a special case. The set of input and output signals of CA at any given time are called respectively the input and output word. The work of any CA can be interpreted as a transformation of the input words into output words of the same or a different alphabet. By alphabet understand the set of all symbols used. Input and output words can be changed only at certain times, called the clock. It is convenient to denote the nonnegative integers.
/ = 0, 1, 2, ... , / ...
The time interval between two adjacent clock moments called tact. Duration of cycles may be uneven, but in most cases they are of equal and are determined by the generator synchronization.
At first glance, like the CA vocabulary that every word in correspondence with foreign-language equivalent. But in order to remind the interpreter must take into account that the meaning of words, usually in close connection with the preceding text, so in general, the CA must be able to store incoming data in a. However, in contrast to an interpreter in some cases, the CA is not enough to remember the word, but the fact of its appearance, that allows saving memory.
How to describe the operation of CA.
Thus, the CA under the influence of the input word changes from one state to another, keeping the adopted state, at least during the stroke, and in the general case, the output word depends not only on the input signal, but also on the state and the first mate.
Any digital machine can be constructed from two types of devices - combinational circuits (CC) and schemes with memory, which can themselves be regarded as elementary CA.
The structure and operation of any CA is closely associated with the presentation of information. If all the input information can be presented in parallel, in the form of one word, memorizing it is necessary only in cases where the elements of CA are not designed to handle long words. In all other cases the CA may be in the form of a COP, and its performance will be maximized.
With consistent form of presentation inevitably its memorization. For this reason, the memory circuit is sometimes called sequential.