THE METHOD OF SYNTHESIS OF SPECIALIZED DIGITAL DEVICES FOR FORMING THE SEQUENCE OF PULSES WITH SPECIFIED PARAMETERS
The work is devoted to the method of designing digital devices for the formation of a periodic sequence with predetermined pulse and pause durations. These durations are chosen multiples of the period of clock pulses according to the regularity 2i. This feature allows you to obtain compact schemes of functional nodes and reduce the complexity of the device. A method for designing specialized digital devices is proposed, which takes into account the periodicity of the output data. It is based on the representation of logical triggering switching functions in a generalized form. This form allows you to simplify the procedure for analyzing and synthesizing digital devices. The method includes the stage of decomposition of the final graph of the change of working states into independent branches with a given sequence of state changes in the branches, which makes it possible to define the operating part of the device as a ring machine. At the stage of structural synthesis the projected device is represented in the form of a functional-block composition of several interrelated individual blocks. Each block is a finite state machine, which allows you to specify the series of pulses with your start addresses and the lengths of the series. The use of a typical flip-flop with the count input, which forms the value of the signal at the output, made it possible to abandon the combination circuit for generating the output signal. This design feature has made it possible to reduce the complexity of the specialized pulse shaping device, in general, and to reduce the delay. The functions of transition of all memory elements to the initial (zero) state when the power supply is switched on are assigned to the start-stop device. It is performed on a typical asynchronous RS-flip-flop with direct inputs R and S. Practical value of the method consists in combining the functioning of synchronous and asynchronous triggers, their direct and inverse inputs for different modes. Such a combination in practical implementation makes it possible to reduce transients.