Decoding circuit and information processing apparatus

A decoding circuit for estimating a maximum likelihood sequence through the effect of the Viterbi algorithm by using a survivor path sequence storing circuit for storing a desired number of decoding input signal sequences, comprising:

• said survivor path sequence storing circuit having the features of;
• (a) D storing circuit blocks (D is an integer) having as component elements N selecting circuits and N or more storing circuits, said N selecting circuits for being inputted with N (N is an integer) survivor path sequence selecting signals composed of a given number of signal lines from a path metric operating and comparing circuit at each operating unit time of a decoding process and selectively outputting a signal at one of plural input terminals with each of said survivor path sequence selecting signals as a selection indicating input signal, and said N or more storing circuits for being inputted with each selecting output signal from said selecting circuits or a signal of an individual input terminal and holding said signal at each operating unit time, an output signal for a content stored in said storing circuit being connected with a given one of said input terminals so that the selected stored content of said storing circuit is made to be the stored content of said given storing circuit at each operating unit time,
• (b) a starting signal generating circuit for generating a starting signal at said operating unit time and cyclically supplying said starting signal to any one of said D storing circuit blocks sequentially in a given sequence, said starting signal generating circuit serving to inevitably supply said starting signal to one of said storing circuit blocks at each of said operating unit times during a decoding period and periodically supply said starting signal to said storing circuit block being inputted with said starting signal at given operating unit time intervals, and
• (c) in said (b), said storing circuit block being inputted with said starting signal having a function of outputting as a decoded result a stored content of a given one of said storing circuits composing said block, and at once setting all the stored contents of said storing circuits to a given initial value.

A decoding circuit for estimating a maximum likelihood sequence through the effect of the Viterbi algorithm by using a survivor path sequence storing circuit for storing a desired number of decoding input signal sequences, comprising:

• a plurality of storing means composing said survivor path sequence storing circuit and divided into plural storing circuit blocks;
• each of said storing circuit blocks having a common selection input signal and a discrete detected output signal, wherein the survivor path sequence storing circuit comprises:
• a coincidence detecting circuit for referring to a stored content of a given number of storing circuits contained in said storing circuit block for detecting if said stored contents are coincidental with each other, and
• a function of breaking supply of a synchronous clock signal to part or all of said storing circuits composing said storing circuit blocks or stopping an operation of updating said stored content at each operating unit time in response to an output of “the stored contents are coincidental with each other” from said coincidence detecting circuit.