To obtain a separation system by which an unsteady signal is permitted so as to be handled by a method wherein a signal-source separation subassembly standardizes a first estimated value regarding a maximum estimated value expressed by a specific expression and a second estimated value which is expressed by another specific expression is generated.

A separation system processes an input signal which is formed by mixing respective primary signals generated from various signal sources, it estimates a primary signal, and it does not make its estimated value different even when an unsteady input system exists. The separation system contains a first separation subassembly which generates a firs estimated value (Expression I) for the primary signal, a second subassembly which decides a separation factor adaptively and a third subassembly which standardized the first estimated value (Expression I) and which generates a first standardized estimated value (Expression II) which is used to calculate the separation factor. An output module generates an estimated value whose ratio is identical to that which exists between primary signals. A selection module prevents the estimated value from being copied to various outputs when a primary system does not exist or when it is extremely weak.