To a question about limition of capacity caused by selective systems with PSK-n-signal impact on it

The paper is dedicated to an estimation of capacity in a narrow band linear system. The expression for capacity estimation for selective systems is presented when multiposition phase shift keying signals with n discrete states impact on its input. Explicit expressions for the capacity of one and two cascaded resonant filters are obtained. Besides an equation is obtained, allowing using numerical methods to determine the capacity of the resonance filters with the number of cascades more than 2. Based on these results it was concluded that in the absence of noise or when its level is small the capacity is limited and determined by the dynamic characteristics of a selective system and the required accuracy of determination of a multiposition phase manipulated signal with n discrete states transmitted through it. Also from these results, it follows that the capacity increases insignificantly with the number of more than 32 discrete states.