The minimax optimization criterion for the segmented compression characteristic is formulated. For speech signal, the optimal seven segment compression characteristic is given.

This paper investigates a new method of compensating for the transmission delays encountered in communications networks employing mutual synchronization. The compensation technique suggested belongs to the category of the single-ended methods in the sense that all the phase measurements affecting the control signal supplied to the local oscillator are carried out at that particular node; however, each oscillator does get signals which reflect, to some extent, the phase relationships between the signals received and the local oscillator at all other nodes in the network. The steady-state frequency of theNnodal network is found for general phase detector characteristics in order to demonstrate the profitable properties of the returnable timing system. The effects of mismatched phase detectors and imperfect delay compensation on the network steady-state frequency is given.

Mutual synchronization between two geographically separated phase-locked oscillators is investigated for two different interconnection methods. This includes the so-called single-ended (uncompensated delay) and the double-ended (compensated delay) methods. Explicit formulas for determining the steady-state frequency and phase errors are developed for both methods. Necessary conditions for the existance of a synchronous state are derived in terms of basic system parameters. Finally, a comparison Of the methods of oscillator interconnection is made as a function of the uncompensated channel delays. Graphical results are presented which are useful in determining steadystate system performance.