Abstract :
The delay time and the group delay time are often used as measures of the delay. The former is defined as the time required for the indicial response to reach 50 percent of the final value, and can be decided quite easily if the indicial response is given. This is, however, not simply connected with the transfer function of the system or component under consideration. The latter, that is, the gradient of the phase to the angular frequency, is probably the most complete expression of the length of the delay, but is unwieldy since it is a function of the frequency. In this paper, the author defines the equivalent dead time as a new measure of the delay. This is expected to be very useful since it is simply connected with the transfer function and is not a function of the frequency.
