| 摘要 |
<p>PURPOSE:To shorten greatly the control time in a unit exchange mode by standardizing the frequency when the clock skew is controlled by a ring oscillator. CONSTITUTION:A control output terminal 261 of a unit 13 is connected to an input terminal 21 of an inter-device control board 10 via a coaxial cable. Thus a ring oscillator is formed for measurement of the oscillation frequency. Hereafter the same coaxial cable is used to form the ring oscillators for all logic units in a logic device, and on oscillated frequency is measured. The mean value is obtained between the maximum and the minimum measured values thus obtained and defined as the reference frequency of a logic device 19. The variable delay elements 301-306 are used for each unit and the control is carried out to obtain a frequency within an allowable range. Thus it is possible to shorten greatly the clock control time in a unit exchange mode because it is enough to perform the control so that a frequency within an allowable range is secured only to a converted unit.</p> |
