| 摘要 |
1532487 Automatic exchange systems INTERNATIONAL STANDARD ELECTRIC CORP 1 June 1976 [6 June 1975] 22577/76 Addition to 1483273 Heading H4K In a modification of the system of parent Specification, which discloses a TDM system wherein speech samples are switched in senal bit format via a space switching stage comprising a plurality of planes, with successive speech samples being routed in turn to successive ones of said planes, the transmission of each speech sample through a plane is controlled by clock pulses of such a frequency that the sample transmission time through the space switching stage is at least one time slot less than a number of time slots equal to the number of planes. In the prior arrangement there were four planes and the speech samples were clocked though the space switching stage at 2Ás per sample i.e. 4 system time slots. In the present embodiment five switching planes are provided but the same transmission rate of 4 system time slots is used. Hence there is a free period of one system time slot between two samples passing through the same plane and this provides adequate time for the alteration of the settings of the crosspoints of the plane. To enable speech samples relating to the same connection to always be switched by the same plane, the number of planes should be a submultiple of the number of system time slots per frame. |
