| 摘要 |
1528240 Conference circuits SOC ITALIANA TELECOMUNICAZIONI SIEMENS SpA 2 Aug 1976 [31 July 1975] 32050/76 Heading H4K In a conference circuit compressed P.C.M. codes are numerically combined in compressed form. In one embodiment described codes from three subscribers and each comprising a base (mantissa) and a segment number (compression factor or exponent plus a sign bit) are stored in an input unit (Fig. 3, not shown), forwarded in pairs to a preprocessing unit (Fig. 4, not shown) having two pairs of stores for the bases and segment numbers and arranged to shift the digits (bits) of the base of one code of each pair to the right or left through a number of digit positions equal to the difference between the segment numbers of that pair of codes and calculated by a first processing unit (Fig. 5, not shown), then further forwarded to a second processing unit (Fig. 6, not shown) which adds or subtracts in accordance with the sign bits the two bases of each pair to generate sum or difference codes. A four subscriber conference system (Fig. 9, not shown) is described. Six time channels are utilized. Codes from subscribers A and B are added to form partial sums which are combined with codes from subscribers C and D using three channels in a manner similar to a three party conference to provide B+C+D and A+C+D and codes from C and D are added to form partial sums C + D which are combined with codes from A and B to give A+B+D and A+B+C. |
