| 摘要 |
1509753 Multiplex system NIPPON TELEGRAPH & TELEPHONE PUBLIC CORP 15 Oct 1975 [16 Oct 1974] 42120/75 Heading H4M In a multiplex system, wherein input speech channels are gated to produce pulse amplitude modulation signals which are digitally encoded to produce a p.c.m.t.d.m. signal for transmission, the signal after transmission being de-multiplexed in the inverse manner, there are provided analyzer, and synthesizer circuits (221-221), Fig. 1 (not shown), (321-321), Fig. 2 (not shown), which are used to parametrize the p.c.m.t.d.m. signals applied thereto in a manner dependent upon the speech characteristics, in particular to extract a partial autocorrelation coefficient defined in the Specification. It is asserted that by so parametrizing the p.c.m.t.d.m. signals a multiplex system normally adapted to handle, for example m channels, can, by use of the analyzer and synthesizer, handle a plurality, I groups each of m channels. Speech analyzer, Figs. 3, 4 (not shown).-Arrangements, utilizing memories, and channel selectors and distributers are disclosed for extracting the partial auto-correlation coefficient. Speech synthesizer, Figs. 5-9 (not shown).-Arrangements; controlled by signals (S 1 -S 3 , S 41 -S 4n ) dependent upon the speech characteristics representing the parametrization; and comprising pulse and noise generators, multipliers, digital filters, and temporary memories, operate in serial or parallel manner to reconstitute the p.c.m.t.d.m. signals for decoding to p.a.m. form and passage via low-pass filters to provide the analogue output signals. |
