| 摘要 |
1,139,017. Speech recognition. INTERNATIONAL BUSINESS MACHINES CORP. 15 Sept., 1967 [29 Sept., 1966], No. 42164/67. Heading G4R. [Also in Division H4] In a speech analysis system, a signal representative of the harmonic energy of a speech signal is obtained from the sum of rectified signals each representing a respective harmonic content of the speech signal. Speech is split by filters at 3 having passbands of width 300 hz and centre frequencies as shown, the filter outputs being rectified at 4, passed through low-pass filters (15 hz) at 25 and summed at 29 to give the total spectral energy at 32. The outputs of filters 4 are also passed to 9 where they are summed, band-pass filtered (70 hz to 150 hz viz fundamental) at 13, fullwave rectified at 14 and low-pass filtered (15 hz) at 15, to give the harmonic energy at 16 (voiced sound). The energy signals at 32, 16 are compared at 17 to produce a voiced/unvoiced binary indication at 20d, the gains of the summing amplifiers 10, 30 being appropriately chosen for this purpose. |
