| 摘要 |
1,266,929. Selective signalling. WESTERN ELECTRIC CO. Inc. 14 Aug., 1969 [19 Aug., 1968], No. 40748/69. Heading G4H. In order to transmit speech digitally signals are transmitted representing the difference between actual speech samples and predicted speech samples, and the parameters utilized in making the predictions. As described input speech, Fig. 1, is filtered 10, sampled 11 and delayed 12 by 60 samples. The difference # N is then formed 13 between each sample S N and a corresponding predicted sample Z N . This difference # N is then amplified by Q, quantized S<SP>1</SP> N 15 to one of two levels, and transmitted. The quantized difference S<SP>1</SP> N is amplified by 1/Q, and added 17 to the predicted sample Z N to produce a reconstructed sample r N which, together with preceding reconstructed samples, is used 30 to predict the next sample Z N + 1 The parameters b, k and α utilized in the prediction, and the amplifier gain Q, are also transmitted. All of these parameters are computed 40 every 30 samples (5 msec.) by reference to the preceding 120 samples received direct from the samples 11-delay 12 only being present in order to provide time for this to be done. The Specification contains precise and extensive mathematical information about these parameters and illustrates methods of computing them by block diagrams. |
