| 摘要 |
<p>1. Synthesis subassembly of a channel vocoder including a means (36) of reception and extraction of the data in a frame, a means (38) of producing an excitation signal, the said synthesis subassembly including : - _n synthesis channels (45) numbered from 1 to _n, each including a bandpass filter (48) and a means of energy measurement (50, 52) for measuring the energy contained in the said band, the said synthesis channels receiving on input the excitation signal coming from the means (38) of producing the excitation signal, - at least one subtractor (62) receiving on a first input the energy signal delivered by a synthesis channel and on a second input the signal coming from the means of reception (36) and representing the energy signal delivered by the corresponding analysis channel and delivering a signal expressing the signed difference between the two signals applied on input, - at least one modulator (46) associated with the subtractor, of which the input which controls the gain receives the signal delivered by the subtractor, the said synthesis subassembly being characterized in that the synthesis channels (45), the subtractor or subtractors (62) and the associated modulator or modulators (46) are arranged in cascade in this order and constitute an open loop circuit, the synthesis subassembly being arranged such that it includes at least one means of signal processing (63) including a subtractor (62) and its associated modulator (46), the said means of processing (63) including a quantification and coding circuit (56) which receives on input the energy signal from a synthesis channel (45) in order to deliver to one of the inputs of the subtractor a quantified and coded energy signal, the other input of the subtractor receiving the energy signal coming from the means of reception and delivered by the corresponding analysis channel, the modulator receiving on its signal to be modulated input the output signal from the band pass filter of the synthesis channel.</p> |
