Speech processor using contiguous multiband center-clipping

Claim 2

Apparatus for processing speech signals in a telephonic voice communications channel containing reverberant speech energy, comprising: a first bank of filters disposed in the path of transmission and being substantially contiguous in band and occupying a frequency range substantially the bandwidth of said channel; means for individually center clipping the outputs of the respective filters within a region substantially embracing the peak amplitudes of said reverberant speech energy; means for continuously summing the outputs of said centerclipping means; and means for transmitting the resulting sum to a user point.

Claim 3

Apparatus in accordance with claim 1 further comprising a second bank of filters connected to respective ones of the center-clipper outputs, the band of each said filter having frequencies common with the band of the filter on the input side of the respective center clipper.

Claim 4

Apparatus in accordance with claim 2, wherein the passband widths of the respective filters in said second bank are substantially congruent to the passband widths of the filters in said first bank.

Claim 5

Apparatus in accordance with claim 3, wherein the filter passbands of said first bank are substantially two-thirds octave wide.

Claim 6

Apparatus in accordance with claim 2, further comprising means for delaying the output of each filter in said first bank sufficiently to render the response peaks of all substantially time-coincident.

Claim 7

Apparatus in accordance with claim 5, wherein the transfer function of each said center-clipping means is in accordance with that depicted in FIG. 3.

Claim 8

In a a telephonic-voice-communications link including a station at which speech is originated in a reverberative enclosure, apparatus for reducing the transmitted reverberative energy comprising: a first bank of filters connected in the transmission path of said station, the filters being substantially contiguous in band and occupying a frequency range corresponding to the bandwidth of said link; means for center clipping each of the outputs of the respective filters within a region substantially embracing the peak amplitudes of said reverberative energy; means for continuously summing the outputs of said center-clipping means, and means for transmitting the resultant sum over said link to a remote station.

Claim 9

In a a telephonic-voice-communications link including a station at which speech is originated in a reverberative enclosure, apparatus for reducing the transmitted reverberative energy comprising: a first bank of filters connected in the transmission path of said station, the filters being substantially contiguous in band and occupying a frequency range corresponding to the bandwidth of said link; means for center clipping each of the outputs of the respective filters within a region substantially embracing the peak amplitudes of said reverberative energy; means for continuously summing the outputs of said center-clipping means, and means for transmitting the resultant sum over said link to a remote station.

Claim 10

Apparatus in accordance with claim 7, further comprising a second bank of filters, each connected to respective ones of the center-clipper outputs for removing clipping-distortion products which fall outside of the passband of the corresponding first filter.

Claim 11

Apparatus in accordance with claim 8, wherein the passband widths of the respective filters in said second bank are congruent to the passband widths of the filters in said first bank.

Claim 12

Apparatus in accordance with claim 9, wherein the filter passbands of said first bank are substantially two-thirds octave wide.

Claim 13

Apparatus in accordance with claim 8, further comprising means for delaying the output of each filter in said first bank sufficiently to render the response peaks of all substantially time-coincident.

Claim 14

Apparatus in accordance with claim 11, wherein the transfer function of each said center-clipping means is in accordance with that depicted in FIG. 3.

Claim 15

In a telephone voice communications link between relatively remote stations and including an electrical circuit echo characteristic, apparatus for reducing the power level of said echo, comprising: a first bank of filters disposed in the path of transmission and being substantially contiguous in band and occupying a frequency range substantially the bandwidth of said channel; means for individually center clipping the outputs of the respective filters within a region substantially embracing the peak amplitudes of said echo; means for continuously summing the outputs of said center-clipping means; and means for transmitting the resulting sum to a user point.

Claim 16

In a telephone voice communications link between relatively remote stations and including an electrical circuit echo characteristic, apparatus for reducing the power level of said echo, comprising: a first bank of filters disposed in the path of transmission and being substantially contiguous in band and occupying a frequency range substantially the bandwidth of said channel; means for individually center clipping the outputs of the respective filters within a region substantially embracing the peak amplitudes of said echo; means for continuously summing the outputs of said center-clipping means; and means for transmitting the resulting sum to a user point.

Claim 17

ApparAtus in accordance with claim 13, further comprising a second bank of filters, each connected to respective ones of the center-clipper outputs for removing clipping-distortion products which fall outside of the passband of the corresponding first filter.

Claim 18

Apparatus for processing speech signals in a telephone voice communications channel containing reverberant or circuit-echo-speech energy, comprising a first bank of filters disposed in the path of transmission and having passbands substantially two-thirds octave wide beginning at a low-pass point of approximately 250 Hz.; means for delaying the output of each filter in said first bank sufficiently to render the response peaks of all substantially time-coincident; means for individually center clipping the outputs of the respective filters at a point about one-tenth the level of average peak amplitude exhibited in the respective band; a second bank of filters, each connected to a respective one of the center-clipper outputs, and having passbands substantially congruent to the filters of said first filter bank; means for continuously summing the outputs of said second bank of filters; and means for transmitting the resulting sum to a user point.

Claim 19

Apparatus for processing speech signals in a telephone voice communications channel containing reverberant or circuit-echo-speech energy, comprising a first bank of filters disposed in the path of transmission and having passbands substantially two-thirds octave wide beginning at a low-pass point of approximately 250 Hz.; means for delaying the output of each filter in said first bank sufficiently to render the response peaks of all substantially time-coincident; means for individually center clipping the outputs of the respective filters at a point about one-tenth the level of average peak amplitude exhibited in the respective band; a second bank of filters, each connected to a respective one of the center-clipper outputs, and having passbands substantially congruent to the filters of said first filter bank; means for continuously summing the outputs of said second bank of filters; and means for transmitting the resulting sum to a user point.