Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
294 words
A signal processing system for converting a speech signal into a data signal for controlling a hearing prosthesis including an implanted electrode array adapted to stimulate the auditory nerve fibres of a patient by the application of electrical currents to selected electrodes in said array, said processing system comprising means (20,21) for generating an input signal corresponding to a received speech signal, means (30-36) for estimating the amplitude and frequency of the fundamental voicing component of said speech signal, means (22-26, 27, 28; 49-52; 55 to 59 and 62 to 66) for estimating the amplitude and frequency of at least one formant of said speech signal, programmable means (40) for producing instruction data which in use causes the application of said electrical currents to selected groups of electrodes in said array with or without delays between the stimulation of each electrode in said groups, said programmable means being programmable with data (Figure 4) defining a predetermined relationship between each group of electrodes and a selected range of at least one formant frequency and with data defining a predetermined relationship between another formant frequency and the delay between stimulation of each electrode in each said group based on psychophysical testing of the patient and causing selection of said electrodes based on the estimated frequency of said formants such as to produce the desired percepts in the auditory-like sensations generated in the patient, said programmable means (40) further being programmable to produce data which determines the level of stimulation of each selected -group of electrodes and determines the delay between stimulation of electrodes in each said group dependent on said estimated amplitude of said formants of said speech signal as well as on predetermined data relating to the sensitivity of each electrode implanted in the patient.
Claim 2
Dependent Claim
294 words
A signal processing system for converting a speech signal into a data signal for controlling a hearing prosthesis including an implanted electrode array adapted to stimulate the auditory nerve fibres of a patient by the application of electrical currents to selected electrodes in said array, said processing system comprising means (20,21) for generating an input signal corresponding to a received speech signal, means (30-36) for estimating the amplitude and frequency of the fundamental voicing component of said speech signal, means (22-26, 27, 28; 49-52; 55 to 59 and 62 to 66) for estimating the amplitude and frequency of at least one formant of said speech signal, programmable means (40) for producing instruction data which in use causes the application of said electrical currents to selected groups of electrodes in said array with or without delays between the stimulation of each electrode in said groups, said programmable means being programmable with data (Figure 4) defining a predetermined relationship between each group of electrodes and a selected range of at least one formant frequency and with data defining a predetermined relationship between another formant frequency and the delay between stimulation of each electrode in each said group based on psychophysical testing of the patient and causing selection of said electrodes based on the estimated frequency of said formants such as to produce the desired percepts in the auditory-like sensations generated in the patient, said programmable means (40) further being programmable to produce data which determines the level of stimulation of each selected -group of electrodes and determines the delay between stimulation of electrodes in each said group dependent on said estimated amplitude of said formants of said speech signal as well as on predetermined data relating to the sensitivity of each electrode implanted in the patient.
Claim 3
Dependent Claim
55 words
A signal processing system as claimed in claim 1 which includes means (37) for determining whether said speech signal is voiced or unvoiced and said programmable means is programmed to provide instructional data to the means (44) for stimulating electrodes, so that a lower substantially constant frequency is generated in response to unvoiced speech signals.
Claim 4
Dependent Claim
91 words
A signal processing system as claimed in claim 1 or claim 2 wherein the programmable means (40) is programmed to provide instructional data to the means (44) for stimulating the electrodes such that the stimulation of electrode pairs is at a rate proportional to the fundamental voicing component, and the stimulation of selected pairs of electrodes with varying current amplitudes is used to represent the frequency of a second speech formant and the delay between the stimulation of electrode pairs is used to represent the frequency of the first speech formant.
Claim 5
Dependent Claim
90 words
A signal processing system as claimed in claim 1 or claim 2 wherein the programmable means (40) is programmed to provide instructional data to the means (44) for stimulating the electrodes such that the stimulation of electrode pairs is at a rate proportional to the fundamental voicing component and the stimulation of particular electrode pairs is used so that the stimulation of one electrode in a pair represents a frequency of the first speech formant and the stimulation of the second electrode represents the frequency of the second speech formant.
Claim 6
Dependent Claim
46 words
A signal processing system as claimed in any preceding claim, in which the programmable means (40) in response to one received signal stimulates one electrode with a predetermined amplitude and then within 0.2 to 5 milliseconds later stimulates a second electrode with a second predetermined amplitude.
Claim 7
Dependent Claim
77 words
A signal processing system as claimed in claim 1 of WO 80/02767 wherein the means for generating an input signal corresponding to a received speech signal generates a signal having a plurality of formant components and wherein means are provided for estimating the amplitude and frequency of pairs of formant components and wherein the programmable means is able to produce instruction data to cause application of electric current to pairs of electrodes for any one received signal.
Claim 8
Dependent Claim
45 words
A signal processing system as claimed in claim 6, wherein the electric current applied to pairs of electrodes is either supplied simultaneously to said electrodes or else separated by an interval which is small in relation to the average delay between the input signals themselves.
Claim 9
Dependent Claim
27 words
A signal processing system as claimed in claim 6 or claim 7 in which the means for sensing whether a signal is voiced or unvoiced is omitted.
Claim 10
Dependent Claim
38 words
A signal processing system as claimed in claim 1 of WO 80/02767 which has been modified by adding means to accommodate at least one additional digital word input and means to stimulate two electrodes from one received signal.