Method for processing an input signal to generate an output signal, and application of said method in hearing aids and listening devices
View Patent ↗A method and a system for defining a threshold value (O max , O min , O TR ) serving to limit the output signal of a processing unit which is fed an input signal. An input-signal level is determined and the threshold value (O max , O min , O TR ) is set as a function of that input-signal level. By virtue of the fact that the threshold value is set as a function of the input-signal level, i.e. in adaptive fashion, it is also possible to limit transient noise whose level is well below the maximum value of the threshold value. As a result, when the method or system is applied in a hearing aid, the hearing comfort of the wearer of the hearing aid can be significantly enhanced.
1. A method for determining a threshold value in a hearing device, the threshold value serving to limit an output signal of a processing unit into which an input signal, s(t), has been fed, the method comprising the steps of:
determining a mean value, I, of a level of the input signal in the hearing device;
adjusting the threshold value as a function of the mean value; and
limiting the output signal in the hearing device by applying the threshold value, wherein the threshold value is adjusted independently of the output signal,
wherein the threshold value is adjusted to an upper value which is equal to the mean level of the input signal plus a preset difference, the output signal being limited by applying the upper value in case the output signal would be higher than the upper value.
2. The method of claim 1 , wherein the mean value is determined according to the following formula:
I
=
1
T
·
∫
0
T
s
(
t
)
·
ⅆ
t
wherein T represents a time interval.
3. The method of claim 1 , wherein the upper value is always less than an upper comfort level.
4. The method of claim 1 , wherein the threshold value is adjusted along a compression ratio for a hearing-impaired person.
5. Use of the method of claim 3 , for operating the hearing device for a hearing-impaired person.
6. A method for determining a threshold value in a hearing device, the threshold value serving to limit an output signal of a processing unit of into which an input signal, s(t), has been fed, the method comprising the steps of:
determining a mean value, I, of a level of the input signal in the hearing device;
adjusting the threshold value as a function of the mean value; and
limiting the output signal in the hearing device by applying the threshold value, wherein the threshold value is adjusted independently of the output signal,
wherein the threshold value is always greater than or equal to a predetermined minimum threshold value.
7. The method of claim 6 , wherein the mean value_is determined according to the following formula:
I
=
1
T
·
∫
0
T
s
(
t
)
·
ⅆ
t
wherein T represents a time interval.
8. The method of claim 6 , wherein the threshold value is adjusted along a compression ratio for a hearing-impaired person.
9. A method for determining a threshold value in a hearing device, the threshold value serving to limit an output signal of a processing unit of into which an input signal, s(t), has been fed, the method comprising the steps of:
determining a mean value, I, of a level of the input signal in the hearing device;
adjusting the threshold value as a function of the mean value; and
limiting the output signal in the hearing device by applying the threshold value, wherein the threshold value is adjusted independently of the output signal,
wherein the threshold value is adjusted to an upper value which is equal to the mean value plus a preset difference, the output signal being limited by applying the upper value in case the output signal would be higher than the upper value, and wherein the threshold value is always greater than or equal to a predetermined minimum threshold value.
10. The method of claim 9 , wherein the upper value is always less than an upper comfort level.
11. Use of the method of claim 10 , for operating the hearing device for a hearing-impaired person.
12. The method of claim 9 , wherein the mean value_is determined according to the following formula:
I
=
1
T
·
∫
0
T
s
(
t
)
·
ⅆ
t
wherein T represents a time interval.
13. The method of claim 9 , wherein the threshold value is adjusted along a compression ratio for a hearing-impaired person.