Hearing aid device for frequency compression
With a hearing aid device suitable for executing a frequency compression, the aim is for different input signals entering the hearing aid device to be easily distinguishable even after frequency compression. To this end it is proposed that form factors should be determined from source frequency bands in which the signal components of the input signal present therein are not included in the output signal, these being included in the amplification of selected frequency bands, the signal components of which are included in the output signal.
1. A method for frequency compression of an input signal entering a hearing aid device, which comprises the steps of:
splitting a frequency range that can be transmitted by the hearing aid device into a number of frequency bands;
combining a number of adjacent frequency bands into at least one group of frequency bands;
selecting one frequency band from the group of frequency bands;
moving a selected frequency band to a target frequency band, where a signal component of the selected frequency band moved to the target frequency band being made audible to a user; and
amplifying the signal component of an input signal lying in the selected frequency band or of a signal originating from the signal component in dependence on a further signal component of a further input signal from at least one frequency band that was not selected from of the group of frequency bands.
2. The method according to claim 1 , which further comprises determining an amplification of the signal component moved from the selected frequency band to the target frequency band.
3. The method according to claim 1 , which further comprises selecting the frequency band with a greatest sound energy and/or a highest signal level within the group of frequency bands.
4. The method according to claim 1 , which further comprises multiplying the signal component lying in the selected frequency band or the signal originating from the signal component by a form factor, which is dependent on the further signal component of the further input signal from the frequency band of the group of frequency bands that is not selected.
5. The method according to claim 4 , wherein one of the following equations is included in a calculation of the form factor:
FA
=
Sum
of
the
magnitudes
of
the
signals
of
all
the
frequency
bands
of
a
group
Magnitude
of
the
signal
of
the
selected
frequency
band
;
FB
=
Sum
of
the
squares
of
the
magnitudes
of
the
signals
of
all
the
frequency
bands
of
a
group
Square
of
the
magnitude
of
the
signal
of
the
selected
frequency
band
;
FC
=
Sum
of
the
magnitudes
of
the
signals
of
all
the
frequency
bands
of
a
group
(
Number
of
frequency
bands
)
·
(
Magnitude
of
the
signal
of
the
selected
frequency
band
)
;
and
FD
=
Sum
of
the
squares
of
the
magnitudes
of
the
signals
of
all
the
frequency
bands
of
a
group
(
Number
of
frequency
bands
)
·
(
Square
of
the
magnitude
of
the
signal
of
the
selected
frequency
band
)
.
6. The method according to claim 4 , wherein the form factor influences an amplification that is significant for the selected frequency band or the target frequency band of the selected frequency band.
7. The method according to claim 4 , wherein the form factor is determined for each group of frequency bands.
8. A hearing aid device for performing a method for frequency compression of an input signal entering a hearing aid device, the hearing aid device comprising:
a filter bank for splitting a frequency range that can be transmitted by the hearing aid device into a plurality of frequency bands;
means for dividing certain frequency bands into different groups of frequency bands;
means for selecting one selected frequency band from each group of frequency bands in dependence on signal components of an input signal entering the hearing aid device in individual frequency bands of a respective group of frequency bands;
means for moving the selected frequency band to a target frequency band, where a signal component of the selected frequency band from each of the groups of frequency bands moved to the target frequency band being made audible to a user; and
means for respectively determining an amplification of the signal component of the input signal lying in the selected frequency band or of a signal originating from said signal component in dependence on a signal component of the input signal in at least one frequency band that was not selected from the group of frequency bands.