Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03G—CONTROL OF AMPLIFICATION
  • H03G5/00—Tone control or bandwidth control in amplifiers
  • H03G5/16—Automatic control
  • H03G5/18—Automatic control in untuned amplifiers
  • H03G5/22—Automatic control in untuned amplifiers having semiconductor devices
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03G—CONTROL OF AMPLIFICATION
  • H03G9/00—Combinations of two or more types of control, e.g. gain control and tone control
  • H03G9/02—Combinations of two or more types of control, e.g. gain control and tone control in untuned amplifiers
  • H03G9/025—Combinations of two or more types of control, e.g. gain control and tone control in untuned amplifiers frequency-dependent volume compression or expansion, e.g. multiple-band systems
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R25/00—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception
  • H04R25/35—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception using translation techniques
  • H04R25/356—Amplitude, e.g. amplitude shift or compression
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R25/00—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception
  • H04R25/50—Customised settings for obtaining desired overall acoustical characteristics
  • H04R25/502—Customised settings for obtaining desired overall acoustical characteristics using analog signal processing

Definitions

• the invention relates to a hearing instrument comprising a circuit for transforming an audio signal into an output signal, which circuit comprises filter means for dividing the audio signal into at least two frequency band signals and amplifier means for amplifying the frequency band signals, whereby the circuit further comprises control means for the generation of at least first and second control signals which control the amplification of the frequency band signals and means for including the amplified frequency band signals into the output signal.
• the invention further relates to a circuit for transforming an audio signal into an output signal.
• a hearing instrument according to the preamble is known from Gennum Corporation's "GS3027/GS3028 Preliminary data sheet", April 1997.
• Hearing instruments often comprise AGC-units.
• These AGC-units are used to amplify received signals in order to achieve an improved perception of those signals by a hearing-impaired user of the hearing instrument.
• the amplification of the AGC-units depends on the frequency and the amplitude of the received signals. For instance, for people who are not able to hear high frequency components very well, the AGC-units can be configured in such a way that low frequency components of the received signals above a certain amplitude are compressed, which leads to an improved perception of the high frequency components.
• a hearing instrument in which this concept is implemented is often referred to as a TILL hearing instrument, i.e. a Treble Increase at Low signal Levels hearing instrument. Otherwise, for people who are not able to hear low frequency components very well, the AGC-units can be configured in such a way that high frequency components of the received signals above a certain amplitude are compressed, which leads to an improved perception of the low frequency components.
• a hearing instrument in which this concept is implemented is often referred to as a BILL hearing instrument, i.e. a Bass Increase at Low signal Levels hearing instrument.
• the known hearing instrument can be configured as a BELL or as a TELL hearing instrument.
• the hearing instrument comprises thereto a band split filter by means of which a received audio signal is divided into a low frequency band and a high frequency band signal. Thereupon, these frequency band signals are amplified in two AGC-units, one for each frequency band signal.
• the hearing instrument further comprises two variable resistors, one for each AGC-unit, for the purpose of controlling the compression ratios of the AGC-units.
• the compression ratio corresponds to the ratio between, on the one hand, an increase in amplitude of an input signal of the AGC-unit which must be amplified and, on the other hand, the increase in amplitude of the corresponding output signal resulting from the AGC-unit.
• An object of the invention is to provide another hearing instrument, which can be conveniently configured as a BELL or as a TILL hearing instrument.
• This object is achieved in the hearing instrument according to the invention, which is characterized in that the control means are embodied so as to increase a level of the first control signal while simultaneously decreasing the level of the second control signal, or vice versa.
• the compression ratios of both AGC-units can be controlled simultaneously by the control means.
• a TELL hearing instrument can be obtained by increasing the level of the first control signal, which controls the low frequency AGC-unit, while decreasing the level of the second control signal, which controls the high frequency AGC-unit.
• the compression ratio of the first AGC-unit is increased, e.g. to 3:1, while the compression ratio of the second AGC-unit is decreased to about 1 : 1.
• a BELL hearing instrument can be obtained from the 'neutral position' by decreasing the level of the first control signal while increasing the level of the second control signal. Then the compression ratio of the first AGC-unit is decreased to about 1:1, while increasing the compression ratio of the second AGC-unit to, for example, 3:1.
• An embodiment of the hearing instrument according to the invention is characterized in that the control means comprise a single control element. By using only a single control element a relatively simple, cheap and small hearing instrument is obtained.
• Figure 1 shows a block diagram of a hearing instrument according to the invention
• Figure 2 shows a preferred embodiment of the hearing instrument according to the invention.
• Figure 3 shows the relation between, on the one hand side, the compression ratio of the two AGC-units included in the hearing instrument shown in Figure 2 and, on the other side, the rotation of the potentiometer which is also included in the hearing instrument shown in Figure 2.
• FIG. 1 shows a block diagram of a hearing instrument according to the invention.
• the hearing instrument comprises a microphone 10 for converting a received sound signal into an electric audio signal 11.
• This audio signal 11 is transformed in a circuit 12 into an electric output signal 13, which is subsequently converted to sound by an electro-acoustic converter 14.
• the audio signal 11 is first divided by a band split filter 18 into a low frequency band signal and a high frequency band signal.
• These frequency band signals are amplified by the controllable amplifiers, e.g. AGC-units, 20 and 22, which are controlled via control signals 21 and 23 by the control means 24.
• the control means can increase the level of the control signal 21 while simultaneously decreasing the level of the control signal 23, and vice versa.
• Adder 26 adds the amplified frequency band signals together and supplies the resulting electric output signal 13, possibly via an extra amplifier, to the electro- acoustic converter 14.
• FIG. 2 shows a preferred embodiment of the hearing instrument according to the invention.
• the hearing instrument comprises a microphone 10 for converting a received sound signal into an electric audio signal 11.
• This audio signal 11 is transformed in a circuit 12 into an electric output signal 13, which is subsequently converted to sound by an electro-acoustic converter 14.
• the circuit 12 includes an integrated circuit 32, i.e. the GS3027 known from the before mentioned data sheet.
• This integrated circuit 32 includes a band split filter and, coupled thereto, a high and a low frequency AGC-unit.
• the audio signal 11 is supplied to an input 30 of the integrated circuit 32, i.e. pin 7 of the GS3027.
• the band split filter divides the audio signal 11 into a low frequency band signal and a high frequency band signal.
• These frequency band signals are amplified by the AGC-units.
• the compression ratios of these AGC-units can be controlled between 1: 1 and 4: 1 via control signals 21 and 23 by means of externally applied resistors 36, 38, 40 and 42, which form the control means 24.
• the amplified frequency band signals are added together and the resulting electric output signal 13, which is present at an output 34 (i.e. pin 14 of the GS3027), is supplied to the electro-acoustic converter 14.
• the resistor 38 is a variable resistor, e.g. a linear or logarithmic potentiometer.
• a first contact of this potentiometer 38 is coupled via the resistor 36 to a first reference voltage 1:1 (i.e. pin 13 of the GS3027).
• a second contact of the potentiometer 38 is coupled via the resistor 40 to the first reference voltage 1:1.
• a wiper contact of the potentiometer 38 is coupled via the resistor 42 to a second reference voltage 4: 1 (i.e. pin 10 of the GS3027).
• the first control signal 21 is present, which is supplied to the GS3027 via pin 12.
• the control signals 21 and 23 comprise voltages which control the compression ratios of the voltage controlled AGC-units in the GS3027.
• the voltage 21, and thus the compression ratio of the low frequency AGC-unit depends on the ratio between, on the one hand, the resistance R LOI between the first contact of the potentiometer 38 and the first reference voltage 1:1 and, on the other hand, the resistance R O2 between the first contact and the second reference voltage 4:1.
• R LOI is fixed and equal to the resistance of the resistor 36 and R O2 is variable and equal to the sum of the resistance of the resistor 42 and of the resistance of the potentiometer 38 between the wiper contact and the first contact. If the wiper contact of the potentiometer 38 is rotated in negative direction, R o decreases which results in a decrease of the voltage 21. If the wiper contact of the potentiometer 38 is rotated in positive direction, R LO2 increases which results in an increase of the voltage 21.
• the voltage 23, and thus the compression ratio of the high frequency AGC-unit depends on the ratio between, on the one hand, the resistance R HII between the second contact of the potentiometer 38 and the first reference voltage 1: 1 and, on the other hand, the resistance R HI2 between the second contact and the second reference voltage 4: 1.
• R H ⁇ is fixed and equal to the resistance of the resistor 40 and R H ⁇ is variable and equal to the sum of the resistance of the resistor 42 and of the resistance of the potentiometer 38 between the wiper contact and the second contact. If the wiper contact of the potentiometer 38 is rotated in negative direction, R HO increases which results in an increase of the voltage 23. If the wiper contact of the potentiometer 38 is rotated in positive direction, R H ⁇ decreases which results in a decrease of the voltage 23.
• the resistance of the resistors 36 and 40 is equal to 20 k ⁇
• the resistance of the resistor 42 is equal to 2 k ⁇
• the resistance of the potentiometer 38 is equal to 200 k ⁇ .
• Figure 3 shows by means of two curves 50 and 52 the relation between, on the one hand side, the compression ratio of the two AGC-units included in the hearing instrument shown in Figure 2 and, on the other side, the rotation of the potentiometer 38 which is also included in the hearing instrument shown in Figure 2.
• the rotation of the potentiometer 38 (in degrees) is plotted on the horizontal axis
• the compression ratio of the AGC-units is plotted on the vertical axis.
• the curve 50 shows how the compression ratio of the low frequency AGC-unit depends on the rotation of the potentiometer 38.
• the curve 52 shows how the compression ratio of the high frequency AGC-unit depends on the rotation of the potentiometer 38.
• the control means 24 When the rotation of the potentiometer 38 is at 0 degrees, the control means 24 is in its 'neutral position', i.e. the levels of the control signals 21 and 23 are equal to each other and the compression ratios of both the AGC-units are equal to about 1.4:1. Starting from this 'neutral position', in which the hearing instrument exhibits a substantially linear behaviour, a TELL hearing instrument can be obtained by a negative rotation of the potentiometer 38. For instance, when the rotation of the potentiometer 38 is equal to -135 degrees the compression ratio of the low frequency AGC-unit is equal to 3:1, while the compression ratio of the high frequency AGC-unit is equal to 1.1:1, i.e. the high frequency AGC-unit amplifies the high frequency band signal substantially linear without compression.

Landscapes

• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Neurosurgery (AREA)
• Otolaryngology (AREA)
• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Tone Control, Compression And Expansion, Limiting Amplitude (AREA)

Priority Applications (1)

Applications Claiming Priority (4)

Publications (1)

Family

ID=8233872

Family Applications (1)

Country Status (2)

Families Citing this family (4)

Family Cites Families (6)

• 1999
  • 1999-06-21 WO PCT/IB1999/001153 patent/WO2000002418A1/en not_active Application Discontinuation
  • 1999-06-21 EP EP99923823A patent/EP1016318A1/de not_active Withdrawn

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events