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Patent US4224468A successfully refreshed from Google Patents.
US4224468A
Expired / Lapsed
US
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Masking level difference adaptor for audiometers
Assignee: Individual
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Filing: 1978-10-05
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Granted: 1980-09-23
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Expires: 1998-10-05
Abstract
Abstract An adaptor is disclosed for use with audiometers to enable the measurement of the masking level difference (MLD) in a person's hearing capability. The adaptor comprises a signal channel and a noise (masker) channel which are connected respectively with the audiometer outputs and the earphones. Means are provided to apply the signal voltage and the noise voltage to respective mixers in the two channels and for selectively inverting the phase of the signal voltage at one of the mixers and for selectively inverting the phase of noise voltage at one of the misers. Various MLD test conditions can be established including binaural and monaural conditions and adjustable intensity at one ear.
Inventors
- 👤 Howard B. Calder, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:13
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/12; A61B5/121
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
299 words
An adaptor for audiometers to ascertain the masking level difference in a person's hearing, said audiometer having a signal voltage output and a noise voltage output, said adaptor comprising: a signal channel having a channel input adapted to be connected with the signal voltage output of the audiometer, a signal channel mixer, and a signal channel output adapted to be connected with one earphone of a pair of earphones, a noise channel having a channel input adapted to be connected with the noise voltage output of the audiometer, a noise channel mixer and a channel output adapted to be connected with the other earphone of the pair, said channels including circuit means coupled with both of said channel inputs for applying the signal voltage and the noise voltage to the signal channel mixer and to the noise channel mixer, said circuit means including a signal channel phase inverting means for selectively inverting the phase of the signal voltage at one of said mixers relative to the signal voltage at the other of said mixers and including a noise channel phase inverting means for selectively inverting the phase of the noise voltage at one of said mixers relative to noise voltage at the other of said mixers, each of phase inverting means and each of said mixers including an amplifying device, both of said channels having a voltage gain of unity between the respective channel input and output; wherein the signal voltages at said channel outputs are substantially equal in amplitude to the signal voltage output of the audiometer and are selectively homophasically or antiphasically related to each other and the noise voltages at said channel outputs are substantially equal in amplitude to the noise voltage output of the audiometer and are selectively homophasically or antiphasically related to each other.
Claim 2
Dependent Claim
299 words
An adaptor for audiometers to ascertain the masking level difference in a person's hearing, said audiometer having a signal voltage output and a noise voltage output, said adaptor comprising: a signal channel having a channel input adapted to be connected with the signal voltage output of the audiometer, a signal channel mixer, and a signal channel output adapted to be connected with one earphone of a pair of earphones, a noise channel having a channel input adapted to be connected with the noise voltage output of the audiometer, a noise channel mixer and a channel output adapted to be connected with the other earphone of the pair, said channels including circuit means coupled with both of said channel inputs for applying the signal voltage and the noise voltage to the signal channel mixer and to the noise channel mixer, said circuit means including a signal channel phase inverting means for selectively inverting the phase of the signal voltage at one of said mixers relative to the signal voltage at the other of said mixers and including a noise channel phase inverting means for selectively inverting the phase of the noise voltage at one of said mixers relative to noise voltage at the other of said mixers, each of phase inverting means and each of said mixers including an amplifying device, both of said channels having a voltage gain of unity between the respective channel input and output; wherein the signal voltages at said channel outputs are substantially equal in amplitude to the signal voltage output of the audiometer and are selectively homophasically or antiphasically related to each other and the noise voltages at said channel outputs are substantially equal in amplitude to the noise voltage output of the audiometer and are selectively homophasically or antiphasically related to each other.
Claim 3
Dependent Claim
48 words
The invention as defined in claim 1 wherein said phase inverting means comprises a signal channel phase inverter in said signal channel, a noise channel phase inverter in said noise channel, and selector switching means for applying selected ones of said signal and noise voltages to said mixers.
Claim 4
Dependent Claim
42 words
The invention as defined in claim 2 wherein said switching means includes means for selectively inverting the phase of the signal voltage at the noise channel mixer and for selectively inverting the phase of the noise voltage at the noise channel mixer.
Claim 5
Dependent Claim
98 words
The invention as defined in claim 3 wherein said switching means includes a first selector switch having a movable contact for selectively connecting the input of the signal channel inverter or the output of the signal channel inverter to the input of the noise channel mixer, and a second selector switch having a movable contact for selectively connecting the input of the noise channel inverter or the output of the noise channel inverter to the input of the noise channel mixer, said output of the noise channel inverter being connected with the input of the signal channel mixer.
Claim 6
Dependent Claim
124 words
The invention as defined in claim 4 wherein said signal channel includes a signal channel buffer amplifier coupled between signal channel input and the input of said signal channel inverter, a signal channel current amplifier connected with the output of the signal channel mixer, and a signal channel attenuator connected between the output of the signal channel current amplifier and said signal channel output, and wherein said noise channel includes a noise channel buffer amplifier coupled between the noise voltage channel input and the input of said noise voltage inverter, a noise channel current amplifier connected with the output of the noise channel mixer, and a noise channel attenuator connected between the output of the noise channel current amplifier and said noise channel output.
Claim 7
Dependent Claim
92 words
The invention as defined in claim 4 wherein said signal channel buffer amplifier has a gain equal to the attenuation of said signal channel attenuator and the remainder of said signal voltage channel has a combined gain of unity, and wherein said noise channel buffer amplifier has a gain equal to the attenuation of said noise channel attenuator and the remainder of said noise channel has a combined gain of unity, whereby the thermal noise produced by said channels is of negligible level compared to the thermal noise produced by said audiometer.
Claim 8
Dependent Claim
15 words
The invention as defined in claim 5 wherein said buffer amplifier is a differential amplifier.
Claim 9
Dependent Claim
75 words
The invention as defined in claim 2 including a power supply, a power supply switch, a relay having an energizing oil connected with the power supply and being energized by the power supply switch, said relay having contact means for connecting the signal channel input with the signal channel output and for connecting the noise channel input with the noise channel output when the power supply switch is turned off, whereby the adaptor is bypassed.
Claim 10
Dependent Claim
29 words
The invention as defined in claim 2 including a variable attenuator connected in one of said channels whereby a selectively adjustable voltage is produced at the respective channel output.
Claim 11
Dependent Claim
40 words
The invention as defined in claim 4 wherein the movable contacts of the first selector switch and the second selector switch each is selectively disconnectible from the respective inverter input or output, whereby monaural signals are presented at the earphones.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-09-23 | 1984-03-24 | 1984-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-23 | 1988-03-24 | 1988-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-23 | 1992-03-24 | 1992-09-23 | $7700.00 | Window Closed / Lapsed |