Patent US4617536A successfully refreshed from Google Patents.
US4617536A
Expired / Lapsed
US
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Amplitude modulation apparatus and method
Assignee: Baptist Medical Center of Oklahoma Inc
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Filing: 1984-06-15
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Granted: 1986-10-14
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Expires: 2004-06-15
Abstract
Abstract An apparatus and a method modulate a carrier signal so that the resultant modulated signal varies between a value substantially equal to the quiescent level of the carrier signal and peak values up to several hundred percent of the quiescent level of the carrier signal. The apparatus includes an electrical circuit for adjusting the modulating signal so that it is clamped at a reference value to prevent overmodulation. The clamped signal controls a variable resistance mechanism which forms a part of the gain determining portion of a modulator circuit including an amplifier. The amplifier modulates the carrier signal in accordance with the gain determined by the variable resistance. The variable resistance is controlled by the clamped signal so that it causes the gain of the amplifier circuit to vary between approximately one and a value greater than one. So that the apparatus can be used by a person having a hearing impediment wherein the dynamic range detectable by the user is less than the dynamic range detectable by a normal ear, the apparatus also includes a circuit which compresses a detected acoustical signal which is within a first dynamic range into an electrical modulating signal within a dynamic range which is smaller than the first dynamic range and which is within the dynamic range perceivable by the user of the apparatus.
Inventors
- 👤 Gordon L. Richard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:06
CPC Classifications
H; H04; H04R; H04R25/00; H04R25/35; H04R25/353; H03; H03C; H03C1/00; H03C1/02; H04R25/356; H04R25/60; H04R25/604; H04R25/606
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
154 words
In an amplitude modulation apparatus of the type wherein a modulating signal having a peak-to-peak value is used for modulating a carrier signal having a quiescent peak-to-peak value, the improvement comprising modulation means for providing a modulated signal having peak-to-peak values within a range, and only within said range, between a value substantially equal to said quiescent peak-to-peak value and a value which is a multiple of said quiescent peak-to-peak value, said multiple being determined by said modulating signal peak-to-peak value, said modulating signal having magnitude excursions in two directions between upper peak values and lower peak values; and said modulation means including: signal conditioning means for shifting said modulating signal by a variable amount so that said magnitude excursions in one of said two directions never exceed a predetermined value; and carrier signal modulator means, responsive to said signal conditioning means, for multiplying the magnitude of said carrier signal by variable multiplication factors.
Claim 2
Dependent Claim
154 words
In an amplitude modulation apparatus of the type wherein a modulating signal having a peak-to-peak value is used for modulating a carrier signal having a quiescent peak-to-peak value, the improvement comprising modulation means for providing a modulated signal having peak-to-peak values within a range, and only within said range, between a value substantially equal to said quiescent peak-to-peak value and a value which is a multiple of said quiescent peak-to-peak value, said multiple being determined by said modulating signal peak-to-peak value, said modulating signal having magnitude excursions in two directions between upper peak values and lower peak values; and said modulation means including: signal conditioning means for shifting said modulating signal by a variable amount so that said magnitude excursions in one of said two directions never exceed a predetermined value; and carrier signal modulator means, responsive to said signal conditioning means, for multiplying the magnitude of said carrier signal by variable multiplication factors.
Claim 3
Dependent Claim
58 words
The improvement as defined in claim 1, wherein said variable multiplication factors vary between approximately one when the magnitude of said modulating signal is at said predetermined value and a number greater than one when the magnitude of said modulating signal is at the end of one of said magnitude excursions in the other of said two directions.
Claim 4
Dependent Claim
52 words
The improvement as defined in claim 1, wherein said carrier signal modulator means includes variable resistance means for providing a resistance when the magnitude of said modulating signal is at said predetermined value and for providing a smaller resistance when the magnitude of said modulating signal is other than said predetermined value.
Claim 5
Dependent Claim
13 words
The improvement defined in claim 3, wherein said multiple is a positive number.
Claim 6
Dependent Claim
14 words
The improvement as defined in claim 3, wherein said multiple is greater than two.
Claim 7
Dependent Claim
131 words
An amplitude modulation apparatus for modulating a carrier signal with a modulating signal, said apparatus comprising: modulating signal adjustment means for modifying the amplitude of the modulating signal, said modulating signal adjustment means including: first amplifier means, having an input and an output, for amplifying the modulating signal; reference voltage means for providing a reference voltage; capacitance means for coupling the modulating signal to said input of said first amplifier means; and diode means for electrically connecting said input of said first amplifier means and said reference voltage means; and second amplifier means, responsive to said modulating signal adjustment means, for amplifying the carrier signal by variable amplification factors, said variable amplification factors being dependent upon the modified amplitude of the modulating signal at said output of said first amplifier means.
Claim 8
Dependent Claim
131 words
An amplitude modulation apparatus for modulating a carrier signal with a modulating signal, said apparatus comprising: modulating signal adjustment means for modifying the amplitude of the modulating signal, said modulating signal adjustment means including: first amplifier means, having an input and an output, for amplifying the modulating signal; reference voltage means for providing a reference voltage; capacitance means for coupling the modulating signal to said input of said first amplifier means; and diode means for electrically connecting said input of said first amplifier means and said reference voltage means; and second amplifier means, responsive to said modulating signal adjustment means, for amplifying the carrier signal by variable amplification factors, said variable amplification factors being dependent upon the modified amplitude of the modulating signal at said output of said first amplifier means.
Claim 9
Dependent Claim
85 words
An amplitude modulation apparatus for modulating a carrier signal with a modulating signal, said apparatus comprising: modulating signal adjustment means for modifying the amplitude of the modulating signal; and amplifier means, responsive to said modulating signal adjustment means, for amplifying the carrier signal by variable amplification factors, said variable amplification factors being depending upon the modified amplitude of the modulating signal, said amplifier means including variable resistance means for providing said variable amplification factors, said variable resistance being controlled by said modulating signal adjustment means.
Claim 10
Dependent Claim
85 words
An amplitude modulation apparatus for modulating a carrier signal with a modulating signal, said apparatus comprising: modulating signal adjustment means for modifying the amplitude of the modulating signal; and amplifier means, responsive to said modulating signal adjustment means, for amplifying the carrier signal by variable amplification factors, said variable amplification factors being depending upon the modified amplitude of the modulating signal, said amplifier means including variable resistance means for providing said variable amplification factors, said variable resistance being controlled by said modulating signal adjustment means.
Claim 11
Dependent Claim
26 words
An amplitude modulation apparatus as defined in claim 7, wherein said modulating signal adjustment means includes clamping means for shifting a magnitude of the modulating signal.
Claim 12
Dependent Claim
96 words
An amplitude modulation apparatus as defined in claim 8, wherein: said modulating signal adjustment means further includes: second amplifier means having an input and an output; and reference voltage means for providing a predetermined reference voltage; and said clamping means includes: a diode having a first end electrically connected to said reference voltage means and having a second end electrically connected to said input of said second amplifier means; and capacitance means having a first end for receiving the modulating signal and having a second end electrically connected to said input of said second amplifier means.
Claim 13
Dependent Claim
61 words
An amplitude modulation apparatus as defined in claim 9, wherein said variable resistance means includes a transistor electrically connected to said output of said second amplifier means, said transistor having a cut-off voltage substantially at which said transistor is maintained in response to said reference voltage means when no modulating signal is present at the first end of said capacitance means.
Claim 14
Dependent Claim
40 words
An amplitude modulation apparatus as defined in claim 7, wherein said variable resistance means includes a transistor having a cut-off voltage substantially at which said transistor is maintained by said modulating signal adjustment means when no modulating signal is present.
Claim 15
Dependent Claim
164 words
An amplitude modulation apparatus for modulating a carrier signal with a modulating signal, said apparatus comprising: modulating signal adjustment means for modifying the amplitude of the modulating signal, said modulating signal adjustment means including: first amplifier means having an input and an output; reference voltage means for providing a predetermined reference voltage; and clamping means, associated with the input of said first amplifier means and with said reference voltage means, for shifting a magnitude of the modulating signal received by said clamping means; and second amplifier means, responsive to said modulating signal adjustment means, for amplifying the carrier signal by variable amplification factors, said variable amplification factors being dependent upon the modified amplitude of the modulating signal, said second amplifier means including variable resistance means, electrically connected to the output of said first amplifier means, for providing said variable amplification factors, said variable resistance means being maintained at a maximum resistance in response to said reference voltage means when no modulating signal is present.
Claim 16
Dependent Claim
164 words
An amplitude modulation apparatus for modulating a carrier signal with a modulating signal, said apparatus comprising: modulating signal adjustment means for modifying the amplitude of the modulating signal, said modulating signal adjustment means including: first amplifier means having an input and an output; reference voltage means for providing a predetermined reference voltage; and clamping means, associated with the input of said first amplifier means and with said reference voltage means, for shifting a magnitude of the modulating signal received by said clamping means; and second amplifier means, responsive to said modulating signal adjustment means, for amplifying the carrier signal by variable amplification factors, said variable amplification factors being dependent upon the modified amplitude of the modulating signal, said second amplifier means including variable resistance means, electrically connected to the output of said first amplifier means, for providing said variable amplification factors, said variable resistance means being maintained at a maximum resistance in response to said reference voltage means when no modulating signal is present.
Claim 17
Dependent Claim
103 words
An amplitude modulation apparatus as defined in claim 12, wherein: said reference voltage means includes a first diode having its anode electrically connected to an electrical reference; said clamping means includes: a second diode having its anode electrically connected to the cathode of said first diode; and a capacitor having a first end for receiving the modulating signal and having a second end electrically connected to the cathode of said second diode and to the input of said second amplifier means; and said variable resistance means includes a transistor having a gate terminal electrically connected to the output of said second amplifier means.
Claim 18
Dependent Claim
152 words
An amplitude modulation apparatus, comprising: transducer means for transducing an acoustical signal into an electrical signal; first amplifier means having an input and an output; capacitance means for coupling said electrical signal to said input of said first amplifier means; means for providing a predetermined reference voltage; diode means electrically connected between said input of said first amplifier means and said means for providing a predetermined reference voltage; second amplifier means including an input, an output, and a variable resistance means, said variable resistance means having a resistance control terminal electrically connected to said output of said first amplifier means; carrier signal generating means for generating a carrier signal; and means for coupling said carrier signal to said input of said second amplifier means for being modulated thereby in response to the resistance of said variable resistance means, the modulated carrier signal being provided at said output of said second amplifier means.
Claim 19
Dependent Claim
152 words
An amplitude modulation apparatus, comprising: transducer means for transducing an acoustical signal into an electrical signal; first amplifier means having an input and an output; capacitance means for coupling said electrical signal to said input of said first amplifier means; means for providing a predetermined reference voltage; diode means electrically connected between said input of said first amplifier means and said means for providing a predetermined reference voltage; second amplifier means including an input, an output, and a variable resistance means, said variable resistance means having a resistance control terminal electrically connected to said output of said first amplifier means; carrier signal generating means for generating a carrier signal; and means for coupling said carrier signal to said input of said second amplifier means for being modulated thereby in response to the resistance of said variable resistance means, the modulated carrier signal being provided at said output of said second amplifier means.
Claim 20
Dependent Claim
74 words
An amplitude modulation apparatus as defined in claim 14, wherein said transducer means includes third amplifier means having an input and an output and further including: parallel circuit means including resistance means and diode means electrically connected between said input and said output of said third amplifier means; and series circuit means including another resistance means and capacitance means electrically connected between said input of said third amplifier means and an electrical reference potential.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-10-13 | 1990-04-14 | 1990-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-13 | 1994-04-14 | 1994-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-13 | 1998-04-14 | 1998-10-14 | $7700.00 | Window Closed / Lapsed |