US4555797A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hybrid loudspeaker system for converting digital signals to acoustic signals
Assignee: US Philips Corp
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Filing: 1984-09-07
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Granted: 1985-11-26
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Expires: 2004-09-07
Abstract
Abstract In a loudspeaker system for converting an n-bit digitized electric signal (6) into an acoustic signal a plurality of sections (voice coils 14.1, 14.2, 14.3, 14.p) of a digital loudspeaker (1) are driven directly by the p most significant bits of the n-bit digitized electric signal (6). The loudspeaker (1) comprises at least one additional section (14.p+1). This (p+1) th voice coil receives a signal from a digital-to-analog converter (5), the input signal of the digital-to-analog converter comprising at least the n-p least significant bits (FIG. 2). In a different embodiment the digital-to-analog converter (5) receives all the n bits of the digitized electric signal as the input signal. At least the p sections (14.1 to 14.p) which correspond to the p most significant bits are provided with means (the resistances r) for producing a signal which is a measure of the sum of their instantaneous drive signals and for applying the said signal to a signal combination unit (32) arranged in the line (10) from the output of the digital-to-analog converter (5) to the (p+1) th section (R 1 ). By means of this correction circuit the distortion in the loudspeaker system can be reduced substantially (FIG. 3b).
Inventors
- 👤 Joris A. M. Nieuwendijk
- 👤 Wilhelmus D. A. M. van Gijsel
- 👤 Georgius B. J. Sanders
- 👤 Jacob M. van Nieuwland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:24
CPC Classifications
H; H04; H04R; H04R9/00; H04R1/00; H04R1/005; H04R3/00; H04R3/04
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
133 words
A loudspeaker system for converting a digital electrical signal of N bits into an acoustic signal comprising: an electromechanical transducer device for converting an electrical signal into a mechanical quantity for driving a diaphram, said transducer including a plurality of p electrically driven sections, fewer in number than said number N bits of said digital signal, and a p+1 section for receiving an analog voltage; means for driving each of said p electrical driven sections with one bit from the most significant bits of said electrical signal; and a digital to analog converter for receiving the least significant bits of said digital electric signal, said digital to analog converter connected to said p+1 section of said transducer whereby said transducer receives p digital signals and one analog signal for generating an acoustic signal.
Claim 2
Dependent Claim
133 words
A loudspeaker system for converting a digital electrical signal of N bits into an acoustic signal comprising: an electromechanical transducer device for converting an electrical signal into a mechanical quantity for driving a diaphram, said transducer including a plurality of p electrically driven sections, fewer in number than said number N bits of said digital signal, and a p+1 section for receiving an analog voltage; means for driving each of said p electrical driven sections with one bit from the most significant bits of said electrical signal; and a digital to analog converter for receiving the least significant bits of said digital electric signal, said digital to analog converter connected to said p+1 section of said transducer whereby said transducer receives p digital signals and one analog signal for generating an acoustic signal.
Claim 3
Dependent Claim
113 words
A loudspeaker system as claimed in claim 1, wherein the digital-to-analog converter comprises an input for receiving the N-bit digitized electric signal, the output of the digital-to-analog converter is coupled to a first input of a signal combination unit having an output which is coupled to the p+1 section to drive said p+1 section and means being provided for producing a signal which is a measure of the sum of instantaneous drive signals which drive at least the p sections corresponding to the p most significant bits and for applying said signal which is a measure of the sum of the instantaneous drive signals to a second input of the signal combination unit.
Claim 4
Dependent Claim
67 words
A loudspeaker system as claimed in claim 2 further comprising means for producing a signal which is a measure of the sum of instantaneous drive signals applied to the p+1 sections, said instantaneous drive signals corresponding to the p+1 most significant bits of said digital signal and for applying said signal which is a measure of said sum to the second input of the signal combination unit.
Claim 5
Dependent Claim
112 words
A loudspeaker system as claimed in claim 2, wherein the output of the digital-to-analog converter is coupled to a first input of a second signal combination unit having an output which is coupled to a p+2 section, said means for producing a signal associated with the p sections supply said signal also to a second input of the second signal combination unit, and the p+1 and p+2 sections are further provided with means for producing a signal which is a measure of the sum of the instantaneous drive signals of at least the p+1 and p+2 sections and for applying said signal to the second input of the second signal combination unit.
Claim 6
Dependent Claim
106 words
A loudspeaker system as claimed in claim 3, wherein the output of the digital-to-analog converter is coupled to a first input of a second signal combination unit having an output which is coupled to a p+2 section to drive this section said means for producing a signal associated with the p+1 sections supply said signal also to a second input of the second signal combination unit, and the p+2 section is provided with means for producing a signal which is a measure of the instantaneous drive signal of the p+2 section and for applying said signal to the second input of the second signal combination unit.
Claim 7
Dependent Claim
158 words
A loudspeaker system for converting an N bit digitized electric signal into an acoustic signal comprising: an electroacoustic transducer for converting an electrical signal into an acoustic wave, said transducers having a plurality of sections p less than the number of digits N, and having at least one additional section p+1; means for driving each of said sections of said plurality of p sections with one bit of said digitized electrical signal; means for converting a portion of said N bits of said digitized electric signal into an analog voltage; first means for combining currents from said plurality of p transducer sections produced in response to digital signal bits applied to said plurality of p sections and providing a voltage proportional to said combined currents; and a junction for subtracting said voltage proportional to said combined currents from said analog voltage, said junction providing a signal to said additional section p+1 whereby an acoustic output signal is produced.
Claim 8
Dependent Claim
158 words
A loudspeaker system for converting an N bit digitized electric signal into an acoustic signal comprising: an electroacoustic transducer for converting an electrical signal into an acoustic wave, said transducers having a plurality of sections p less than the number of digits N, and having at least one additional section p+1; means for driving each of said sections of said plurality of p sections with one bit of said digitized electrical signal; means for converting a portion of said N bits of said digitized electric signal into an analog voltage; first means for combining currents from said plurality of p transducer sections produced in response to digital signal bits applied to said plurality of p sections and providing a voltage proportional to said combined currents; and a junction for subtracting said voltage proportional to said combined currents from said analog voltage, said junction providing a signal to said additional section p+1 whereby an acoustic output signal is produced.
Claim 9
Dependent Claim
79 words
The loudspeaker system of claim 6 wherein said transducer includes an additional p+2 section further including: a second means for combining currents produced from said p+1 and p+2 section with a current from said first means for combining currents from said plurality of p transducer sections; and a second junction for subtractively combining said analog voltage with a voltage produced by said second means for combining currents, and applying a resulting voltage to said p+2 section of said transducer.
Claim 10
Dependent Claim
69 words
The loudspeaker system of claim 7 wherein said transducer includes an additional p+2 section, further including: a second means for combining currents produced from said p+2 section with a current produced by said first means for combining; and a second junction for subtractively combining said analog voltage with a voltage produced by said second means for combining and applying a resulting voltage to said p+2 section of said transducer.
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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) | 1988-11-25 | 1989-05-27 | 1989-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-25 | 1993-05-27 | 1993-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-25 | 1997-05-27 | 1997-11-26 | $7700.00 | Window Closed / Lapsed |