US4696035A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for expanding the stereo base of stereophonic acoustic diffusion apparatus
Assignee: STMicroelectronics SRL
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Filing: 1986-07-28
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Granted: 1987-09-22
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Expires: 2006-07-28
Abstract
Abstract A first and a second input signal, constituting a stereophonic pair are amplified in respective direct amplifier means so as to obtain a first and a second output signal. In order to obtain the expansion of the stereo base, said output signals are added by adder means in a desired phase relationship, chosen between phase coincidence and phase opposition, and the sum signal thus produced is processed by a feedback block having a desired transfer function, and is then superimposed on the first input signal with opposite phase, and is superimposed on said second input signal with opposite or equal phase, according to whether said output signals are added respectively in phase coincidence of phase opposition. The feedback block preferably includes a band pass filter, and its gain is externally programmable.
Inventors
- 👤 Guido Torelli
- 👤 Alejandro de la Plaza
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:00
CPC Classifications
H; H04; H04S; H04S1/00; H04S1/002
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
129 words
A system for expanding the stereo base for stereophonic acoustic diffusion apparatus, in which a first and a second input signal, constituting a stereophonic pair, are amplified in respective direct amplifier means, in order to obtain a first and a second output signal, wherein, in order to expand the stereo base, said output signals are added by adder means in a predetermined phase relationship, chosen between phase coincidence and phase opposition, and the sum signal thus produced is processed by a feedback block having a predetermined transfer function, and is then superimposed on the first input signal with opposite phase, and is superimposed on said second input signal in phase opposition or phase coincidence, depending on whether said output signals are added respectively in phase coincidence or phase opposition.
Claim 2
Independent Claim
129 words
A system for expanding the stereo base for stereophonic acoustic diffusion apparatus, in which a first and a second input signal, constituting a stereophonic pair, are amplified in respective direct amplifier means, in order to obtain a first and a second output signal, wherein, in order to expand the stereo base, said output signals are added by adder means in a predetermined phase relationship, chosen between phase coincidence and phase opposition, and the sum signal thus produced is processed by a feedback block having a predetermined transfer function, and is then superimposed on the first input signal with opposite phase, and is superimposed on said second input signal in phase opposition or phase coincidence, depending on whether said output signals are added respectively in phase coincidence or phase opposition.
Claim 3
Dependent Claim
19 words
A system for expanding the stereo base according to claim 1, wherein said feedback block includes a band-pass filter.
Claim 4
Dependent Claim
20 words
A system for expanding the stereo base according to claim 1, wherein said direct amplifier means include respective low-pass filters.
Claim 5
Dependent Claim
27 words
A system for expanding the stereo base according to claim 1, wherein the transfer function at a center of the band of said feedback block is programmable.
Claim 6
Dependent Claim
20 words
A system for expanding the stereo base according to claim 1, which is implemented according to the full differential technique.
Claim 7
Dependent Claim
47 words
A system for expanding the stereo base according to claim 1, wherein each of said amplifier means of said first and second input signal is an inverting operational amplifier, having a first series impedance on its input and a second impedance connecting its output with its input.
Claim 8
Dependent Claim
62 words
A system for expanding the stereo base according to claim 6, wherein said adder means and said feedback block consist of an H-like symmetrical network of impedances, two external ends of said H-like network being connected to the respective outputs of said operational amplifiers, the other two ends of the H-like network being connected to the respective inputs of said operational amplifiers.
Claim 9
Dependent Claim
30 words
A system for expanding the stereo base according to claim 7, wherein a value of the impedance in a common section of said H-like network is substantially equal to zero.
References Cited (Backward Citations)
US4442546A
Cited
US4498060A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-09-21 | 1991-03-23 | 1991-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-09-21 | 1995-03-23 | 1995-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-09-21 | 1999-03-23 | 1999-09-22 | $7700.00 | Window Closed / Lapsed |