US4236041A
Expired / Lapsed
US
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Stereophonic signal indicating apparatus
Assignee: H H SCOTT Inc
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Filing: 1979-04-13
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Granted: 1980-11-25
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Expires: 1999-04-13
Abstract
Abstract This disclosure is concerned with resolving monophonic-stereophonic signal reception indication ambiguities through the development of channel difference signals, by appropriate filtering and compression, that distinguish the stereophonic mode.
Inventors
- 👤 Richard D. Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:02
CPC Classifications
H; H04; H04H; H04H40/00; H04H40/18; H04H40/27; H04H40/36; H04H40/45
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
190 words
In stereophonic signal receiving apparatus and the like provided with means for receiving pairs of signals and a pilot tone signal transmission, apparatus for indicating if said pairs of signals are stereophonic transmissions, said apparatus having, in combination, a pair of similar filter means, one connected to receive each of the said pairs of signals; a pair of similar signal compression means, one connected to each of the filter means, for compressing the respective filtered signals; phase inverter means connected to one of the signal compression means and to a terminal in common with the output of the other signal compression means; summing and detecting means connected with said common terminal for producing a d.c. voltage indicative of the resultant signal at the said common terminal which is significantly different for stereophonic and monophonic signal inputs to the compression means; means connected to said summing and detecting means and responsive to said d.c. voltage for indicating the reception of stereophonic pairs of signals; means for detecting said pilot tone signal transmission; and means for indicating stereophonic signal reception if both the said d.c. voltage and pilot tone detection are present.
Claim 2
Dependent Claim
190 words
In stereophonic signal receiving apparatus and the like provided with means for receiving pairs of signals and a pilot tone signal transmission, apparatus for indicating if said pairs of signals are stereophonic transmissions, said apparatus having, in combination, a pair of similar filter means, one connected to receive each of the said pairs of signals; a pair of similar signal compression means, one connected to each of the filter means, for compressing the respective filtered signals; phase inverter means connected to one of the signal compression means and to a terminal in common with the output of the other signal compression means; summing and detecting means connected with said common terminal for producing a d.c. voltage indicative of the resultant signal at the said common terminal which is significantly different for stereophonic and monophonic signal inputs to the compression means; means connected to said summing and detecting means and responsive to said d.c. voltage for indicating the reception of stereophonic pairs of signals; means for detecting said pilot tone signal transmission; and means for indicating stereophonic signal reception if both the said d.c. voltage and pilot tone detection are present.
Claim 3
Dependent Claim
17 words
Apparatus as claimed in claim 1 wherein said compression means comprises a pair of similar logarithmic amplifiers.
Claim 4
Dependent Claim
16 words
Apparatus as claimed in claim 1 wherein said pair of similar filter means comprise band-pass filters.
Claim 5
Dependent Claim
29 words
Apparatus as claimed in claim 1 and in which said indicating means comprises a pair of indicators separately responsive to each of the d.c. voltage and pilot tone detection.
Claim 6
Dependent Claim
31 words
Apparatus as claimed in claim 1 and in which said indicating means comprises common indicator means responsive to the simultaneity of both the said d.c. voltage and the pilot tone detection.
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) | 1983-11-25 | 1984-05-26 | 1984-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-25 | 1988-05-26 | 1988-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-25 | 1992-05-26 | 1992-11-25 | $7700.00 | Window Closed / Lapsed |