Patent US4516257A successfully refreshed from Google Patents.
US4516257A
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US
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Triphonic sound system
Assignee: CBS Broadcasting Inc
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Filing: 1984-04-05
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Granted: 1985-05-07
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Expires: 2004-04-05
Abstract
Abstract A triphonic sound system in which three independent stereophonically related audio frequency source signals L, R and C are combined to derive three other audio frequency signals M, S, and T which respectively comprise (L+1.4C+R, (L-R) and (-1.4C). In a preferred transmitter embodiment, useful in television broadcasting, the audio signals S and T modulate two quadrature-related sub-carriers of the same frequency to develop two double-sideband, suppressed-carrier signals, the frequency of the subcarriers being sufficiently high as to assure a frequency gap between the lower sidebands of the modulated subcarrier signals and the audio frequency signal (L+1.4C+R). The aforementioned signals, and a pilot signal having a frequency which lies within the frequency gap, are combined and frequency-modulated onto a high frequency carrier for the purpose of transmitting the same to one or more remote receivers. The receiver is operative in response to reception of the high frequency carrier to reproduce each of the audio frequency source signals L, R and C, and includes means for reproducing conventional monophonic and two-channel stereophonic broadcasts. The described matrix equations are amenable to and useful with multi-channel television sound systems currently under consideration for future broadcast service in the United States.
Inventors
- 👤 Emil L. Torick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:44
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/86; H04H20/88; H04S; H04S3/00
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
157 words
In a triphonic sound transmission system, a transmitter comprising: means for combining three independent stereophonically related audio frequency source waves L, R and C to obtain three audio frequency signals M, S and T respectively comprising (L+1.4C+R), (L-R) and (-1.4C); means for generating two subcarriers of the same frequency and spaced 90° apart in phase; means for amplitude-modulating each subcarrier with a respective one of said audio frequency signals S and T to develop two double-sideband suppressed-carrier signals, the frequency of said subcarriers being sufficiently high as to assure a frequency gap between the lower sidebands of the modulated subcarrier signals and the said M signal; means for generating a phase reference pilot signal having a frequency which is one-half the frequency of the subcarriers and lies within said frequency gap; and means for frequency modulating the aforementioned signals onto a high frequency carrier for the purpose of transmitting the same to one or more remote receivers.
Claim 2
Dependent Claim
157 words
In a triphonic sound transmission system, a transmitter comprising: means for combining three independent stereophonically related audio frequency source waves L, R and C to obtain three audio frequency signals M, S and T respectively comprising (L+1.4C+R), (L-R) and (-1.4C); means for generating two subcarriers of the same frequency and spaced 90° apart in phase; means for amplitude-modulating each subcarrier with a respective one of said audio frequency signals S and T to develop two double-sideband suppressed-carrier signals, the frequency of said subcarriers being sufficiently high as to assure a frequency gap between the lower sidebands of the modulated subcarrier signals and the said M signal; means for generating a phase reference pilot signal having a frequency which is one-half the frequency of the subcarriers and lies within said frequency gap; and means for frequency modulating the aforementioned signals onto a high frequency carrier for the purpose of transmitting the same to one or more remote receivers.
Claim 3
Dependent Claim
35 words
A triphonic system as defined in claim 1 including receiver means operative in response to the reception of said high frequency carrier to reproduce each of the audio frequency source signals L, R and C.
Claim 4
Dependent Claim
22 words
A triphonic system as defined in claim 2 wherein said receiver means includes means for reproducing conventional monophonic and two-channel stereophonic broadcasts.
Claim 5
Dependent Claim
109 words
A triphonic sound system comprising: a transmitter including means for combining three independent stereophonically related audio frequency source signals L, C, and R to obtain three audio frequency signals M, S and T respectively comprising (L+1.4C+R), (L-R) and (-1.4C), means for amplitude-modulating each of two equal frequency quadrature-phased subcarriers with a respective one of said audio frequency signals S and T, and means for frequency modulating the aforementioned signals onto a high frequency carrier for the purpose of transmitting the same to one or more remote receivers; and receiver means operative in response to the reception of said frequency-modulated carrier for reproducing each of said audio frequency source signals.
Claim 6
Dependent Claim
109 words
A triphonic sound system comprising: a transmitter including means for combining three independent stereophonically related audio frequency source signals L, C, and R to obtain three audio frequency signals M, S and T respectively comprising (L+1.4C+R), (L-R) and (-1.4C), means for amplitude-modulating each of two equal frequency quadrature-phased subcarriers with a respective one of said audio frequency signals S and T, and means for frequency modulating the aforementioned signals onto a high frequency carrier for the purpose of transmitting the same to one or more remote receivers; and receiver means operative in response to the reception of said frequency-modulated carrier for reproducing each of said audio frequency source signals.
Claim 7
Dependent Claim
91 words
A triphonic sound system as defined in claim 4, wherein said carrier is modulated in accordance with the modulation function e.sub.m =M+p sin (ω.sub.s t/2)+S sin ω.sub.s t+T cos ω.sub.s t where p is the amplitude of a phase reference pilot signal sin (ω s t/2), and ω s =2πf s , where f s is the fundamental frequency of the subcarrier signals sin ω s t and cos ω s t, each subcarrier signal being suppressed-carrier double-sideband amplitude-modulated by a respective one of said audio frequency signals S and T.
Claim 8
Dependent Claim
31 words
A triphonic sound system as defined in claim 5, wherein f s =kf H , k is a constant, and f H =15,734 Hz, the horizontal synchronization frequency for NTSC television.
Claim 9
Dependent Claim
19 words
A triphonic sound system as defined in claim 3, wherein the constant k is selected from 2.0 or 2.5.
Claim 10
Dependent Claim
24 words
A triphonic sound system as defined in claim 4, wherein said receiver means includes means for alternatively reproducing conventional monophonic and two-channel stereophonic broadcasts.
Claim 11
Dependent Claim
68 words
A triphonic sound system as defined in claim 8, wherein said receiver means includes first and second means for combining said audio signals M and S to obtain first and second intermediate audio signals (2L+1.4C) and (2R+1.4C), respectively, and third and fourth means for combining said first and second intermediate audio signals, respectively, with said audio signal T to obtain said audio frequency source signals L and R.
Claim 12
Dependent Claim
85 words
In a triphonic sound transmission system, a transmitter comprising: means for combining three independent stereophonically related audio frequency source signals L, C, and R to obtain three audio frequency signals M, S and T respectively comprising (L+1.4C+R), (L-R) and (-1.4C), means for modulating each of two subcarriers with a respective one of said audio frequency signals S and T, and means for frequency modulating the aforementioned signals onto a high frequency carrier for the purpose of transmitting the same to one or more remote receivers.
Claim 13
Dependent Claim
85 words
In a triphonic sound transmission system, a transmitter comprising: means for combining three independent stereophonically related audio frequency source signals L, C, and R to obtain three audio frequency signals M, S and T respectively comprising (L+1.4C+R), (L-R) and (-1.4C), means for modulating each of two subcarriers with a respective one of said audio frequency signals S and T, and means for frequency modulating the aforementioned signals onto a high frequency carrier for the purpose of transmitting the same to one or more remote receivers.
Claim 14
Dependent Claim
70 words
A transmitter as defined in claim 10, wherein a first of said subcarriers is modulated by said audio frequency signal S and has a frequency which assures a frequency gap between the lower sideband of the modulated subcarrier signal and the M signal, and wherein the second of said subcarriers is modulated by said audio frequency signal T and has a frequency higher than the frequency of said first subcarrier.
Claim 15
Dependent Claim
42 words
A transmitter as defined in claim 10, wherein said subcarriers are quadrature-phased and of the same frequency, which frequency is sufficiently high as to assure a frequency gap between the lower sidebands of the modulated subcarrier signals and the said M signal.
Claim 16
Dependent Claim
114 words
A receiver for use in a triphonic sound system having a transmitter including means for combining three independent stereophonically related audio frequency source signals L, C, and R to obtain three audio frequency signals M, S and T respectively comprising (L+1.4C+R), (L-R) and (-1.4C), means for modulating each of two subcarriers with a respective one of said audio frequency signals S and T, and means for frequency modulating the aforementioned signals onto a high frequency carrier for the purpose of transmitting the same to one or more remote receivers, said receiver comprising: means operative in response to reception of said high frequency carrier for deriving said audio frequency signals M, S and T, and
Claim 17
Dependent Claim
114 words
A receiver for use in a triphonic sound system having a transmitter including means for combining three independent stereophonically related audio frequency source signals L, C, and R to obtain three audio frequency signals M, S and T respectively comprising (L+1.4C+R), (L-R) and (-1.4C), means for modulating each of two subcarriers with a respective one of said audio frequency signals S and T, and means for frequency modulating the aforementioned signals onto a high frequency carrier for the purpose of transmitting the same to one or more remote receivers, said receiver comprising: means operative in response to reception of said high frequency carrier for deriving said audio frequency signals M, S and T, and
Claim 18
Dependent Claim
22 words
means for combining said M, S and T signals to reproduce each of the audio frequency source signals L, R and C.
Claim 19
Dependent Claim
22 words
means for combining said M, S and T signals to reproduce each of the audio frequency source signals L, R and C.
Claim 20
Dependent Claim
66 words
A receiver as defined in claim 13, wherein said combining means includes first and second means for combining said audio signals M and S to obtain first and second intermediate audio signals (2L+1.4C) and (2R+1.4C), respectively, and third and fourth means for combining said first and second intermediate audio signals, respectively, with said audio signal T to obtain said audio frequency source signals L and R.
Claim 21
Dependent Claim
21 words
A receiver as defined in claim 13, wherein said receiver includes means for alternatively reproducing conventional monophonic and two-channel stereophonic broadcasts.
Claim 22
Dependent Claim
23 words
A receiver as defined in claim 13, wherein said combining means is operative to alternatively reproduce received conventional monophonic and two-channel stereophonic broadcasts.
Claim 23
Dependent Claim
142 words
In a triphonic sound system, a receiver for demodulating a high frequency carrier signal frequency modulated by first and second subcarriers respectively modulated by audio frequency signals S and T and by an audio frequency signal M, where the signals M, S and T comprise combinations of three independent stereophonically related audio frequency source signals, R, and C, said combinations comprising (L+1.4C+R), (L-R) and (-1.4C), respectively, said receiver comprising: means operative in response to said high frequency carrier for deriving said audio frequency signals M, S and T, means for combining said audio signals M and S to obtain first and second intermediate audio signals (2L+1.4C) and (2R+1.4C), respectively, means for deriving said audio signal T, and means for separately combining said audio signal T with each of said intermediate audio signals to obtain said audio frequency source signals L and R.
Claim 24
Dependent Claim
142 words
In a triphonic sound system, a receiver for demodulating a high frequency carrier signal frequency modulated by first and second subcarriers respectively modulated by audio frequency signals S and T and by an audio frequency signal M, where the signals M, S and T comprise combinations of three independent stereophonically related audio frequency source signals, R, and C, said combinations comprising (L+1.4C+R), (L-R) and (-1.4C), respectively, said receiver comprising: means operative in response to said high frequency carrier for deriving said audio frequency signals M, S and T, means for combining said audio signals M and S to obtain first and second intermediate audio signals (2L+1.4C) and (2R+1.4C), respectively, means for deriving said audio signal T, and means for separately combining said audio signal T with each of said intermediate audio signals to obtain said audio frequency source signals L and R.
References Cited (Backward Citations)
US3679832A
Cited
US4405944A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-06 | 1988-11-05 | 1989-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-06 | 1992-11-05 | 1993-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-06 | 1996-11-05 | 1997-05-07 | $7700.00 | Window Closed / Lapsed |