US3686431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fm-fm audio multiplex unit for television broadcasting system
Assignee: Toshiba Corp
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Filing: 1971-12-02
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Granted: 1972-08-22
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Expires: 1991-12-02
Abstract
Abstract An FM-FM audio multiplex unit for television broadcasting systems comprising a multivibrator type frequency modulator having a multivibrator for producing sub channel signals frequency modulated by audio sub channel signals, means for producing signals having double the frequency of horizontal synchronizing signals and an automatic phase controller for controlling the carrier frequency of the sub channel signals, the phase controller including a reference signal oscillator, first and second mixers for mixing the carrier signals in the sub channel signals and the signals having double the frequency of horizontal synchronizing signals with reference signals to obtain signals having high frequencies, first and second divider sections for dividing the frequencies of output signals from the first and second mixers to obtain signals having low frequencies and a phase detector for comparing the phases of output signals from the first and second dividers each other thereby making small the frequency variation of the horizontal synchronizing signals and the sub carrier signals, and resulting in causing the carrier signals of the sub channel signals to be synchronized with those having double the frequency of the horizontal synchronizing signals.
Inventors
- 👤 Kouichi Kitaoka
- 👤 Taku Ichihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:16
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/86; H04H20/88; H04J; H04J1/00; H04J1/20; H04N; H04N5/00; H04N5/38; H04N7/00; H04N7/06
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
255 words
FM-FM audio multiplex unit for television broadcasting systems comprising a multivibrator type frequency modulator having an astable multivibrator, the modulator producing sub channel signals frequency-modulated by audio sub channel signals, means for producing horizontal synchronizing signals, an automatic phase controller connected to both of the modulator and the horizontal synchronizing signal producing means for controlling the carrier frequency of the sub channel signals, means connected to the modulator for mixing the sub channel signals from the modulator with main channel signals, and means connected to the mixing means for frequency modulating main carrier signals by the output signals from the mixing means, wherein said automatic phase controller comprises a reference signals oscillator, a first mixer connected to both of the horizontal synchronizing signal producing means and the oscillator for mixing the horizontal synchronizing signals with the reference signals, a first divider section connected to the first mixer for dividing the frequency of the output signals from the first mixer, a second mixer connected to both of the modulator and the oscillator for mixing the sub channel signals with the reference signals, a second divider section connected to the second mixer for dividing the frequency of the output signals from the second mixer, and a phase detector connected between the both of the first and second dividers and the modulator, for obtaining the signals corresponding to the phase difference between the output signals from the first and second divider sections which control the frequency of the sub carrier signals with reference to the hOrizontal synchronizing signals.
Claim 2
Dependent Claim
255 words
FM-FM audio multiplex unit for television broadcasting systems comprising a multivibrator type frequency modulator having an astable multivibrator, the modulator producing sub channel signals frequency-modulated by audio sub channel signals, means for producing horizontal synchronizing signals, an automatic phase controller connected to both of the modulator and the horizontal synchronizing signal producing means for controlling the carrier frequency of the sub channel signals, means connected to the modulator for mixing the sub channel signals from the modulator with main channel signals, and means connected to the mixing means for frequency modulating main carrier signals by the output signals from the mixing means, wherein said automatic phase controller comprises a reference signals oscillator, a first mixer connected to both of the horizontal synchronizing signal producing means and the oscillator for mixing the horizontal synchronizing signals with the reference signals, a first divider section connected to the first mixer for dividing the frequency of the output signals from the first mixer, a second mixer connected to both of the modulator and the oscillator for mixing the sub channel signals with the reference signals, a second divider section connected to the second mixer for dividing the frequency of the output signals from the second mixer, and a phase detector connected between the both of the first and second dividers and the modulator, for obtaining the signals corresponding to the phase difference between the output signals from the first and second divider sections which control the frequency of the sub carrier signals with reference to the hOrizontal synchronizing signals.
Claim 3
Dependent Claim
26 words
The FM-FM audio multiplex unit according to claim 1 wherein said reference signal oscillator generates signals having higher frequencies than those of the sub carrier signals.
Claim 4
Dependent Claim
87 words
The FM-FM audio multiplex unit according to claim 2 wherein said horizontal synchronizing signal producing means comprises a synchronizing separator which is supplied with the composite signal comprising video signals and horizontal synchronizing signals and produces the horizontal synchronizing signals and a doubler supplied with the synchronizing signals for producing the signals having double the frequency of the synchronizing signals and said phase detector controls the modulator to cause the sub carrier signals to be synchronized with signals having double the frequency of the horizontal synchronizing signals.
Claim 5
Dependent Claim
75 words
The FM-FM audio multiplex unit according to claim 3 wherein said synchronizing signal producing means further comprises a buffer amplifier supplied with the composite signal whose output terminal is connected to said synchronizing separator, a differentiator connected to the output terminal of the separator, a monostable multivibrator connected to the output terminal of the differentiator, whose output terminal is connected to said doubler, and a wave shaper connected to the output terminal of the doubler.
Claim 6
Dependent Claim
59 words
The FM-FM audio multiplex unit according to claim 2 wherein said first and second devider sections each comprise a series connection of a limiter supplied with the output signals from the mixer, a Schmitt circuit, a first buffer amplifier, a divider, a second buffer amplifier and a band pass filter whose output terminal is connected to the phase detector.
Claim 7
Dependent Claim
54 words
The FM-FM audio multiplex according to claim 2 wherein said multivibrator type frequency modulator includes a differential amplifier connected between the phase detector and the multivibrator supplied with the sub channel signals, which compares the sub channel signals with the output signals from the phase detector to control the repetition frequency of the multivibrator.
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) | 1975-08-22 | 1976-02-21 | 1976-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-22 | 1980-02-21 | 1980-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-22 | 1984-02-21 | 1984-08-22 | $7700.00 | Window Closed / Lapsed |