US3873772A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Speech controlled switching arrangement
Assignee: Compur Werk GmbH and Co
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Filing: 1973-07-30
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Granted: 1975-03-25
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Expires: 1993-07-30
Abstract
Abstract To differentiate speech on an incoming line from control tones, such as engaged tone signals, busy signals, or other non-speech frequencies, so that associated recording apparatus will not be activated by non-speech frequencies but will be activated by speech frequencies, the incoming signal is fed to a discriminator which discriminates on the basis of time dependent frequency variations (i.e. in the intervals between changes in frequency which in the case of speech are different and much shorter than in the case of control tone signals), rather than on the conventional basis of control tones and speech being of different frequencies. Control tones, since they are of substantially constant frequency, even though intermittent and separated by pauses, will not activate an associated switching device to start the operation of the associated recorder. On the other hand, signals of varying frequency or modulated frequency, as in speech, will activate the switching device. This is accomplished in one form of system by passing the incoming signal successively through an amplitude limiter, a discriminator, a separator unit, an amplifier, and a comparator stage, the output of which activates a switching device.
Inventors
- 👤 Ernst Dumler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:37
CPC Classifications
G; G10; G10L; G10L25/00; G10L25/78; H; H04; H04B; H04B3/00; H04B3/02; H04B3/20; H04Q; H04Q1/00; H04Q1/18; H04Q1/30; H04Q1/44; H04Q1/444; H04Q1/446; H04Q1/4465
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
147 words
Speech-operated switching apparatus for controlling a switch unit adapted to control a recording appliance in a telephone answering and message recording system, which apparatus is responsive to input speech signals and to other input signals of substantially constant frequency arriving from a telephone line, said apparatus comprising: a. means responsive to said input signals for converting said input signals into signals which change in amplitude, b. means responsive to the signals from said last named means for providing output signals which exceed a certain treshold when the frequency of said input signals changes at a rate corresponding to the rate of change of the frequency of said speech signals, and c. means for operating said switch unit when the interval between successive ones of said output signals is less than a certain interval which is characteristic of time dependent variations in the frequency of said speech signals.
Claim 2
Dependent Claim
147 words
Speech-operated switching apparatus for controlling a switch unit adapted to control a recording appliance in a telephone answering and message recording system, which apparatus is responsive to input speech signals and to other input signals of substantially constant frequency arriving from a telephone line, said apparatus comprising: a. means responsive to said input signals for converting said input signals into signals which change in amplitude, b. means responsive to the signals from said last named means for providing output signals which exceed a certain treshold when the frequency of said input signals changes at a rate corresponding to the rate of change of the frequency of said speech signals, and c. means for operating said switch unit when the interval between successive ones of said output signals is less than a certain interval which is characteristic of time dependent variations in the frequency of said speech signals.
Claim 3
Dependent Claim
57 words
The invention as set forth in claim 1 wherein said means for operating said switch unit comprises a comparator stage including first and second transistor stages connected in series, said first and second stages having R/C input circuits each having a different charging time constant, and means for applying said output signals simultaneously to said input circuits.
Claim 4
Dependent Claim
106 words
The invention as set forth in claim 2 wherein said first transistor stage includes a PNP transistor and said second transistor stage includes an NPN transistor, the collector emitter paths of said transistors being connected in series, means for connecting said series connected paths to said switch unit, a voltage doubler circuit being connected to the base of the transistor in one of said first and second stages, and a capacitor being connected to the base of the transistor in the other of said transistor stages, said output signal applying means being connected to the input of said voltage doubler circuit and to said last-named capacitor.
Claim 5
Dependent Claim
82 words
The invention as set forth in claim 1 wherein said converting means comprises differentiating means, and wherein said means for providing output signals includes: i. means responsive to the signals from said differentiating means for providing an output signal level which varies in accordance with the time variations in the occurrence of said signals from said differentiating means, and ii. coupling means responsive to said output signal level for transmitting signals which change in amplitude, said coupling means providing said output signals.
Claim 6
Dependent Claim
16 words
The invention as set forth in claim 4 wherein said differentiating means is a flank discriminator.
Claim 7
Dependent Claim
57 words
The invention as set forth in claim 4 wherein said differentiating means comprises a series capacitor and a shunt resistor across which said input signals are applied; and wherein said output signal level providing means comprises a rectifying circuit connected to the junction of said resistor and capacitor; and wherein said coupling means is a coupling capacitor.
Claim 8
Dependent Claim
40 words
The invention as set forth in claim 6 including an amplitude limiter for converting said input signals into square waves repetitive at the frequency of said input signals for applying said input signals across said series capacitor and shunt resistor.
Claim 9
Dependent Claim
28 words
The invention as set forth in claim 7 wherein said rectifying-circuit comprises a rectifier connected to a smoothing capacitor, said coupling capacitor being connected to said smoothing capacitor.
Claim 10
Dependent Claim
57 words
The invention as set forth in claim 8 wherein said means for operating said switch unit comprises a comparator stage including first and second transistor stages connected in series, said first and second stages having R/C input circuits each having a different charging time constant, and means for applying said output signals simultaneously to said input circuits.
Claim 11
Dependent Claim
97 words
The invention as set forth in claim 9, wherein said first transistor stage includes a PNP transistor, the collector emitter paths of said transistors being connected in series, means for connecting said series connected paths to said switch unit, a voltage doubler circuit being connected to the base of the transistor in one of said first and second stages, and a capacitor being connected to the base of the transistor in the other of said transistor stages, said output signal apPlying means being connected to the input of said voltage doubler circuit and to said last-named capacitor.
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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) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |