US3855415A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Communication sound system continuously monitored
Assignee: DU KANE CORP US
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Filing: 1973-07-20
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Granted: 1974-12-17
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Expires: 1993-07-20
Abstract
Abstract A communication sound system has at least one channel terminating in a dynamic type loudspeaker, a monitoring frequency is introduced into the sound system at a relatively low energy level, at least about 10 dB below normal communication level, the frequency being near or below the lower end of the sound frequency range in the system, as for example about 27 Hz. The speaker diaphragm is maintained in continuous oscillation at the monitoring frequency as well as at audible frequencies incident to sound system operation. The energy level of the monitoring frequency is low enough so that speaker operation is not changed appreicably as far as audible speaker outut is concerned. A sensing coil electrically separate from but mechanically coupled to the voice coil of the speaker cooperates with the magnetic air gap of the speaker to generate a voltage which is amplified, passed through a band pass filter to provide a monitor frequency at the filter output so long as the monitor frequency is present in the channel. The filter output is applied to an alarm which is responsive to the presence of the monitor frequency voltages (or currents) and will indicate an alarm condition if the monitor frequency in the channel is absent.
Inventors
- 👤 R Fox
- 👤 J Altman
- 👤 C King
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:22
CPC Classifications
H; H04; H04R; H04R29/00; H04R29/007; H04R27/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
229 words
A system for indicating the operativeness of a sound channel including at least one speaker at an output end of said channel, said system having an input for a range of sound frequencies in the form of electric potentials, means for generating electric potentials at a signal frequency, means for introducing said signal frequency potentials into the channel to mix with potentials corresponding to sound frequencies normally transmitted along said channel to said speaker, said speaker being of the dynamic type having a voice coil movable axially in an annular magnetic air gap, said speaker normally being continuously energized by said signal frequency potentials as well as by sound frequency potentials, means for generating a potential from the vibration of said voice coil, said last named means including a sensing coil in proximity to said voice coil and vibrating therewith in said magnetic air gap, means for amplifying said generated potentials and filtering to derive signal frequency potentials when said channel is transmitting signal frequency potentials, and connections to feed such potentials to an alarm system having positions corresponding to the presence or absence of signal frequency potentials whereby the presence of signal frequency potentials generated in the sensing coil will indicate that the channel including the speaker is operative for communication purposes and said alarm system, in case of interruption of said signal frequency will indicate a fault.
Claim 2
Independent Claim
229 words
A system for indicating the operativeness of a sound channel including at least one speaker at an output end of said channel, said system having an input for a range of sound frequencies in the form of electric potentials, means for generating electric potentials at a signal frequency, means for introducing said signal frequency potentials into the channel to mix with potentials corresponding to sound frequencies normally transmitted along said channel to said speaker, said speaker being of the dynamic type having a voice coil movable axially in an annular magnetic air gap, said speaker normally being continuously energized by said signal frequency potentials as well as by sound frequency potentials, means for generating a potential from the vibration of said voice coil, said last named means including a sensing coil in proximity to said voice coil and vibrating therewith in said magnetic air gap, means for amplifying said generated potentials and filtering to derive signal frequency potentials when said channel is transmitting signal frequency potentials, and connections to feed such potentials to an alarm system having positions corresponding to the presence or absence of signal frequency potentials whereby the presence of signal frequency potentials generated in the sensing coil will indicate that the channel including the speaker is operative for communication purposes and said alarm system, in case of interruption of said signal frequency will indicate a fault.
Claim 3
Independent Claim
229 words
A system for indicating the operativeness of a sound channel including at least one speaker at an output end of said channel, said system having an input for a range of sound frequencies in the form of electric potentials, means for generating electric potentials at a signal frequency, means for introducing said signal frequency potentials into the channel to mix with potentials corresponding to sound frequencies normally transmitted along said channel to said speaker, said speaker being of the dynamic type having a voice coil movable axially in an annular magnetic air gap, said speaker normally being continuously energized by said signal frequency potentials as well as by sound frequency potentials, means for generating a potential from the vibration of said voice coil, said last named means including a sensing coil in proximity to said voice coil and vibrating therewith in said magnetic air gap, means for amplifying said generated potentials and filtering to derive signal frequency potentials when said channel is transmitting signal frequency potentials, and connections to feed such potentials to an alarm system having positions corresponding to the presence or absence of signal frequency potentials whereby the presence of signal frequency potentials generated in the sensing coil will indicate that the channel including the speaker is operative for communication purposes and said alarm system, in case of interruption of said signal frequency will indicate a fault.
Claim 4
Independent Claim
229 words
A system for indicating the operativeness of a sound channel including at least one speaker at an output end of said channel, said system having an input for a range of sound frequencies in the form of electric potentials, means for generating electric potentials at a signal frequency, means for introducing said signal frequency potentials into the channel to mix with potentials corresponding to sound frequencies normally transmitted along said channel to said speaker, said speaker being of the dynamic type having a voice coil movable axially in an annular magnetic air gap, said speaker normally being continuously energized by said signal frequency potentials as well as by sound frequency potentials, means for generating a potential from the vibration of said voice coil, said last named means including a sensing coil in proximity to said voice coil and vibrating therewith in said magnetic air gap, means for amplifying said generated potentials and filtering to derive signal frequency potentials when said channel is transmitting signal frequency potentials, and connections to feed such potentials to an alarm system having positions corresponding to the presence or absence of signal frequency potentials whereby the presence of signal frequency potentials generated in the sensing coil will indicate that the channel including the speaker is operative for communication purposes and said alarm system, in case of interruption of said signal frequency will indicate a fault.
Claim 5
Dependent Claim
29 words
The system according to claim 1, wherein said signal frequency potentials are introduced into the channel at a low energy level so that signal frequency reproduction is substantially inaudible.
Claim 6
Dependent Claim
53 words
The system according to claim 1, wherein a plurality of sound channels are provided, said channels having a common input and individual outputs, each channel having a speaker with its own voice coil and its own sensing coil and means for connecting the sensing coils in series to said amplifying and filtering means.
Claim 7
Dependent Claim
22 words
The method according to claim 4, wherein the signal frequency is below the audio frequency spectrum normally handled by the sound system.
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) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |