US3845249A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-frequency receiver
Assignee: U S Holding Co Inc
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Filing: 1973-03-09
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Granted: 1974-10-29
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Expires: 1993-03-09
Abstract
Abstract Multi-frequency receivers or voice frequency are employed in telecommunication systems to validate and receive digital signals from stations having multi-frequency control signalling facilities, and to receive digital information from similarly equipped data transmitting stations. Each receiver provides a number of validating tests which it performs on the received signals prior to passing the signals to translators and decoders. The signals most frequently used in telephone practice in the United States comprise the standard eight tone, two group signals which are checked as to frequency, duration, the presence of one tone per group, minimum amplitude level and signal amplitude. In the validation process employed by the disclosed receiver, the voltages of each group output are summed, the summation voltage being necessary to trigger an output. Also, the input signals must be terminated before output signals will be generated.
Inventors
- 👤 D Sellari
- 👤 H Richard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:48
CPC Classifications
H; H04; H04Q; H04Q1/00; H04Q1/18; H04Q1/30; H04Q1/44; H04Q1/444; H04Q1/45; H04Q1/453
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
156 words
A multi-frequency receiver for receiving individual frequency tones comprising; a plurality of band pass filters each selective of a different frequency, said filters being grouped into a first and a second group, means for temporarily storing signals passed by said filters, validating means receptive to signals from said filters to include means for summing the signals receivEd from each group and means responsive to the summed signal exceeding a predetermined threshold level for emitting a timing start signal which causes the temporary storage of the signals passed by said filters in said storage means, timing means responsive to said timing start signal for timing the duration of signals received by said summing means, and output means operative after the termination of said frequency signals to said filters and the receipt of the validity control signal from said timing means for causing the transmission of the temporarily stored signals from the storage means to a decoding device.
Claim 2
Dependent Claim
156 words
A multi-frequency receiver for receiving individual frequency tones comprising; a plurality of band pass filters each selective of a different frequency, said filters being grouped into a first and a second group, means for temporarily storing signals passed by said filters, validating means receptive to signals from said filters to include means for summing the signals receivEd from each group and means responsive to the summed signal exceeding a predetermined threshold level for emitting a timing start signal which causes the temporary storage of the signals passed by said filters in said storage means, timing means responsive to said timing start signal for timing the duration of signals received by said summing means, and output means operative after the termination of said frequency signals to said filters and the receipt of the validity control signal from said timing means for causing the transmission of the temporarily stored signals from the storage means to a decoding device.
Claim 3
Dependent Claim
16 words
A receiver as claimed in claim 1, wherein said summing means includes integrated circuit operational amplifier.
Claim 4
Dependent Claim
28 words
A receiver as claimed in claim 1, wherein said summing means is voltage sensitive to sum the amplitudes of the voltage of the signals received by said filters.
Claim 5
Dependent Claim
202 words
A multi-frequency receiver for receiving individual tones of multi-frequency signals, wherein each of said tones comprises one or more signals in either a high or a low frequency group within the voice frequency range, the invention comprising: a plurality of combined filtering and amplifying stages for passing only a selected signal the each group within said range, a plurality of frequency selective stages with a separate filter for each frequency selected, means commonly connected to the filters of each group and responsive to a frequency signal transmitted through a filter of each group for producing a voltage output derived from said signal; wherein the means for producing a voltage includes means for checking said selected signals individually against predetermined minimum standards for amplitude, means for summing the voltage of both said signals, means for checking the duration of continuing occurrence for a predetermined period of both said signals, means responsive to th summed signal exceeding a predetermied reference amplitude for passing a validity control signal, and means operative after the termination of both said selected signals from said filters and the receipt of the validity control signal for passing an acceptance signal for transmission to an output circuit of said selected signals.
Claim 6
Dependent Claim
202 words
A multi-frequency receiver for receiving individual tones of multi-frequency signals, wherein each of said tones comprises one or more signals in either a high or a low frequency group within the voice frequency range, the invention comprising: a plurality of combined filtering and amplifying stages for passing only a selected signal the each group within said range, a plurality of frequency selective stages with a separate filter for each frequency selected, means commonly connected to the filters of each group and responsive to a frequency signal transmitted through a filter of each group for producing a voltage output derived from said signal; wherein the means for producing a voltage includes means for checking said selected signals individually against predetermined minimum standards for amplitude, means for summing the voltage of both said signals, means for checking the duration of continuing occurrence for a predetermined period of both said signals, means responsive to th summed signal exceeding a predetermied reference amplitude for passing a validity control signal, and means operative after the termination of both said selected signals from said filters and the receipt of the validity control signal for passing an acceptance signal for transmission to an output circuit of said selected signals.
Claim 7
Dependent Claim
17 words
A receiver as claimed in claim 4, wherein said summing means comprises a voltage sensitive operational amplifier.
Claim 8
Dependent Claim
47 words
A receiver as claimed in claim 5, wherein there are means individual to each frequency selective filter for temporarily storing signals passed by the filters, and means responsive to the end of said duration and before termination of input signals for preventing temporary storage of additional signals.
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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) | 1977-10-28 | 1978-04-29 | 1978-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-28 | 1982-04-29 | 1982-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-28 | 1986-04-29 | 1986-10-29 | $7700.00 | Window Closed / Lapsed |