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US3885228A
Expired / Lapsed
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Fail-safe electronic encoder for selectively operating railway signal indicator
Assignee: Individual
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Filing: 1973-06-05
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Granted: 1975-05-20
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Expires: 1993-06-05
Abstract
Abstract A fair-safe electronic encoder for selectively producing code tones having different frequencies for transmission to a frequency-responsive signal indicator. The encoder is composed of a high-frequency primary source whose output is applied through a first checking device to a programmable frequency divider whose operating ratio is selectable to produce any one of a plurality of code tones. The output of the frequency divider is fed to the output or driver stage through a second checking device. The first checking device transfers the output of the primary source to the divider only if the frequency thereof lies within a narrow tolerance range, whereas the second checking device transfers the code tone produced by the divider only if the frequency thereof has a proper value, whereby no output is yielded by the encoder should a defect arise in the primary frequency source, in the divider or in any other stage of the encoder.
Inventors
- 👤 Martin J Katz
- 👤 William A Gesualdi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:48
CPC Classifications
B; B61; B61L; B61L1/00; B61L1/18; B61L1/181; B61L1/188; H; H03; H03B; H03B19/00; H03K; H03K21/00; H03K21/08
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
227 words
A fail-safe electronic encoder system adapted to selectively produce code tones of different frequency for operating a frequency-responsive railway signal indicator, said indicator displaying signals whose aspect is determined by the frequency of the applied code tone except for the most restrictive aspect which is presented only in the absence of a code tone, said system comprising: A. a high-frequency primary source; B. a programmable frequency divider coupled to the output of said source and including means to select one of several operating ratios whereby the divider yields any one of a plurality of low-frequency code tones each having a different frequency, said code tones having normal frequency values; C. a drive stage coupled to the output of said divider to supply the selected code tone to said indicator, and D. fail-safe check means to inhibit the output of said system in the event the frequency of said source deviates beyond a narrow tolerance range or the frequency or the selected code tone yielded by said divider departs from its normal value, whereby no code tone is supplied to said indicator in either event, said fail-safe check means yielding an output only if the input thereto is correct and the check means is functioning properly, the output being inhibited in the event of an incorrect input to the check means or a malfunction of the check means.
Claim 2
Dependent Claim
227 words
A fail-safe electronic encoder system adapted to selectively produce code tones of different frequency for operating a frequency-responsive railway signal indicator, said indicator displaying signals whose aspect is determined by the frequency of the applied code tone except for the most restrictive aspect which is presented only in the absence of a code tone, said system comprising: A. a high-frequency primary source; B. a programmable frequency divider coupled to the output of said source and including means to select one of several operating ratios whereby the divider yields any one of a plurality of low-frequency code tones each having a different frequency, said code tones having normal frequency values; C. a drive stage coupled to the output of said divider to supply the selected code tone to said indicator, and D. fail-safe check means to inhibit the output of said system in the event the frequency of said source deviates beyond a narrow tolerance range or the frequency or the selected code tone yielded by said divider departs from its normal value, whereby no code tone is supplied to said indicator in either event, said fail-safe check means yielding an output only if the input thereto is correct and the check means is functioning properly, the output being inhibited in the event of an incorrect input to the check means or a malfunction of the check means.
Claim 3
Dependent Claim
61 words
An electronic encoder as set forth in claim 1, wherein said check means includes a first-checking device interposed between said primary source and said divider to interrupt the connection therebetween in the event the frequency of said source deviates from said narrow tolerance range, whereby the divider then produces a zero output and no code tone is supplied to said indicator.
Claim 4
Dependent Claim
48 words
A system as set forth in claim 1, wherein said check means includes a second checking device interposed between said divider and said driver stage to interrupt the connection therebetween in the event the frequency of the code tone yielded by the divider differs from its normal value.
Claim 5
Dependent Claim
19 words
A system as set forth in claim 1 wherein said primary source is constituted by a stable high-frequency oscillator.
Claim 6
Dependent Claim
34 words
A system as set forth in claim 1, wherein said divider is constituted by a plurality of successively connected stages each dividing by a ratio determined by associated programming lines responsive to external circuits.
Claim 7
Dependent Claim
19 words
A system as set forth in claim 5 wherein said programmable frequency divider includes at least five programming lines.
Claim 8
Dependent Claim
45 words
A system as set forth in claim 1, wherein said first checking device includes an active filter haviNg a very narrow bandwidth so that only the desired frequency is passed at full amplitude, the amplitude diminishing sharply as the frequency departs from its assigned value.
Claim 9
Dependent Claim
44 words
A system as set forth in claim 7, further including a Schmitt trigger coupled to the output of said active filter, said trigger being set to produce an output only when the amplitude of the signal from the filter exceeds a predetermined threshold level.
Claim 10
Dependent Claim
63 words
A system as set forth in claim 3, wherein said second checking device includes a first single shot device coupled to the output of said divider and a second single shot coupled to the output of said first single shot, and an adjustable time delay network associated with each single shot to provide a time delay interval dependent on the selected code tones.
Claim 11
Dependent Claim
45 words
A system as set forth in claim 9 further including a switching circuit operatively coupled to said first and second single shot devices and switched thereby to pass a code tone to said driver stage only when the code tone has a normal frequency value.
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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) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |