Patent USRE28932E successfully refreshed from Google Patents.
US3889104A
Expired / Lapsed
US
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Altitude digitizer
Assignee: Aero Industries Inc
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Filing: 1974-04-08
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Granted: 1975-06-10
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Expires: 1994-04-08
Abstract
Abstract Apparatus for providing a digital signal for an aircraft transponder indicating aircraft altitude with a unique sensor forming part of an oscillator, a counter which accumulates counts from the sensor during a predetermined gating period, a ROM which is addressed during a further gating period to apply a sequence of digital numbers to a comparator. The address indicating one thousand foot increments a second counter which receives pulses from the sensor together with the first counter after the comparator indicates the ROM number exceeds the first counter number so that the number in the second counter indicates one hundred foot and 10 foot increments when the comparator indicates the first counter number equals the ROM output to the comparator and gating for applying the outputs of the second counter and ROM address to the transponder for transmission. In one embodiment structure for providing barometric correction is included.
Inventors
- 👤 Philip L Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:03
CPC Classifications
G; G01; G01L; G01L9/00; G01L9/12; G01L9/0033; G01L9/0036; G01L9/0041; G01L9/0072; G01L9/0082; G01L9/0086; G01L9/10
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
272 words
An electrical circuit for providing a digital output signal to an aircraft transponder comprising: means for producing a pulse train having a frequency which varies as a function of altitude, gating means for producing a signal defining a first gating period in which pulses from said producing means are counted and a second gating period in which counted pulses are employed to generate said digital output signal, counter means connected to said gating means and to said producing means for receiving and accumulating a count of pulses from said producing means during said first gating period, a read only memory having a plurality of output states each indicative of a count and corresponding to an address which is associated with a given number of first foot increments of altitude, comparator means connected to said read only memory and to said counter means for providing a first output when the count in said said counter means exceeds an applied output state of said read only memory and a second output when the count in said counter is equal to or less than the applied output state of said read only memory, addressing means connected to said gating means and said read only memory for successively applying different addresses to said read only memory, during said second gating period, to cause said read only memory to apply successive output states associated with increasing numbers of first increments to said read only memory, and output gate means connected to said addressing means for producing a digital signal from the address applied to said read-only memory after said comparator means shifts to said second output state.
Claim 2
Dependent Claim
272 words
An electrical circuit for providing a digital output signal to an aircraft transponder comprising: means for producing a pulse train having a frequency which varies as a function of altitude, gating means for producing a signal defining a first gating period in which pulses from said producing means are counted and a second gating period in which counted pulses are employed to generate said digital output signal, counter means connected to said gating means and to said producing means for receiving and accumulating a count of pulses from said producing means during said first gating period, a read only memory having a plurality of output states each indicative of a count and corresponding to an address which is associated with a given number of first foot increments of altitude, comparator means connected to said read only memory and to said counter means for providing a first output when the count in said said counter means exceeds an applied output state of said read only memory and a second output when the count in said counter is equal to or less than the applied output state of said read only memory, addressing means connected to said gating means and said read only memory for successively applying different addresses to said read only memory, during said second gating period, to cause said read only memory to apply successive output states associated with increasing numbers of first increments to said read only memory, and output gate means connected to said addressing means for producing a digital signal from the address applied to said read-only memory after said comparator means shifts to said second output state.
Claim 3
Dependent Claim
114 words
A circuit as in claim 1 further including second counter means connected to said producing means and to said comparator means for receiving and accumulating a count during said compute period indicating a number of second increments of altitude, each less than said first increment, and logic means connected to said comparator means and said counter means for causing said second counter to accumulate counts during said second gating period while said comparator means provides said second output and wherein said first counter means includes means for applying pulses from said producing means to said first counter means during said second gating period and while said comparator means is providing said second output state.
Claim 4
Dependent Claim
32 words
A circuit as in claim 1 wherein said gating means includes a clock oscillator, a binary counter connected to said oscillator, and means for decoding the output states of said binary counter.
Claim 5
Dependent Claim
65 words
A circuit as in claim 3 wherein said counter means includes a pre-counter, logic gate means connected to said pre-counter, to said comparator circuit and to said decoding means for disabling said pre-counter during said second gating period while said comparator circuit is providing said first output, a further binary counter and means for connecting said further binary counter to the output of said pre-counter.
Claim 6
Dependent Claim
13 words
A circuit as in claim 1 wherein said first increment is 1,000 feet.
Claim 7
Dependent Claim
37 words
Apparatus as in claim 1 further including means for receiving an input indicating barometric pressure and means connected to said barometric indicating means and said counter means for providing an output of altitude corrected for barometric pressure.
Claim 8
Dependent Claim
17 words
Apparatus as in claim 6 wherein said output providing means includes means for producing a visual display.
Claim 9
Dependent Claim
75 words
Apparatus as in claim 6 further including means connected to said display for accumulating a count of pulses indicating altitude uncorrrected for barometric pressure, means for accumulating a count of pulses indicating the deviation of barometric pressure from standard pressure, means for indicating the direction of deviation, and means for incrementing or decrementing the count in said counter means as a function of the detected direction of deviation by a number which indicates said deviation.
Claim 10
Dependent Claim
15 words
Apparatus as in claim 8 wherein said counter means includes first and second binary counters.
Claim 11
Dependent Claim
71 words
A circuit as in claim 1 wherein said pulse producing means includes a hollow cylindrical member, a metal ring disposed about a portion of said cylindrical member, a bellows mounted in said member and having a piston movable within said member as a function of pressure to vary the capacitance between said piston and said ring, and a coil coupled to said capacitance to form a tank circuit for an oscillator.
Claim 12
Dependent Claim
70 words
A circuit as in claim 1 wherein said pulse producing means includes a hollow cylindrical member, a pair of metal discs disposed within said cylindrical member, a bellows mounted in said member between said discs so that the bellows to disc separation varies as a function of pressure to vary the capacitance between said discs, and a coil coupled to said capacitance to form a tank circuit for an oscillator.
Claim 13
Dependent Claim
14 words
A circuit as in claim 11 wherein said discs are coaxial with said member.
Claim 14
Dependent Claim
132 words
A circuit as in claim 6 wherein said providing means includes register means connected to said read only memory and said second counter means for storing a count indicating altitude uncorrected for barometric pressure, further counter means, means for applying to said further counter means a signal which varies as a function of the count stored in said register means, manual means for entering a number representing the actual barometric pressure, means connected to said manual means for converting the entered number into increments of altitude, means for incrementing or decrementing the count in said further counter means as a function of said increments of altitude to produce a count indicative of altitude corrected for barometric pressure, visual display means connected to said further counter means for providing a display of altitude.
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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) | 1978-06-09 | 1978-12-09 | 1979-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-09 | 1982-12-09 | 1983-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-09 | 1986-12-09 | 1987-06-10 | $7700.00 | Window Closed / Lapsed |