Patent US3721969A successfully refreshed from Google Patents.
US3721969A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Data comminicating system having means for sensing difference between reference and data signals
Assignee: McGraw Edison Co
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Filing: 1971-02-22
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Granted: 1973-03-20
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Expires: 1991-02-22
Abstract
Abstract A data gathering system, particularly adapted for communicating of meter reading data over telephone lines, comprising data reading means, encoding means and coded data transmitting transponder means located at a remote location such as a subscriber''s home; and centrally located control means, transponder exciting means, decoding means, and utilization means. The system has a data transmission scheme using an extended baud, multilevel frequency signal system wherein values are represented by frequency differences relative to a reference frequency and the decoding apparatus adjusts in response to the reference frequency signal to compensate for transponder variations or long term drift.
Inventors
- 👤 V Steward
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:23
CPC Classifications
H; H04; H04M; H04M11/00; H04M11/002
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
131 words
A data conversion system comprising: a means for producing an input signal having a reference level and data levels varying as a function of a value to be converted; a generator means for generating a generator signal having a level approximating said input signal reference level and for controllably varying said generator signal level independently of said input signal in response to a control signal; a reference comparator means for comparing said generator signal level with said input signal reference level to produce a comparator output indicative of the difference between said generator signal level and said reference level; and an integrating means responsive to said comparator output for producing said control signal for said generator means to worry said generator signal level to substantially match said input signal reference level.
Claim 2
Dependent Claim
131 words
A data conversion system comprising: a means for producing an input signal having a reference level and data levels varying as a function of a value to be converted; a generator means for generating a generator signal having a level approximating said input signal reference level and for controllably varying said generator signal level independently of said input signal in response to a control signal; a reference comparator means for comparing said generator signal level with said input signal reference level to produce a comparator output indicative of the difference between said generator signal level and said reference level; and an integrating means responsive to said comparator output for producing said control signal for said generator means to worry said generator signal level to substantially match said input signal reference level.
Claim 3
Dependent Claim
16 words
A data conversion system as defined in claim 1 in which said levels are frequency levels.
Claim 4
Dependent Claim
20 words
A data conversion system as defined in claim 1 in which said reference comparator means comprises digital difference counter means.
Claim 5
Dependent Claim
218 words
A data conversion system comprising: an input means for providing alternately a reference signal having a selected level and a data signal having a selected level with the difference in level between said reference signal and said data signal selected to be representative of a value to be converted; a generator means for generating a generator signal having a level controllably variable independently of said data signal levels and said reference lEvel; a comparator means for alternately comparing said generator signal level with said reference signal level and said generator signal level with said data signal level to alternately produce a first comparator output indicative of the difference between said generator signal level and said reference signal level and a second comparator output indicative of the difference between said generator signal level and said data signal level; and a means responsive to said comparator outputs for providing control signals to said comparator means to alternately vary said generator signal level to substantially match said reference signal level and to vary said generator signal level to substantially match said data signal level, and for providing an output representative of the difference between said generator signal level when matched to said reference signal level and when matched to said data signal level to thereby represent said value to be converted.
Claim 6
Dependent Claim
218 words
A data conversion system comprising: an input means for providing alternately a reference signal having a selected level and a data signal having a selected level with the difference in level between said reference signal and said data signal selected to be representative of a value to be converted; a generator means for generating a generator signal having a level controllably variable independently of said data signal levels and said reference lEvel; a comparator means for alternately comparing said generator signal level with said reference signal level and said generator signal level with said data signal level to alternately produce a first comparator output indicative of the difference between said generator signal level and said reference signal level and a second comparator output indicative of the difference between said generator signal level and said data signal level; and a means responsive to said comparator outputs for providing control signals to said comparator means to alternately vary said generator signal level to substantially match said reference signal level and to vary said generator signal level to substantially match said data signal level, and for providing an output representative of the difference between said generator signal level when matched to said reference signal level and when matched to said data signal level to thereby represent said value to be converted.
Claim 7
Dependent Claim
14 words
A system as defined in claim 4 in which said levels are frequency levels.
Claim 8
Dependent Claim
17 words
A system as defined in claim 4 in which said comparator means comprises digital difference counter means.
Claim 9
Dependent Claim
112 words
A value conversion system comprising: a means for producing an input signal having a reference frequency, and data frequencies differing from said reference frequency by amounts selected to be representative of a value to be converted; a signal generator means for generating an internal signal having a frequency controllably variable independently of said input signal frequencies; a comparator means for digitally counting the difference in cycles of said reference frequency and said internal signal frequency and for producing a comparator output indicative of said difference; and an integrating means responsive to said comparator output for controlling said signal generator means to change said internal signal frequency to substantially match said reference frequency.
Claim 10
Dependent Claim
112 words
A value conversion system comprising: a means for producing an input signal having a reference frequency, and data frequencies differing from said reference frequency by amounts selected to be representative of a value to be converted; a signal generator means for generating an internal signal having a frequency controllably variable independently of said input signal frequencies; a comparator means for digitally counting the difference in cycles of said reference frequency and said internal signal frequency and for producing a comparator output indicative of said difference; and an integrating means responsive to said comparator output for controlling said signal generator means to change said internal signal frequency to substantially match said reference frequency.
Claim 11
Dependent Claim
218 words
A data conversion system comprising: an input means for providing alternately a reference input signal having a frequency and a data input signal having a frequency differing from said reference signal frequency by an amount selected to represent a value to be converted; a signal generator means for generating an internal signal having a frequency controllably variable independently of said data signal and reference signal frequencies; a period difference counting comparator means for alternately comparing said internal signal frequency with said reference signal frequency and comparing said internal signal frequency with said data signal frequency to alternately provide a digital output indicative of the difference between said internal signal frequency and said reference signal frequency and a digital output indicative of the difference between said internal signal frequency and said data signal frequency; and an integrating means responsive to said comparator outputs for controlling said signal generator to alternately vary said internal signal frequency to substantially match said reference signal frequency and to vary said internal signal frequency to substantially match said data signal frequency, and for producing a digital output representative of the change of said internal signal frequency between its value when matched to said reference signal frequency and its value when matched to said data signal frequency to thereby represent said value to be converted.
Claim 12
Dependent Claim
218 words
A data conversion system comprising: an input means for providing alternately a reference input signal having a frequency and a data input signal having a frequency differing from said reference signal frequency by an amount selected to represent a value to be converted; a signal generator means for generating an internal signal having a frequency controllably variable independently of said data signal and reference signal frequencies; a period difference counting comparator means for alternately comparing said internal signal frequency with said reference signal frequency and comparing said internal signal frequency with said data signal frequency to alternately provide a digital output indicative of the difference between said internal signal frequency and said reference signal frequency and a digital output indicative of the difference between said internal signal frequency and said data signal frequency; and an integrating means responsive to said comparator outputs for controlling said signal generator to alternately vary said internal signal frequency to substantially match said reference signal frequency and to vary said internal signal frequency to substantially match said data signal frequency, and for producing a digital output representative of the change of said internal signal frequency between its value when matched to said reference signal frequency and its value when matched to said data signal frequency to thereby represent said value to be converted.
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) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |