US3699254A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Code tone pulse train data transmitting and receiving system using sine wave gating
Assignee: International Data Systems LLC
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Filing: 1969-11-17
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Granted: 1972-10-17
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Expires: 1989-11-17
Abstract
Abstract Method and apparatus for transmitting data through the medium of ordinary telephone lines and handsets. Character information is generated in the form of gated sine wave tone bursts of a fixed audio frequency compatible with the telephone system, wherein the character information is contained in the number of continuous sine wave cycles in each tone burst. The sharp rise and decay times normally associated with pulse transmission, and consequent ringing and interference with reserved frequency areas, are avoided by substantially zero crossover initiation and termination of each tone burst, and PDM distortion is minimized by a combination of partial modulation, substantial on time-tooff time, and optimum frequency selection for harmonic and subharmonic rejection by telephone system rolloff.
Inventors
- 👤 James C Nailen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:03
CPC Classifications
H; H04; H04L; H04L27/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
175 words
The method of transmitting data which comprises generating a continuous sine wave electrical signal of substantially constant frequency, gating said sine wave signal to produce a plurality of successive bursts thereof, said gating determining the number of sine wave cycles in each of said bursts, and the number of cycle intervals between said successive bursts, each of said sine wave bursts designating assigned character information according to the number of sine wave cycles contained therein, converting said tone bursts after the transmission thereof to a plurality of pulse trains corresponding to the respective tone bursts, each of said pulse trains having the same number of pulses therein as sine wave cycles in its respective tone burst, sampling the pulses in each of said pulse trains and generating a free running pulse string substantially identical to each of said pulse trains, comparing each of said pulse trains with its respective said pulse string, and initiating a termination signal with the first pulse of said free running pulse string after the end of the respective pulse train.
Claim 2
Independent Claim
175 words
The method of transmitting data which comprises generating a continuous sine wave electrical signal of substantially constant frequency, gating said sine wave signal to produce a plurality of successive bursts thereof, said gating determining the number of sine wave cycles in each of said bursts, and the number of cycle intervals between said successive bursts, each of said sine wave bursts designating assigned character information according to the number of sine wave cycles contained therein, converting said tone bursts after the transmission thereof to a plurality of pulse trains corresponding to the respective tone bursts, each of said pulse trains having the same number of pulses therein as sine wave cycles in its respective tone burst, sampling the pulses in each of said pulse trains and generating a free running pulse string substantially identical to each of said pulse trains, comparing each of said pulse trains with its respective said pulse string, and initiating a termination signal with the first pulse of said free running pulse string after the end of the respective pulse train.
Claim 3
Dependent Claim
232 words
Data transmitting and receiving apparatus which comprises a transmitter comprising circuit means for generating a continuous sine wave electrical signal, gating circuit means associated with the output of said sine wave generating circuit means, and data input means operatively connected to said gating circuit means to cause the latter to gate said sine wave signal to produce a plurality of successive bursts thereof designating assigned character information according to the number of sine wave cycles contained therein; and a receiver comprising input means for receiving said successive bursts of sine wave signal, pulse generating means connected to said input means and responsive to each sine wave cycle in said bursts of sine wave signal to generate a plurality of successive trains of pulses corresponding to said successive bursts of said sine wave signal, free running pulse producing means connected to said pulse generating means and synchronized therewith to produce an output of free running pulses that are substantially identical to the pulses from said pulse generating means, and comparator circuit means connected to the outputs of said pulse generating means and said free running pulse producing means, said comparator circuit means having an output responsive to the first pulse from said free running pulse producing means that is not accompanied by a pulse from said pulse generating means whereby to indicate the end of a pulse train from sAid pulse generating means.
Claim 4
Dependent Claim
232 words
Data transmitting and receiving apparatus which comprises a transmitter comprising circuit means for generating a continuous sine wave electrical signal, gating circuit means associated with the output of said sine wave generating circuit means, and data input means operatively connected to said gating circuit means to cause the latter to gate said sine wave signal to produce a plurality of successive bursts thereof designating assigned character information according to the number of sine wave cycles contained therein; and a receiver comprising input means for receiving said successive bursts of sine wave signal, pulse generating means connected to said input means and responsive to each sine wave cycle in said bursts of sine wave signal to generate a plurality of successive trains of pulses corresponding to said successive bursts of said sine wave signal, free running pulse producing means connected to said pulse generating means and synchronized therewith to produce an output of free running pulses that are substantially identical to the pulses from said pulse generating means, and comparator circuit means connected to the outputs of said pulse generating means and said free running pulse producing means, said comparator circuit means having an output responsive to the first pulse from said free running pulse producing means that is not accompanied by a pulse from said pulse generating means whereby to indicate the end of a pulse train from sAid pulse generating means.
Claim 5
Dependent Claim
19 words
The method of claim 1, which includes using said termination signal to turn off said free running pulse string.
Claim 6
Dependent Claim
49 words
Apparatus as defined in claim 2, which includes a feedback connection from said comparator circuit output to said free running pulse producing means for turning off said pulse producing means in response to the first pulse therefrom that is not accompanied by a pulse from said pulse generating means.
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) | 1975-10-17 | 1976-04-17 | 1976-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-17 | 1980-04-17 | 1980-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-17 | 1984-04-17 | 1984-10-17 | $7700.00 | Window Closed / Lapsed |