US3846583A
Expired / Lapsed
US
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Digital communication systems
Assignee: Post Office
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Filing: 1972-10-18
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Granted: 1974-11-05
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Expires: 1992-10-18
Abstract
Abstract The invention is particularly applicable to line telephony and relates to a method and apparatus for converting an isochronous baseband data signal into a diphase signal and vice versa. The diphase transmission is considered as a phase modulation or double-sideband suppressed-carrier in which the modulating signal switches the phase of a carrier whose fundamental frequency in hertz is the same as the modulation rate in bauds. The resulting modulated signal contains fold-over components which are used to advantage by introducing a 90* phase shift between the carrier and base band signals to reduce the line signal level at low frequencies where the line distortion is most severe and enhance the signal level at high frequencies where the attenuation is greatest. The need for line equalisation is therefore reduced.
Inventors
- 👤 R Boulter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:40
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/38; H04L25/40; H04L25/49; H04L25/4904
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
98 words
A method of converting an isochronous Base band data signal into a diphase signal including the steps of applying an unfiltered isochronous base band data signal and a carrier signal having a substantially square-waveform, and a frequency equal to the reciprocal of the duration of one element of the base band data signal to respective inputs of balanced modulating means and shifting the phase relation between the base band data signal and the carrier so that at the modulating means inputs, zerocrossings of the carrier occur one-quarter of a cycle before transitions of the base band data signal.
Claim 2
Independent Claim
98 words
A method of converting an isochronous Base band data signal into a diphase signal including the steps of applying an unfiltered isochronous base band data signal and a carrier signal having a substantially square-waveform, and a frequency equal to the reciprocal of the duration of one element of the base band data signal to respective inputs of balanced modulating means and shifting the phase relation between the base band data signal and the carrier so that at the modulating means inputs, zerocrossings of the carrier occur one-quarter of a cycle before transitions of the base band data signal.
Claim 3
Independent Claim
101 words
A method of converting an isochronous base band data signal into a diphase signal including the steps of applying an unfiltered isochronous base band data signal and a carrier having a substantially square-waveform and a frequency equal to the reciprocal of the duration of one element of the base band data signal to respective inputs of a modulo 2 adder means and shifting the phase relation between the base band data signal and the carrier so that at the modulo 2 adder means inputs, zero-crossings of the carrier occur one-quarter of a cycle before transitions of the base band data signal.
Claim 4
Independent Claim
101 words
A method of converting an isochronous base band data signal into a diphase signal including the steps of applying an unfiltered isochronous base band data signal and a carrier having a substantially square-waveform and a frequency equal to the reciprocal of the duration of one element of the base band data signal to respective inputs of a modulo 2 adder means and shifting the phase relation between the base band data signal and the carrier so that at the modulo 2 adder means inputs, zero-crossings of the carrier occur one-quarter of a cycle before transitions of the base band data signal.
Claim 5
Dependent Claim
120 words
A base band to diphase converter comprising balanced modulating means arranged to receive an unfiltered isochronous base band data signal as a first input and a carrier signal having a substantially square-waveform and of frequency equal to the reciprocal of the duration of one element of the base band data signal as a second input so as to generate the diphase signal at the output of modulating means and delay means connected to receive said square-wave carrier signal prior to application as said second input to cause zero-crossings of the carrier signal at the second input of the modulating means to occur one-quarter of a cycle before transitions of the data signal at the first input of the modulating means.
Claim 6
Dependent Claim
120 words
A base band to diphase converter comprising balanced modulating means arranged to receive an unfiltered isochronous base band data signal as a first input and a carrier signal having a substantially square-waveform and of frequency equal to the reciprocal of the duration of one element of the base band data signal as a second input so as to generate the diphase signal at the output of modulating means and delay means connected to receive said square-wave carrier signal prior to application as said second input to cause zero-crossings of the carrier signal at the second input of the modulating means to occur one-quarter of a cycle before transitions of the data signal at the first input of the modulating means.
Claim 7
Dependent Claim
119 words
A base band to diphase converter comprising a modulo-2 adder arranged to receive an unfiltered isochronous base band data signal as a first input and a carrier signal having a substantially square-waveform of frequency equal to the reciprocal of the duration of one element of base band data signal as a second input so as to generate a diphase signal at the output of the modulo-2 adder and delay means connected to receive said square-wave carrier signal prior to application as said second input to cause zero-crossings of the carrier signal at the second input of the modulo-2 adder to occur one-quarter of a cycle before transitions of the data signal at the first input of the modulo-2 adder.
Claim 8
Dependent Claim
119 words
A base band to diphase converter comprising a modulo-2 adder arranged to receive an unfiltered isochronous base band data signal as a first input and a carrier signal having a substantially square-waveform of frequency equal to the reciprocal of the duration of one element of base band data signal as a second input so as to generate a diphase signal at the output of the modulo-2 adder and delay means connected to receive said square-wave carrier signal prior to application as said second input to cause zero-crossings of the carrier signal at the second input of the modulo-2 adder to occur one-quarter of a cycle before transitions of the data signal at the first input of the modulo-2 adder.
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) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |