Patent US5305347A successfully refreshed from Google Patents.
US5305347A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of detecting the frequency deviation in digital communication transmissions
Assignee: Airbus Defence and Space GmbH
•
Filing: 1991-09-03
•
Granted: 1994-04-19
•
Expires: 2011-09-03
Abstract
Abstract The invention discloses a method of measuring the rough frequency deviation in digital communication transmissions with echo propagation, particularly in the short-wave domain. A repeatedly transmitted PN sequence serves as the preamble of a data block. This PN sequence is compressed at the receiving end in matched filters provided in each one of a plurality of simultaneous, frequency offset Doppler channels. The Doppler channel having the greatest amplitude in the quadrature signal is selected for a determination of the rough frequency deviation. To detect a pattern in the preamble, the quadrature signals are examined for similarities by an amplitude comparison or in a cross-correlation process.
Inventors
- 👤 Hansjorg Roschmann
- 👤 Walter Theisges
- 👤 Manfred Zoberbier
- 👤 Achim Brakemeier
- 👤 Jurgen Lindner
- 👤 Ralf Esprester
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:41
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/01
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
135 words
A method of detecting a coarse frequency deviation of a digital communication transmission having echo propagation, wherein the transmission includes a plurality of data blocks where each data block includes a preamble of a repeated pseudo noise sequence comprising the steps of: applying the preamble of a data block to a plurality of simultaneous Doppler channels at a receiver, the plurality of simultaneous Doppler channels including at least one pair of simultaneous Doppler channels offset in frequency relative to a received frequency of the transmission by a predetermined positive and predetermined negative amount, respectively; compressing the preamble in each simultaneous Doppler channel to produce a quadrature signal associated with each simultaneous Doppler channel; and determining the coarse frequency deviation of the transmission based on an amplitude of a quadrature signal associated with a Doppler channel.
Claim 2
Independent Claim
135 words
A method of detecting a coarse frequency deviation of a digital communication transmission having echo propagation, wherein the transmission includes a plurality of data blocks where each data block includes a preamble of a repeated pseudo noise sequence comprising the steps of: applying the preamble of a data block to a plurality of simultaneous Doppler channels at a receiver, the plurality of simultaneous Doppler channels including at least one pair of simultaneous Doppler channels offset in frequency relative to a received frequency of the transmission by a predetermined positive and predetermined negative amount, respectively; compressing the preamble in each simultaneous Doppler channel to produce a quadrature signal associated with each simultaneous Doppler channel; and determining the coarse frequency deviation of the transmission based on an amplitude of a quadrature signal associated with a Doppler channel.
Claim 3
Dependent Claim
45 words
A method according to claim 1, wherein the plurality of simultaneous Doppler channels includes three simultaneous Doppler channels with two simultaneous Doppler channels being shifted in frequency by a predetermined positive and a predetermined negative amount, respectively, relative to a received frequency of the transmission.
Claim 4
Dependent Claim
40 words
A method according to one of claim 1, wherein the step of determining the coarse frequency deviation includes averaging amplitudes of quadrature signals over a predetermined time interval corresponding to a maximum channel burst response duration associated with the transmission.
Claim 5
Dependent Claim
44 words
A method according to claim 1, wherein the frequency offset between the at least one pair of simultaneous Doppler channels relative to the received frequency of the transmission is substantially equal to an inverse of a double pseudo noise sequence duration T PN .
Claim 6
Dependent Claim
40 words
A method according to claim 1, further comprising the step of determining a fine frequency deviation of the transmission based on a phase shift from pseudo noise sequence to pseudo noise sequence of the quadrature signal having a greatest amplitude.
Claim 7
Dependent Claim
28 words
A method according to claim 1, further comprising the step of detecting patterns of the preamble based on a similarity between pseudo noise sequences in a quadrature signal.
Claim 8
Dependent Claim
18 words
A method according to claim 6, wherein the similarity is related to a cross-correlation on pseudo noise sequences.
Claim 9
Dependent Claim
20 words
A method according to claim 6, wherein the similarity is related to an amplitude comparison between successive pseudo noise sequences.
Claim 10
Dependent Claim
35 words
A method according to claim 8, the amplitude comparison is based on a similarity of a plurality of averages formed over a plurality of signal amplitudes related to a length of the pseudo noise sequence.
References Cited (Backward Citations)
US3694757A
Cited
DE2822874A1
Cited
EP0164108A2
Cited
GB2161344A
Cited
US5090023A
Cited
EP0387720A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-04-18 | 1997-10-18 | 1998-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-04-18 | 2001-10-18 | 2002-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-04-18 | 2005-10-18 | 2006-04-19 | $7700.00 | Window Closed / Lapsed |