Patent US3739296A successfully refreshed from Google Patents.
Patent US2802546A successfully refreshed from Google Patents.
Patent US3593256A successfully refreshed from Google Patents.
US3593256A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Doppler correction technique
Assignee: United States Department of the Navy
•
Filing: 1969-10-22
•
Granted: 1971-07-13
•
Expires: 1989-10-22
Abstract
Abstract Method and means for complete correction of Doppler shift in a transmitted spectrum of individual frequencies, or tones, constituting a multitone, coded pulse system in which the lowest (reference) and highest frequencies and the bandwidth are known and enclose an information band of frequencies. The upper and lower half-bands of the received signal are filtered out and mixed to provide the difference frequencies, one of which is a unique frequency corresponding to the spectrum bandwidth. This is filtered out and multiplied by a fixed factor to provide the zero-Doppler reference frequency. The latter is mixed with the information band, which has been filtered from the input signal, and the result is a signal which comprises the information band Doppler-corrected for the reference frequency. The signal corresponding to the spectrum bandwidth is also sent through means which senses the amount of Doppler-shift it has undergone, selects an inverse multiplying factor in accordance with this amount of shift and multiplies the reference-frequency-corrected information band, thereby correcting it for the Doppler-stretch the received information band has undergone. The information band is now completely Doppler-corrected and is divided by a zeroDoppler correction factor to correct the spectral spread introduced by the previous multiplication by said inverse multiplying factor.
Inventors
- 👤 Edmund C Gannon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:09
CPC Classifications
G; G01; G01S; G01S1/00; G01S1/72; G01S1/725; H; H04; H04B; H04B11/00; H04B7/00; H04B7/01; Y; Y10; Y10S; Y10S367/00; Y10S367/904
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
220 words
A method for correcting Doppler-shift effects in a transmitted signal spectrum consisting of plurality of tones of discrete frequency including a zero-Doppler reference frequency, a zero-Doppler upper-limit frequency and a variable set of information band frequencies enclosed therebetween, the enclosing frequencies and the frequency difference between them, or bandwidth, being known, said reference frequency being an integral number (M) times the bandwidth, said method comprising the steps of: separating the received signal into an upper and lower halfband; mixing the half-band signals together to obtain the difference frequencies, one of which is a frequency which has the same value as the Doppler-shifted bandwidth; filtering out the Doppler-shifted bandwidth frequency; multiplying the bandwidth frequency by said integral number, M, to obtain the Doppler-shifted reference frequency; sensing the amount of Doppler-shift in the bandwidth frequency and obtaining a variable multiplying factor which is in inverse ratio to the amount of Doppler-shift; filtering out of the received signal the Doppler-shifted information band frequencies; mixing said information band frequencies with said Dopplershifted reference frequency and filtering the resultant signal to obtain a new set of information band frequencies Dopplercorrected for the reference frequency; and multiplying the new set of information band frequencies by said variable multiplying factor to obtain a set of information band frequencies which is completely Doppler-corrected but has a spectrum spread.
Claim 2
Independent Claim
220 words
A method for correcting Doppler-shift effects in a transmitted signal spectrum consisting of plurality of tones of discrete frequency including a zero-Doppler reference frequency, a zero-Doppler upper-limit frequency and a variable set of information band frequencies enclosed therebetween, the enclosing frequencies and the frequency difference between them, or bandwidth, being known, said reference frequency being an integral number (M) times the bandwidth, said method comprising the steps of: separating the received signal into an upper and lower halfband; mixing the half-band signals together to obtain the difference frequencies, one of which is a frequency which has the same value as the Doppler-shifted bandwidth; filtering out the Doppler-shifted bandwidth frequency; multiplying the bandwidth frequency by said integral number, M, to obtain the Doppler-shifted reference frequency; sensing the amount of Doppler-shift in the bandwidth frequency and obtaining a variable multiplying factor which is in inverse ratio to the amount of Doppler-shift; filtering out of the received signal the Doppler-shifted information band frequencies; mixing said information band frequencies with said Dopplershifted reference frequency and filtering the resultant signal to obtain a new set of information band frequencies Dopplercorrected for the reference frequency; and multiplying the new set of information band frequencies by said variable multiplying factor to obtain a set of information band frequencies which is completely Doppler-corrected but has a spectrum spread.
Claim 3
Dependent Claim
30 words
A method as in claim 1, further including the step of: dividing by said zero-Doppler multiplication factor said completely corrected set of information band frequencies to correct the spectrum spread.
Claim 4
Independent Claim
263 words
A method for correcting Doppler-shift effects in a transmitted signal spectrum consisting of a plurality of tones of discrete frequency including a zero-Doppler reference frequency (fr), a zero-Doppler upper-limit frequency (fo) and a varIable set of information band frequencies enclosed therebetween, the enclosing frequencies being known and therefore the zero-Doppler bandwidth, Delta f fo-fr, being known, said reference frequency being a known integral number (M) times the bandwidth, namely, fr M ( Delta f), said method comprising the steps of: separating the received signal into an upper and a lower half-band; mixing the half-band signals together to obtain the difference frequencies, one of which is a tone having a frequency, Delta f'', the same value as the Doppler-shifted bandwidth; filtering out the Doppler-shifted bandwidth frequency; multiplying the bandwidth frequency by said integral number, M, to obtain the Doppler-shifted reference frequency, fr''; sensing the amount of Doppler-shift in the bandwidth frequency and obtaining a variable multiplying factor, m, which is in inverse ratio to the amount of Doppler-shift and is in accordance with the formula m1 ( Delta f'') m ( Delta f), where m is a preselected zero-Doppler multiplication factor; filtering out of the original received signal the Doppler-shifted information band frequencies; mixing said information band frequencies with said reference frequency and filtering the resultant signal to obtain a new set of information band frequencies Doppler-corrected for the reference frequency; and multiplying the new set of information band frequencies by said variable multiplying factor, m1 , to obtain a set of information band frequencies which is completely Doppler-corrected but has a spectrum spread.
Claim 5
Independent Claim
263 words
A method for correcting Doppler-shift effects in a transmitted signal spectrum consisting of a plurality of tones of discrete frequency including a zero-Doppler reference frequency (fr), a zero-Doppler upper-limit frequency (fo) and a varIable set of information band frequencies enclosed therebetween, the enclosing frequencies being known and therefore the zero-Doppler bandwidth, Delta f fo-fr, being known, said reference frequency being a known integral number (M) times the bandwidth, namely, fr M ( Delta f), said method comprising the steps of: separating the received signal into an upper and a lower half-band; mixing the half-band signals together to obtain the difference frequencies, one of which is a tone having a frequency, Delta f'', the same value as the Doppler-shifted bandwidth; filtering out the Doppler-shifted bandwidth frequency; multiplying the bandwidth frequency by said integral number, M, to obtain the Doppler-shifted reference frequency, fr''; sensing the amount of Doppler-shift in the bandwidth frequency and obtaining a variable multiplying factor, m, which is in inverse ratio to the amount of Doppler-shift and is in accordance with the formula m1 ( Delta f'') m ( Delta f), where m is a preselected zero-Doppler multiplication factor; filtering out of the original received signal the Doppler-shifted information band frequencies; mixing said information band frequencies with said reference frequency and filtering the resultant signal to obtain a new set of information band frequencies Doppler-corrected for the reference frequency; and multiplying the new set of information band frequencies by said variable multiplying factor, m1 , to obtain a set of information band frequencies which is completely Doppler-corrected but has a spectrum spread.
Claim 6
Dependent Claim
31 words
A method as in claim 3, further including the step of: dividing by said zero-Doppler multiplication factor, m, said completely corrected set of information band frequencies to correct the spectrum spread.
Claim 7
Dependent Claim
272 words
A means for correcting Doppler-shift effects in a transmitted signal spectrum consisting of a plurality of tones of discrete frequency including a zero-Doppler reference frequency, a zero-Doppler upper-limit frequency and a variable set of information band frequencies enclosed therebetween, the enclosing frequencies and the frequency difference between them, or bandwidth, being known, said reference frequency being an integral number (M) times the bandwidth, said means comprising the steps of: means for separating the received signal into an upper and a lower half-band; means for mixing the half-band signals together to obtain the difference frequencies, one of which is a frequency which has the same value as the Doppler-shifted bandwidth; means for filtering out the Doppler-shifted bandwidth frequency, the bandwidth of said filtering means being approximately equal to plus or minus the maximum expected Doppler shift of the transmitted singal''s zero-Doppler bandwidth and the center frequency being equal to said zero-Doppler bandwidth; means for multiplying the bandwidth frequency by said integral number, M, to obtain the Doppler-shifted reference frequency; means for sensing the amount of Doppler-shift in the bandwidth frequency and obtaining a variable multiplying factor which is in inverse ratio to the amount of Doppler-shift; means for filtering out of the received signal the Doppler-shifted information band frequencies; means for mixing said information band frequencies with said Doppler-shifted reference frequency and filtering the resultant signal to obtain a new set of information band frequencies Doppler-corrected for the reference frequency; and means for multiplying the new set of information band frequencies by said variable multiplying factor to obtain a set of information band frequencies which is completely Doppler-corrected but has a spectrum spread.
Claim 8
Dependent Claim
272 words
A means for correcting Doppler-shift effects in a transmitted signal spectrum consisting of a plurality of tones of discrete frequency including a zero-Doppler reference frequency, a zero-Doppler upper-limit frequency and a variable set of information band frequencies enclosed therebetween, the enclosing frequencies and the frequency difference between them, or bandwidth, being known, said reference frequency being an integral number (M) times the bandwidth, said means comprising the steps of: means for separating the received signal into an upper and a lower half-band; means for mixing the half-band signals together to obtain the difference frequencies, one of which is a frequency which has the same value as the Doppler-shifted bandwidth; means for filtering out the Doppler-shifted bandwidth frequency, the bandwidth of said filtering means being approximately equal to plus or minus the maximum expected Doppler shift of the transmitted singal''s zero-Doppler bandwidth and the center frequency being equal to said zero-Doppler bandwidth; means for multiplying the bandwidth frequency by said integral number, M, to obtain the Doppler-shifted reference frequency; means for sensing the amount of Doppler-shift in the bandwidth frequency and obtaining a variable multiplying factor which is in inverse ratio to the amount of Doppler-shift; means for filtering out of the received signal the Doppler-shifted information band frequencies; means for mixing said information band frequencies with said Doppler-shifted reference frequency and filtering the resultant signal to obtain a new set of information band frequencies Doppler-corrected for the reference frequency; and means for multiplying the new set of information band frequencies by said variable multiplying factor to obtain a set of information band frequencies which is completely Doppler-corrected but has a spectrum spread.
Claim 9
Dependent Claim
29 words
A means as in claim 5, further including: means for dividing by said zero-Doppler multiplication factor saiD completely corrected set of information band frequencies to correct the spectrum spread.
Claim 10
Dependent Claim
319 words
A means for correcting Doppler-shift effects in a transmitted signal spectrum consisting of a plurality of tones of discrete frequency including a zero-Doppler reference frequency (fr), a zero-Doppler upper-limit frequency (fo) and a variable set of information band frequencies enclosed therebetween, the enclosing frequencies being known and therefore the zero-Doppler bandwidth, Delta f fo-fr, being known, said reference frequency being a known integral number (M) times the bandwidth, namely, fr M( Delta f), said means comprising the steps of: means for separating the received signal into an upper and a lower half-band; means for mixing the half-band signals together to obtain the difference frequencies, one of which is a tone having a frequency, Delta f'', the same value as the Doppler-shifted bandwidth; means for filtering out the Doppler-shifted bandwidth frequency, the center frequency of said filtering means being equal to Delta f, and the bandwidth of said filtering means being equal to + or - maximum expected Doppler-shift of Delta f, that is, + or - ( Delta f''max- Delta f); means for multiplying the bandwidth frequency by said integral number, M, to obtain the Doppler-shifted reference frequency, fr''; means for sensing the amount of Doppler-shift in the bandwidth frequency and obtaining a variable multiplying factor, m, which is in inverse ratio to the amount of Doppler-shift and is in accordance with the formula m1 ( Delta f'') m ( Delta f), where m is a preselected zero-Doppler multiplication factor; means for filtering out of the original received signal the Doppler-shifted information band frequencies; means for mixing said information band frequencies with said reference frequency and filtering the resultant signal to obtain a new set of information band frequencies Doppler-corrected for the reference frequency; and means for multiplying the new set of information band frequencies by said variable multiplying factor, m1 , to obtain a set of information band frequencies which is completely Doppler-corrected but has a spectrum spread.
Claim 11
Dependent Claim
319 words
A means for correcting Doppler-shift effects in a transmitted signal spectrum consisting of a plurality of tones of discrete frequency including a zero-Doppler reference frequency (fr), a zero-Doppler upper-limit frequency (fo) and a variable set of information band frequencies enclosed therebetween, the enclosing frequencies being known and therefore the zero-Doppler bandwidth, Delta f fo-fr, being known, said reference frequency being a known integral number (M) times the bandwidth, namely, fr M( Delta f), said means comprising the steps of: means for separating the received signal into an upper and a lower half-band; means for mixing the half-band signals together to obtain the difference frequencies, one of which is a tone having a frequency, Delta f'', the same value as the Doppler-shifted bandwidth; means for filtering out the Doppler-shifted bandwidth frequency, the center frequency of said filtering means being equal to Delta f, and the bandwidth of said filtering means being equal to + or - maximum expected Doppler-shift of Delta f, that is, + or - ( Delta f''max- Delta f); means for multiplying the bandwidth frequency by said integral number, M, to obtain the Doppler-shifted reference frequency, fr''; means for sensing the amount of Doppler-shift in the bandwidth frequency and obtaining a variable multiplying factor, m, which is in inverse ratio to the amount of Doppler-shift and is in accordance with the formula m1 ( Delta f'') m ( Delta f), where m is a preselected zero-Doppler multiplication factor; means for filtering out of the original received signal the Doppler-shifted information band frequencies; means for mixing said information band frequencies with said reference frequency and filtering the resultant signal to obtain a new set of information band frequencies Doppler-corrected for the reference frequency; and means for multiplying the new set of information band frequencies by said variable multiplying factor, m1 , to obtain a set of information band frequencies which is completely Doppler-corrected but has a spectrum spread.
Claim 12
Dependent Claim
30 words
A means as in claim 7, further including: means for dividing by said zero-Doppler multiplication factor, m, said completely corrected set of information band frequencies to correct the spectrum spread.
References Cited (Backward Citations)
US3325736A
Cited
US3341808A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-12 | 1975-01-11 | 1975-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-12 | 1979-01-11 | 1979-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-12 | 1983-01-11 | 1983-07-13 | $7700.00 | Window Closed / Lapsed |