US4587661A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for synchronizing spread spectrum transmissions from small earth stations used for satellite transmission
Assignee: RCA Corp
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Filing: 1983-03-04
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Granted: 1986-05-06
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Expires: 2003-03-04
Abstract
Abstract A low-power, spread spectrum synchronized communication system employing a satellite which continuously and iteratively re-transmits a PRS signal PRS m from a master earth station having a chip rate C m and a bit rate B m and comprising a plurality of ground stations each including a transmitter for transmitting a first PRS signal (PRS G ) unique thereto and having a first chip rate C G and a first bit rate B G and a receiver for receiving and identifying PRS G after being returned by the satellite as PRS Gr with a chip rate C Gr and a bit rate B Gr . Also provided is a phase difference detector responsive to C m and C Gr to periodically produce a signal representative of the change of phase difference thereof and a frequency changing circuit responsive to such signal to change the chip rate C Gr by an amount which will cause the phase of C Gr to approach the phase of C m at a given rate.
Inventors
- 👤 Leonard N. Schiff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:19
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/69; H04B1/707; H04B7/00; H04B7/14; H04B7/15; H04B7/204; H04B7/216; Y; Y02; Y02D; Y02D30/00; Y02D30/70
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
198 words
A communication system, employing a satellite which continuously and interatively re-transmits a pseudo-random sequence signal PRS m having a chip rate C m and a bit rate B m , said system comprising: a plurality of ground stations each having a transmitter and a receiver; means for transmitting a first pseudo-random sequence signal PRS G having a first chip rate C G and a first bit rate B G from at least one ground station to said satellite; means at said at least one ground station for receiving and identifying PRS G after being returned by said satellite as PRS Gr with a chip rate C Gr ; means at said at least one ground station for receiving and identifying PRS m ; means responsive to the phase difference between C m and C Gr to produce a signal value representative thereof every time period τ; and means responsive to said signal value to change the chip rate C Gr by an amount which will cause the phase of C Gr to approach the phase of C m at a rate which will approximate the phase of C m at the end of the next time period τ.
Claim 2
Dependent Claim
198 words
A communication system, employing a satellite which continuously and interatively re-transmits a pseudo-random sequence signal PRS m having a chip rate C m and a bit rate B m , said system comprising: a plurality of ground stations each having a transmitter and a receiver; means for transmitting a first pseudo-random sequence signal PRS G having a first chip rate C G and a first bit rate B G from at least one ground station to said satellite; means at said at least one ground station for receiving and identifying PRS G after being returned by said satellite as PRS Gr with a chip rate C Gr ; means at said at least one ground station for receiving and identifying PRS m ; means responsive to the phase difference between C m and C Gr to produce a signal value representative thereof every time period τ; and means responsive to said signal value to change the chip rate C Gr by an amount which will cause the phase of C Gr to approach the phase of C m at a rate which will approximate the phase of C m at the end of the next time period τ.
Claim 3
Dependent Claim
145 words
A communication system employing a satellite which continuously and iteratively re-transmits a pseudo-random sequence signal having a chip rate C m and a bite rate B m , said system comprising: a plurality of ground stations each comprising: means for transmitting a first pseudo-random sequence signal PRS G unique thereto and have a first chip rate C G and a first bit rate B C and for receiving and identifying PRS G after being returned by said satellite as PRS Gr with a chip rate C Gr and a bit rate B Gr ; means responsive to C m and C Gr to periodically produce a signal representative of the phase difference therebetween; and means responsive to said signal to change the phase of C G in a direction which will cause the phase of C Gr to approach the phase of C m .
Claim 4
Dependent Claim
145 words
A communication system employing a satellite which continuously and iteratively re-transmits a pseudo-random sequence signal having a chip rate C m and a bite rate B m , said system comprising: a plurality of ground stations each comprising: means for transmitting a first pseudo-random sequence signal PRS G unique thereto and have a first chip rate C G and a first bit rate B C and for receiving and identifying PRS G after being returned by said satellite as PRS Gr with a chip rate C Gr and a bit rate B Gr ; means responsive to C m and C Gr to periodically produce a signal representative of the phase difference therebetween; and means responsive to said signal to change the phase of C G in a direction which will cause the phase of C Gr to approach the phase of C m .
Claim 5
Dependent Claim
204 words
A receiver in a communications system employing a satellite for receiving and retransmitting pseudo random sequence (PRS) signals from said receiver and having logic for iteratively transmitting master PRS signal PRS m having a chip rate C m and a bit rate B m , said receiver comprising: means for transmitting a first PRS signal PRS G having a first chip rate C G and a first bit rate B G ; means for receiving and identifying PRS G after being returned by said satellite as PRS Gr having a chip rate C Gr and a bit rate B Gr ; means for receiving and identifying PRS m ; means responsive to C Gr and C m to produce a signal representative of the phase difference therebetween every time period τ; means responsive to successive phase differences between C Gr and C m to determine the frequency difference between C Gr and C m ; and means responsive to said frequency difference to change the chip rate C Gr by an amount which will cause the phase of C Gr to change by an amount which will cause the phase of C Gr to approach the phase of C m at a given rate.
Claim 6
Dependent Claim
204 words
A receiver in a communications system employing a satellite for receiving and retransmitting pseudo random sequence (PRS) signals from said receiver and having logic for iteratively transmitting master PRS signal PRS m having a chip rate C m and a bit rate B m , said receiver comprising: means for transmitting a first PRS signal PRS G having a first chip rate C G and a first bit rate B G ; means for receiving and identifying PRS G after being returned by said satellite as PRS Gr having a chip rate C Gr and a bit rate B Gr ; means for receiving and identifying PRS m ; means responsive to C Gr and C m to produce a signal representative of the phase difference therebetween every time period τ; means responsive to successive phase differences between C Gr and C m to determine the frequency difference between C Gr and C m ; and means responsive to said frequency difference to change the chip rate C Gr by an amount which will cause the phase of C Gr to change by an amount which will cause the phase of C Gr to approach the phase of C m at a given rate.
Claim 7
Dependent Claim
208 words
In a commmunication system employing at least one ground station and a satellite having a transponder for receiving and re-transmitting pseudo random sequence (PRS) signals transmitted from said at least one ground station, and logic for iteratively transmitting a master PRS signal PRS m having a chip rate C m and a bit rate B m , a method for synchronizing the chip and bit rate of the PRS m and the PRS signal retransmitted at said satellite and comprising the steps of: transmitting from said at least one ground station a first PRS signal PRS G having a first chip rate C G and a first bit rate B G ; receiving and identifying PRS G after being returned by said satellite as PRS Gr with a chip rate C Gr and a bit rate B Gr ; receiving and identifying PRS m at said at least one ground station; comparing the phases of C m and C Gr to produce a signal representative of the difference therebetween every time period τ; and changing the chip rate C Gr in response to said signal by an amount and in a direction which will cause the phase of C Gr to appraoch the phase of C m .
Claim 8
Dependent Claim
208 words
In a commmunication system employing at least one ground station and a satellite having a transponder for receiving and re-transmitting pseudo random sequence (PRS) signals transmitted from said at least one ground station, and logic for iteratively transmitting a master PRS signal PRS m having a chip rate C m and a bit rate B m , a method for synchronizing the chip and bit rate of the PRS m and the PRS signal retransmitted at said satellite and comprising the steps of: transmitting from said at least one ground station a first PRS signal PRS G having a first chip rate C G and a first bit rate B G ; receiving and identifying PRS G after being returned by said satellite as PRS Gr with a chip rate C Gr and a bit rate B Gr ; receiving and identifying PRS m at said at least one ground station; comparing the phases of C m and C Gr to produce a signal representative of the difference therebetween every time period τ; and changing the chip rate C Gr in response to said signal by an amount and in a direction which will cause the phase of C Gr to appraoch the phase of C m .
Claim 9
Dependent Claim
72 words
A commmuncation system as in claim 4 in which the step of comparing the phases of C m and C Gr comprises the steps of: comparing C m and C Gr every time period τ to periodically produce a signal representative of the phase difference thereof; and computing the frequency difference between C Gr and C m by comparing the differences between successive phase differences of C Gr and C m .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-05 | 1989-11-04 | 1990-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-05 | 1993-11-04 | 1994-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-05 | 1997-11-04 | 1998-05-06 | $7700.00 | Window Closed / Lapsed |