Initial acquisition signal detection system for TDMA satellite communication
US4168398A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 8, 1977 |
| Grant date | Sep 18, 1979 |
| Priority date | — |
| Expiry date | Nov 8, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B7/2125
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A low level initial acquisition signal consisting of a continuous wave signal portion followed by a phase-modulated signal portion is transmitted via a satellite to a receiving station. The received CW signal is converted by a voltage-controlled variable frequency local oscillator to an intermediate frequency signal which is fed to a narrow passband filter. The local oscillator frequency is linearly swept, and the maximum signal passing through the filter during one sweep is detected. The local oscillator is then locked at the local frequency which produced the maximum signal, thereby effecting frequency acquisition. Next, the phase-modulated signal portion is multiplied by a phase-modulated signal output from a variable phase local signal generator. The phase of the local generator is also swept, and the maximum phase correlation signal passing through the band pass filter is again detected, and the phase of the generator output is corrected by the phase shift which produced the maximum phase correlation signal. This phase shift is used as a basis for determining the proper timing for acquisition of the correct time slot in the TDMA frame at the satellite for a transmitted data bu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.