Frequency synchronizing system for satellite communication
US4019138A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 19, 1976 |
| Grant date | Apr 19, 1977 |
| Priority date | — |
| Expiry date | Feb 19, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B7/01
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A frequency synchronizing system for satellite communication, in which a reference frequency coming from a communications satellite is received by a receiving circuit. A first frequency variable oscillator is provided for generating a transmission signal. A second receiving circuit is provided for receiving through the communications satellite the transmission signal which is the output from the first frequency variable oscillator, A first frequency control circuit is provided for controlling the first frequency variable oscillator for making the frequencies of the outputs from the first and second receiving circuits equal to each other. A second frequency variable oscillator is provided for generating a signal of a frequency twice as high as the reference frequency. A frequency converter is provided for mixing the output from the first or second receiving circuit with the output from the second frequency variable oscillator to produce a signal of a difference frequency substantially equal to that of the transmission signal. A phase detector detects the phase difference between the transmission signal and the output from the frequency converter. A frequency control circuit is provi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.