Frequency synchronized bidirectional radio system
US5604768A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 21, 1994 |
| Grant date | Feb 18, 1997 |
| Priority date | — |
| Expiry date | Dec 21, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2027/0057
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A bidirectional radio system for low-cost high-throughput accumulation of data from a large number of site units. Frequency synchronization is achieved at low cost by transmitting a high accuracy carrier and clock signal at a base station, and using receiving circuitry at remote stations to extract the base clock signal and base carrier frequency and a phase-lock loop to stabilize the remote station carriers. A burst demodulator at a base station receiver can decode a short remote station response by scaling the response with the phase and amplitude of an initial segment of the response. The burst demodulator may continuously update the decoding threshold based on a comparison of the signal amplitude and the current value of the decoding threshold. In an alternate embodiment, the carrier synthesizer is not part of a phase-lock loop, but the transmitted signal is rotated by a phase proportional to a frequency error to provide an accurate carrier frequency. In yet another alternate embodiment only a frequency-control loop is implemented, and again the transmitted signal is rotated by a phase ramp proportional to a frequency error to provide an accurate carrier frequency. In this embo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.