Swept-carrier transmission system adapted for use in process control systems
US4209750A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 19, 1978 |
| Grant date | Jun 24, 1980 |
| Priority date | — |
| Expiry date | Jun 19, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/103
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A data transmission system comprising a transmitter producing a high-frequency carrier modulated with data and swept in a repetitive time pattern over a wide frequency range. The modulation of the carrier is so controlled that a characteristic of the data signal modulation has a predetermined relationship with respect to the repetitive sweep time pattern. The system receiver comprises a narrow-band IF channel coupled to the output of a mixer arranged to receive the incoming swept-carrier signal and a correspondingly-swept local oscillator signal. The sweep control signal for the local oscillator is developed by a circuit coupled to the mixer output and responsive to the data modulation on the IF signal. In one disclosed embodiment, the transmitter carrier is frequency-swept with a sinusoidal time pattern, the data signals have a biphase format with a frequency one-half that of the carrier sweep frequency, and the sweep control signal for the local oscillator is developed by directing the biphase data signals to a 2X frequency multiplier the output of which is filtered to produce a sinewave control signal for the local oscillator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.