Geometric harmonic modulation (GHM)-digital implementation
US5519692A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 20, 1995 |
| Grant date | May 21, 1996 |
| Priority date | — |
| Expiry date | Mar 20, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2601
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A set of phases defining an `address` and a `spreading key` is selected. These are employed in determining a preamble waveform and a traffic waveform. The preamble carrier waveform is a sum of a set of tones each offset by its phase, whereas the traffic carrier waveform is the product of these same offset tones. The tones have frequencies which are geometrically increasing multiples of a fundamental frequency. The phases and magnitudes of the preamble and traffic carrier waveforms are determined and prestored in a transmit and receive unit storage device. An inverse discrete Fourier Transform unit (IDFT) in the transmit unit receives the phase preamble offsets and magnitudes from the storage unit and creates a preamble carrier signal transmitted to the receive unit which determines if the phases match those which it is to listen to. If not, the following message is ignored; if they are, the following message is despread and decoded. IDFT creates a traffic carrier waveform from the traffic phases and magnitudes. Binary information is encoded in the carrier, processed and transmitted to the receive unit. A discrete Fourier Transform unit converts the received signal into phases and m…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.