.pi./4 quadrature phase shift keying modulator
US5373532A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1992 |
| Grant date | Dec 13, 1994 |
| Priority date | — |
| Expiry date | Sep 11, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2082
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A .pi./4 shift QPSK modulator includes a pre-processing part for subjecting an input transmitting code sequece to a pre-processing, a modulator part for selectively subjecting the transmitting code sequence received via the pre-processing part to a modulation in conformance with QPSK and a modulation in conformance with a .pi./4 shift QPSK, and an output part for outputting a modulated signal having a burst form based on an output of the modulator part depending on a burst signal having leading and trailing edges, where the pre-processing part carries out the pre-processing so that I-axis and Q-axis data supplied to the modulator part have the same symbol in succession at parts corresponding to the leading and trailing edges of the burst signal, so as to suppress generation of unwanted waves in the output part.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.