.pi./4 shift QPSK modulator and communication apparatus
US5210775A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 12, 1991 |
| Grant date | May 11, 1993 |
| Priority date | — |
| Expiry date | Feb 12, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2092
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A .pi./4 shift QPSK modulator for receiving digital signals and for outputting a modulated signal therefrom in accordance with each of the inputted digital signals. The .pi./4 QPSK modulator is utilized in a communication apparatus and includes a counter for counting the number of the inputted digital signals, a phase information arithmetic unit for receiving a value of an output from the counter and a value of each of the inputted digital signals for outputting phase information of the signal to be modulated, an arithmetic unit for performing an arithmetic operation on values representing an impulse response of the output phase information from the phase information arithmetic unit and outputting impulse response values in accordance therewith, and an accumulating unit for accumulating impulse response values outputted from the arithmetic unit and for performing an arithmetic operation for enabling generation of a .pi./4 shift QPSK modulated signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.