Digital modulation circuit
US5157693A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 1, 1991 |
| Grant date | Oct 20, 1992 |
| Priority date | — |
| Expiry date | Apr 1, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2092
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A modulator circuit for generating a modulated, DQPSK signal. The modulator circuit includes an encoder for receiving a binary bit stream comprised of bit pairs defining differential phase changes. An encoder receives a bit stream of which bit pairs thereof define differential phase changes. The encoder encodes the bit pairs into codewords which are stored and then supplied to an I-accumulator, a Q-accumulator, and a memory element. The memory element contains pre-multiplied values which are supplied to the I- and the Q-accumulators which add terms of the pre-multiplied values to form I-portions and Q-portions of a DQPSK-modulated signal. The I- and Q-portions may then be supplied to a quadrature modulator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.