QPSK modulator or demodulator using subharmonic pump carrier signals
US4612518A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 28, 1985 |
| Grant date | Sep 16, 1986 |
| Priority date | — |
| Expiry date | May 28, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/233
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a QPSK modulator or demodulator for modulating two different input bit streams with a subharmonic pump carrier signal to produce an appropriately encoded QPSK output signal. The subharmonic pump carrier signal used is a submultiple of a predetermined microwave or millimeter-wave carrier frequency. The QPSK modulator or demodulator is capable of being fabricated on a planar substrate using appropriate stripline filters and a mixer diode in each of an in-phase and quadrature signal path. A fin line arrangement, also capable of fabrication on the substrate, can be used to introduce an appropriately phased subharmonic pump carrier signal into each of the in-phase and quadrature signal paths before each mixer diode. Each mixer diode mixes the associated data bit stream and one of the two appropriately phased pump carrier signals to produce separate output signals which modulate along separate orthogonal axes, which output signals are combined to produce the QPSK modulator output signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.