Modulation device and demodulation device
US8155235B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 30, 2008 |
| Grant date | Apr 10, 2012 |
| Priority date | — |
| Expiry date | Feb 13, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2027/0016
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Provided is a modulation device which generates a phase modulation signal and an amplitude modulation signal and can correct an I/Q orthogonal shift and reduce degradation of the ON/OFF ratio. In the device, a phase shifter (174) controls voltage applied to a capacitor in accordance with a control signal outputted from a phase control unit (180) and adjusts the capacitance so as to shift the phase of a carrier generated by an oscillator (173). The phase control unit (180) estimates a phase shift of a phase shifter (174) in accordance with an output RF signal (S140) by using the phase shift estimation method. Furthermore, the phase control unit (180) performs tuning of the phase shifter (174) according to the estimated value of the phase shift of the phase shifter (174) so that a phase difference between carries of an I signal (S125) and a Q signal (S135) is 90 degrees.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.