Direct-conversion transmitting circuit and integrated transmitting/receiving circuit
US7116950B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Feb 12, 2002 |
| Grant date | Oct 3, 2006 |
| Priority date | — |
| Expiry date | May 8, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D2200/0047
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A transmitter is provided which includes a transmitting circuit that does not require a high-performance low noise VCO restricting cost reduction thereof and that can reduce the number of parts without requiring an RF filter. A direct conversion that does not require a transmission VCO is applied to the transmitting circuit. In order to achieve noise reduction in a receiving band, low-pass filters are provided a IQ input sections of a modulator that converts IQ signals into RF signals. In comparison with a conventional transmitter using offset PLL, an external VCO required in addition to an RF integrated circuit, a power amplifier, and a front end circuit is reduced. Even in current transistor performance, by using a filter having rapid waveform characteristics such as a SAW more inexpensive than the VCO, or the like, it is possible to provide a GSM/GSM 1800/GSM1900 triple band transmitter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.