Even harmonic direct-conversion receiver, and a transmitting and receiving apparatus using the same
US6600911B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 30, 2000 |
| Grant date | Jul 29, 2003 |
| Priority date | — |
| Expiry date | May 30, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/403
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
If a local oscillation wave of a frequency approximately half the received signal frequency is input to a low noise amplifier 2, a dc offset voltage caused by the nonlinearity of the amplifier is produced, thus degrading reception sensitivity. This problem is resolved by disposing before the low noise amplifier 2 a filter means, such as a bandpass filter 12, band-elimination filter 13, or high pass filter 14, with characteristics for passing the received wave and suppressing a frequency band at approximately half the received wave frequency, thus preventing a radiation wave at substantially the same frequency as the local oscillation wave from being input to the low noise amplifier 2. A filter circuit 15 is also provided in the low noise amplifier 2 as a means for eliminating a radiation wave input to the low noise amplifier 2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.