Radio receiver with switching circuit for elimination of intermodulation interference
US4654884A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 1985 |
| Grant date | Mar 31, 1987 |
| Priority date | — |
| Expiry date | May 10, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/109
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A radio receiver includes a first tuner, a first intermediate-frequency amplifier, at least two intermediate-frequency filters connected between the first tuner and the first intermediate-frequency amplifier and having difference frequency bands, a switching circuit for applying an output signal from the first tuner through a selected one of the intermediate-frequency filters to the first intermediate-frequency amplifier, an automatic gain control circuit for controlling the gain of the first tuner, a first phase-locked loop for enabling a local oscillator in the first tuner to oscillate at a frequency dependent on the frequency of a desired channel, a second tuner, a level detector circuit for detecting the level of an output signal from the second tuner, a second phase-locked loop for enabling a local oscillator in the second tuner to oscillate at a prescribed frequency, and a controller for controlling the first phase-locked loop to enable the first tuner to receive and issue a desired signal from a desired channel, for controlling the second phase-locked loop to enable the second tuner to receive and issue signals from the desired channel and other channels, for enabling the le…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.