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Signal tuning with variable intermediate frequency for image rejection and methods

A technology of image signal and image channel, which can be applied to improve frequency converters, continuous tuning components, resonant circuit drive/adjustment devices, etc., and can solve problems such as complex filter/mixer circuits

Active Publication Date: 2012-11-14
FRESCO MICROCHIP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] All of these techniques require relatively complex filter / mixer circuits, and they all have their own drawbacks

Method used

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  • Signal tuning with variable intermediate frequency for image rejection and methods
  • Signal tuning with variable intermediate frequency for image rejection and methods
  • Signal tuning with variable intermediate frequency for image rejection and methods

Examples

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Embodiment Construction

[0024] figure 1 Shows a spectrum including channels to be mixed to IF for demodulation using a superheterodyne receiver / tuner. As shown, the selected IF frequency to which the channel of interest is tuned or mixed is centered at F IF place. The instance channel of interest is shown centered at F CHANNEL place. The channel can be passed with the mixing frequency F MIX Mix to tune or mix to a selected frequency.

[0025] For high-side injection (F MIX >F CHANNEL ), F MIX , F CHANNEL and F IF related, where F MIX -F CHANNEL =F IF . Therefore, by adjusting F MIX , different selected channels can be tuned to be centered at F IF IF band at , for further processing, demodulation and / or decoding.

[0026] In addition to the F MIX -F IF The channel at is tuned out of the IF band, F MIX The mixed signal at will be centered at F MIX +F CHANNEL =F I The signal is tuned to center at F IF the intermediate frequency band. This is obviously acceptable if there is no si...

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Abstract

The invention relates to signal tuning with variable intermediate frequency for image rejection and methods. In a method and apparatus for operating a super-heterodyne receiver, a tuning circuit has a local oscillator for frequency shifting a desired channel to a selected frequency and a controller for controlling the local oscillator. The controller determines for each of a number of identified channels, whether an image signal is present at frequencies in the spectrum that when tuned to a first selected frequency interfere, and is operable to select a modified selected frequency at which interference between the image signal and the identified channel is reduced.

Description

[0001] Cross References to Related Applications [0002] This application claims a Provisional U.S. Patent Application Serial titled "SIGNALTUNING WITH VARIABLE INTERMEDIATE FREQUENCY FORIMAGE REJECTION AND METHODS" filed January 11, 2010 priority of no. 61 / 294,092, the contents of which are incorporated herein by reference. technical field [0003] This invention relates generally to signal tuning circuits, and more particularly to tuner / receivers with variable frequency tuning for image suppression. Background technique [0004] Tuning circuits, such as superheterodyne tuners, are commonly used in communication equipment, such as radios, televisions, and the like. A superheterodyne tuner usually includes one or more mixers for frequency shifting (or mixing) the channel to be received to an intermediate frequency. At an intermediate frequency, the channel can be decoded / demodulated into a baseband signal. [0005] The amount by which the signal is shifted by the local os...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03J1/06H03J3/02H04B1/26
CPCH04B1/28H03D7/18H04B1/1027H03J1/06H03J3/02H04B1/26
Inventor J·特里哈勃L·格丽格盖恩G·成S·A·贾特兹
Owner FRESCO MICROCHIP
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