Ultrahigh frequency high image rejection filter

A technology of image suppression and ultra-high frequency band, which is applied in the direction of image communication, TV, color TV components, etc., can solve the problems of image frequency falling within the frequency band, signal distortion, etc., to suppress image frequency and harmonic interference, improve Effective signal gain and insertion loss reduction

Inactive Publication Date: 2012-06-13
CHONGQING UNIV
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  • Abstract
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Problems solved by technology

[0004] The object of the present invention proposes a high image rejection filter in the ultra-high frequency band, for the commonly used primary frequency conversion structure, the image frequency falls within the frequency band and the insertion loss brings signal distortion problem

Method used

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Embodiment Construction

[0024] The present invention will be further described below in conjunction with the accompanying drawings. Take the 470MHz-566MHz frequency band as an example:

[0025] Such as image 3 , 12 , Shown in 13: a kind of ultra-high frequency band high image rejection filter, comprise the amplifier 1 of amplifying received signal, notch wave filter 2, select and change the double tuned tracking filter 3 of channel, change the TV signal from different channels A mixer 4 for forming a TV intermediate frequency signal with a fixed frequency, and a surface acoustic filter 5 for filtering out various interferences and suppressing local oscillator radiation.

[0026] Such as Figure 13 Shown: the amplifier 1, the notch filter 2, the double tuned tracking filter 3, the mixer 4 of the TV intermediate frequency signal, and the surface acoustic filter 5 are connected in sequence to form the present invention.

[0027] Wherein, the double-tuned tracking filter 3 is provided with a sixth c...

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Abstract

The invention discloses an ultrahigh frequency high image rejection filter, which comprises an amplifier, a double-tuning tracking filter, a mixer and a surface acoustic filter and is characterized in that the double-tuning tracking filter is provided with a sixth capacitor, one end of the sixth capacitor is connected with a pre-stage circuit, and the other end of the sixth capacitor is connected with a front end of a first capacitor. A rear end of the first capacitor is connected with an outer end of a first inductor, an inner end of the first inductor is connected with inner ends of a second inductor and a third inductor, and inner ends of three inductors are connected with a positive pole of an alternating direct current power supply. An outer end of the third inductor is connected with the capacitor in series to be connected with the ground, and an outer end of the second inductor is connected with a second capacitor in series to be connected with a post-stage circuit. The ultrahigh frequency high image rejection filter has the advantages of not only effectively rejecting image frequency and harmonic interference in an ultrahigh frequency range, but also reducing insertion loss to some extent, and increasing useful signal gain.

Description

technical field [0001] The invention belongs to the technical field of digital television signal transmission, in particular to an ultra-high frequency band high image rejection filter. Background technique [0002] Terrestrial digital TV refers to "a TV system that uses terrestrial broadcasting to transmit digital TV signals. Its TV signals are broadcast to the air through TV towers, and then received by users in the form of antennas, and resolved through terrestrial digital TV tuners. The traditional TV reception method that is tuned. TV broadcasting is divided into four bands, namely I, III, IV, and V bands. The frequency range of I band is 48.5MHz-92MHz, and can receive channels 1-5. The frequency range of III band is 165MHz- 223MHz, can receive channels 6-12. The frequency range of IV band is 470MHz-566MHz, and can receive channels 13-24. The frequency range of V band is 606MHz-958MHz, and can receive channels 25-58. In a relatively simple, typical tuner once In the fr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04N5/44H04N5/50
Inventor 曾孝平熊东黎小娇赵宇刘国金王靖陈千杨学敏王峰
Owner CHONGQING UNIV
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