Radio frequency signal preselector for electric tuning

A technology of radio frequency signals and preselectors, applied in electrical components, transmission monitoring, transmission systems, etc., can solve problems such as inconvenient use, high cost, and large volume of switch filter matrix, and achieve flexible and convenient use, good effect, and compact size The effect of cost reduction

CN102723960AActive Publication Date: 2012-10-10CHINA ELECTRONIS TECH INSTR CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2012-10-10

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Abstract

The invention discloses a radio frequency signal preselector. The frequency range of the radio frequency signal preselector is DC-4 GHz, the requirement of low waveband of an electromagnetic interference test receiver on the signal preselector is satisfied, and full-waveband signal preselection of the electromagnetic interference test receiver can be realized in combination with a high-waveband YIG (Yttrium Iron Garnet) signal preselector. The signal preselection technology of covering the low waveband of the electromagnetic interference test receiver is realized by a scheme of combining tunable filters, and the filter quantity is greatly reduced in comparison with that of a switch filter matrix comprising fixed filters, so that both the volume and the cost are greatly reduced. The filters are integrally embedded in the electromagnetic interference test receiver and are flexible and convenient to use. The tunable filters realize the signal preselection, the scanning central frequency of the electromagnetic interference test receiver and the central frequency of the preselector can be guaranteed to be the same, the filter bandwidths in the wavebands can be adjusted, and the signal preselection effect is better.
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Description

technical field

[0001] The invention relates to a radio frequency signal preselector, in particular to an electrically tuned radio frequency signal preselector. Background technique

[0002] In modern superheterodyne receivers, due to the nonlinear characteristics of frequency converters, harmonics, image frequencies and other spurious signals of radio frequency signals will confuse the measurement results. Measures must be taken to suppress these spurious signals when designing the receiver. To limit its influence on the measurement results, the main method is to design a signal preselector.

[0003] In order to meet the selectivity and impulse response index requirements in the electromagnetic compatibility test standard (hereinafter referred to as: standard), the electromagnetic interference test receiver (hereinafter referred to as: receiver) generally needs to add a signal pre-selection device at the front end of the receiver. Since the receiver is generally divided in...

Examples

Embodiment Construction

[0015]The reason why the existing switch filter matrix preselector is large in size and high in cost is that it uses a filter with a fixed center frequency and bandwidth. In order to perform signal preselection, it can only switch between filters with different center frequencies and bandwidths. Considering that the high-band YIG filter uses a band-pass filter with tunable center frequency, the signal preselection is realized by tuning the center frequency; only one filter is small in size and easy to use. If the low band uses an adjustable filter instead of a fixed filter for signal preselection, the volume should also be reduced. Since no single type of tunable filter can cover the entire low-band receiver, to use tunable filters for low-band signal preselection, multiple different tunable filters are used in parallel with the switching filter matrix. Similar to using a switch control to switch between different filters. Since one tunable filter can replace the signal prese...