| According to the contract for Military Electronics Elements and Devices research project, this subject developed a new kind of small-scale high frequency band-stop quartz crystal filters for the urgent need of the equipment for some type Radar Systems of some establishment. We analyzed two kinds of designs about the crystal band-stop filters, and brought forward the flexible design of relative bandwidth of Cascade circuit band-stop crystal filters which was far-ranging applied. This article takes the 220MHz small-scale high frequency band-stop crystal filters as example designed and calculated. We solved the fabrication and application of the small-scale high frequency band-stop crystal filters in the practical engineering.The 220MHz small-scale high frequency band-stop quartz crystal filters was designed in the basis of band-pass-type band-stop crystal filters theory and the band-stop quartz crystal filters was carried out in the form of Cascade circuit.The technical features of this project are: high frequency (220MHz), long-term working temperature range(-55-+85), the Special request of the restraint of Center frequency (-15dB～+20dB) , Strong anti-vibration (Function tests: Power spectral density up to 0.14g2/Hz; Durability testing: Power spectral density up to 0.19g2/Hz, Vibration time: 2.5 hours)Some technical problems are: how to design high-frequency filter crystal and how to aggrandize the bottom-width of the stop-band of the high frequency band-stop crystal filters to ensure the stability of all the performance of the filter in long-term working temperature range and the good properties of the filter in strong vibration.The research of the high frequency band-stop quartz crystal filters has significant meaning in technologic progress and economic value. Because the development and application of the 220MHz small-scale high frequency band-stop quartz crystal filters meet the specifical need of the given complete set . And the device and manufacture of the high frequency filtering crystals, the practice experience and analysis in theory and design of the circuit of the high frequency quartz crystal filters as well as the printed wire layout have lay a stability foundation for other high-frequency band-pass and high frequency band-stop quartz crystal filters.Prior to this, the requirement for 220MHz high-frequency quartz crystal band-stop filter of The some establishment. completely rely on abroad imports. The information about 220MHz high-frequency quartz crystal band-stop filter belongs to high-end secrets. Especially after the embargo of high-end components for our country, we have received extremely limited information about the high-frequency quartz crystal band-stop filter. Through the comparative analysis of the scanty literature, the subject of the development of small-scale of high-frequency 220MHz band-stop quartz crystal filter has fully meet all the technical indicators of the parameters of foreign products. The stability performance in wide temperature range of our product and some other technical indicators has exceeded the United States products. The project of high-frequency of 220MHz small band-stop quartz crystal filter was identify in 2003 by the Group of Experts when we finalized the design: this technology is in the leading position in products of the same category in China. |
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