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Small group delay crystal filter

A crystal filter and group delay technology, applied in electrical components, impedance networks, etc., can solve the problems of large group delay fluctuations, steep attenuation characteristics, large delay indicators, etc., and achieve flat group delay characteristics and excellent performance , Convenience and production effect

Inactive Publication Date: 2012-10-31
XIANYANG ZHENFENG ELECTRONICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] The group delay of ordinary crystal filters is about 10us ~ 40uS, and some group delay indicators are even larger
The group delay index of the small group delay crystal filter is required to be less than 1.8uS, and the ordinary crystal filter uses a Chebyshev type function, which has the defects of steep attenuation characteristics, equal ripples, and large group delay fluctuations.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] 24.384MHZ (1.8uS) crystal filter (fundamental frequency) adopts Bessel function characteristics, uses 6 crystals and 6 frequency points, ordinary filter 6 crystals and 4 frequency points; 6 frequency points are all made of aluminum technology; magnetic Material selection of new magnetic materials (μ 0 =9) See the attached picture for the circuit diagram:

[0053] The frequency points of F1-F6 quartz crystal resonators are as follows:

[0054] F1: UM-1 -58—-58.3KHz

[0055] F2: UM-1 +20—+20.3KHz

[0056] F3: UM-1 -31—-31.3KHz

[0057] F4: UM-1 +11.2—+11.5KHz

[0058] F5: UM-1 -41.9—-42.2KHz

[0059] F6: UM-1 +39—+39.3KHz

[0060] L1 and L2 are chip inductance values ​​as follows:

[0061] L1: 2520-3.3uH

[0062] L2: 2520-3.3uH

[0063] C1-C3 are chip capacitor values ​​as follows:

[0064] C1: 0802-12PF

[0065] C2: 0805-1PF

[0066] C3: 0805-12PF

[0067] B1-B3 are issued as follows for the new ferrite magnetic surround:

[0068] B1, B3 double wire and win...

Embodiment 2

[0073] 70MHZ (1.8uS) crystal filter (fundamental frequency) also adopts the above scheme and method. The circuit diagram and data are as follows:

[0074] The frequency points of F1-F6 quartz crystal resonators are as follows:

[0075] F1: UM-1 -70—-70.3KHz

[0076] F2: UM-1 +13.6—+13.9KHz

[0077] F3: UM-1 -36—-36.3KHz

[0078] F4: UM-1 +9.8—+9.1KHz

[0079] F5: UM-1 -40.9—-41.2KHz

[0080] F6: UM-1 +27—+27.3KHz

[0081] L1 and L2 are chip inductance values ​​as follows:

[0082] L1: 2520-10nH

[0083] L2: 2520-10nH

[0084] C1 and C3 are chip capacitor values ​​as follows:

[0085] C1: 0805-9.1PF

[0086] C3: 0805-9.0PF

[0087] B1-B3 are issued as follows for the new ferrite magnetic surround:

[0088] B1 and B3 are double-wired and wound 8 times

[0089] B2: Double wire and wind 10 times

[0090] CWC1-CWC3 are fine-tuning capacitors, all of which are CWC35 type 2.8-10PF

[0091] The group delay index of the developed crystal filter is less than 1.8uS, and the...

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PUM

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Abstract

The invention discloses a small group delay crystal filter. An input circuit is connected with a resonance bridge and then connected with a crystal resonance element 12, passes through a widening circuit, then is sequentially connected with a crystal resonance element 34 and a resonance bridge, passes through a widening circuit, then is connected with a crystal resonance element 56, and finally is connected with an output circuit. By aid of the circuit connection mode, the small group delay crystal filter has the advantages of being good in performance, simple in structure, convenient to use, capable of being used in a temperature range of -55 DEG C to +85 DEG C, good in stability, small in pass band fluctuation, good in stop band attenuation and capable of improving digital sensitivity, and can be widely applied to mobile communication system products. In addition, the group delay index is smaller than 1.8 uS (centre frequency is + / -20k).

Description

technical field [0001] The invention relates to a mobile communication system product, in particular to a small group delay crystal filter. Background technique [0002] The group delay of ordinary crystal filters is about 10us to 40uS, and some group delay indicators are even larger. The group delay index of the small group delay crystal filter is required to be less than 1.8uS. The common crystal filter uses a Chebyshev type function, which has the disadvantages of steep attenuation characteristics, equal ripples, and large group delay fluctuations. Contents of the invention [0003] The purpose of the present invention is to provide a crystal resonator element with excellent performance, easy to produce, used in the temperature range of -55°C-+85°C, good stability, flat group delay characteristics, small fluctuations in the passband, high digital sensitivity A small group delay crystal filter with a frequency of 24.384MHZ. [0004] Another object of the present invent...

Claims

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Application Information

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IPC IPC(8): H03H9/58
Inventor 刘建国李宁李茹
Owner XIANYANG ZHENFENG ELECTRONICS
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