Wave filter circuit

Abstract

The invention provides a filter circuit, which is applied to the VDSL communication field. The invention consists of a plurality of inductor units, a plurality of resonant capacitors, a plurality of impedance matching circuits, and a plurality of attenuation capacitors. The inductor units are communicated in series between the input end and the output end of the filter circuit, each resonant capacitor is communicated in parallel between every two inductor units. Each of the impedance matching circuits is communicated to one of the inductor units respectively, and each of the attenuation capacitors is communicated to one of the impedance matching circuits and to one of the inductor units respectively.

Description

technical field [0001] The present invention relates to a filter circuit used in the field of communication, in particular to a filter circuit applicable to the field of VDSL (Very high bit-rate DSL) communication. Background technique [0002] Please refer to FIG. 1 , which is a schematic diagram of the circuit composition of a known filter circuit 1 used in the field of VDSL communication. The filter circuit 1 has an input terminal input and an output terminal output, and between the input terminal input and the output terminal output There are a plurality of inductor groups L1-L6, a plurality of capacitors C1-C9 and a plurality of resistors R1-R4. [0003] The input terminal input of the filter circuit 1 includes a two-pin contact, a loop (tip, ring), which is electrically connected to a communication line of a communication device (not shown in the figure), and the output terminal output also includes two pins Contacts, loops (tip, ring), which can be electrically conne...

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Problems solved by technology

[0008] Please refer to Fig. 2, which is a frequency response diagram of the filter circuit 1 of Fig. 1, as shown in the figure, it has a first frequency response line lineH, a second frequency response line lineL, and the above-mentioned filter circuit 1 An actual frequency response line lineR generated, the first frequency response line lineH and the second frequency response line lineL are all formulated by the European Telecommunications Standards Institute (ETSI) in TS 101 952-2-1 in the VDSL2 transmission agreement The threshold value of the standard, which stipulates that when the frequency response is above 30MHZ, the noise should be below -55dB before passing the standard, but as shown in the figure, when the frequency response of the known filter circuit 1 is 30MHZ, the noise is only -42.093dB , obviously cannot be applied to the specifications formulated by the European Telecommunications Standards Agency

Furthermore, the known filter circuit 1 uses at least six inductance groups L1-L6, nine capacitors C1-C9 and four resistors R1-R4. In the industry of miniaturization and cost reduction of communication products, the performance of this known filter circuit 1 is really insufficient, so there is a need for improvement

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