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Circuit and method for filtering a radio frequency signal

A radio frequency signal and circuit technology, applied in electrical components, frequency selective two-terminal pair network, impedance network, etc., can solve the problem of filter occupying circuit board area and packaging volume, etc.

Inactive Publication Date: 2007-02-28
INFINEON TECH AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above filters take up a lot of board area and package volume in the transceiver

Method used

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  • Circuit and method for filtering a radio frequency signal
  • Circuit and method for filtering a radio frequency signal
  • Circuit and method for filtering a radio frequency signal

Examples

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Embodiment Construction

[0018] A filter circuit 1 for filtering radio frequency signals according to an embodiment of the present invention is shown in FIG. 1 . The filter circuit 1 comprises an input 3, a filter device 5, and an active AC shunt 7 having a first input 7a and a second 7b and an output 7c, wherein the first input 7a is connected to the The input terminal 3 of the filter circuit 1 , the output terminal 7 c coincides with the output terminal of the filter circuit 1 .

[0019] The filter arrangement 5 comprises two resonant circuits 9 and 11 , one of which is a notch filter 9 and the other a bandpass filter 11 . The notch filter 9 is connected between the input 3 and the second input 7b of the active AC shunt 7 and comprises a capacitor 13 and an inductor 15 connected in parallel. The bandpass filter 11 is connected between the second input 7b of the active AC shunt 7 and ground G and comprises a capacitor 17 and an inductor 19 connected in series.

[0020] The active AC shunt 7 compris...

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PUM

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Abstract

A circuit (1) for filtering a radio frequency signal at a given frequency comprises an input terminal (3), a filter device (5), and an active AC shunt circuit (7) having first (7a) and second (7b) input terminals and an output terminal (7c), where the first input terminal (7a) of the active AC shunt circuit (7) is connected to the input terminal (3). The filter device (5) is connected between the input terminal (3) and the second input terminal (7b) of the active AC shunt circuit (7), and is provided for attenuating the radio frequency signal at the given frequency to the second input terminal (7b) of the active AC shunt circuit (7). The active AC shunt circuit (7) is provided for shunting a signal at a frequency other than the given frequency as contained in the radio frequency signal to ground (G), and for outputting the radio frequency signal as filtered at its output terminal (7c).

Description

technical field [0001] The present invention generally relates to radio frequency (RF) signal filters. Background technique [0002] A variety of active and passive RF and microwave filters are used in telecommunication devices to reject out-of-band signals, filter out unwanted harmonics and spurious components from signals before they are transmitted, and are used to implement various other functions. [0003] Specifically, a GSM filter may be required in the transmitter output of a Packet Switched Mobile (GSM) transceiver and a DCS filter may be required in the transmitter output of a Digital Cellular System (DCS) transceiver. Both types of filters are typically required in dual-mode telecommunications transceivers. Similar filters are also required in wireless local area network (WLAN) and wireless personal area network (WPAN) devices such as Bluetooth and 802.11 devices, for example to attenuate the second harmonic of a signal source. The aforementioned filters occupy...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03H11/04H04B1/40
CPCH03H1/0007H03H7/01H03H11/04H03H7/1791H03H7/1775
Inventor M·耶尔姆
Owner INFINEON TECH AG