Duplexer and electronic apparatus using the same

A duplexer and circuit technology, applied in the direction of circuits, filters, electrical components, etc., can solve the problems of characteristic increase and characteristic decline

Inactive Publication Date: 2004-07-14
TAIYO YUDEN KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This publication does not deal with a duplexer in which a characteristic rise (or fall) of one filter affects a characteristic fall (or rise) of the other filter

Method used

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  • Duplexer and electronic apparatus using the same
  • Duplexer and electronic apparatus using the same
  • Duplexer and electronic apparatus using the same

Examples

Experimental program
Comparison scheme
Effect test

no. 1 example

[0065] Fig. 4 shows a duplexer according to a first embodiment of the present invention. In FIG. 4 , the same elements as the aforementioned elements are denoted by the same reference numerals as the aforementioned ones. The duplexer shown in FIG. 4 includes a ladder-type surface acoustic wave filter 32 and a longitudinally coupled dual-mode surface acoustic wave filter 33 . The ladder-type surface acoustic wave filter 32 is the transmitting filter of the duplexer, and the longitudinally coupled dual-mode surface acoustic wave filter 33 is the receiving filter. These filters 32 and 33 have different band center frequencies. One end of the ladder-type surface acoustic wave filter 32 is connected to the common terminal 14 , and the other end is connected to an individual terminal (transmitting terminal) 15 . Similarly, one end of the longitudinally coupled dual-mode surface acoustic wave filter 33 is connected to the common terminal 14 via the matching circuit 11 , and the oth...

no. 2 example

[0075] Fig. 6 shows a duplexer according to a second embodiment of the present invention. In this figure, the same elements as in the first embodiment are designated by the same reference numerals as in the first embodiment. The duplexer shown in FIG. 6 is different from that of the first embodiment in that the receive filter has a balanced (differential) output through a modified connection. The duplexer shown in FIG. 6 has such a receive filter 45 . The comb electrodes of the IDT 37 of the DMS filters 34 and 35 which are grounded in FIG. 4 are connected to each other and also to the receiving terminal 46 . A balanced output is obtained via the receive terminal 46 and the further receive terminal 16 .

[0076] Figure 7A and 7B A balanced output is shown. The duplexer shown in Figure 6 is Figure 7A The duplexer 100 in. A balanced output is a signal output with the same amplitude and opposite phase, such as Figure 7B As shown in received signal 1 and received signal ...

no. 3 example

[0078] Fig. 8 shows a duplexer according to a third embodiment of the present invention. In this figure, the same elements as in the previous embodiment are indicated by the same reference numerals as in the previous embodiment. The reception filter 50 of this embodiment has a structure in which one or more DMS filters connected in parallel are cascaded. In the example shown in Figure 8, one set of two DMS filters 34 and 35 is connected to another set of two DMS filters. In FIG. 8 , the two DMS filters of the second stage connected in parallel are indicated by reference numerals 51 and 52 . The comb electrodes of the IDT 37 of the DMS filters 34 and 51 are connected to each other, and the comb electrodes of the IDT 38 of the DMS filters 34 and 51 are connected to each other, as shown in FIG. 8 . For simplicity of drawing, reference numerals 37 and 38 are assigned only to the IDT of the DMS filter 34 . The comb electrodes of the IDTs 37 and 38 of the DMS filters 35 and 52 ar...

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PUM

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Abstract

A duplexer includes two surface acoustic wave filter having different band center frequencies, and a phase matching circuit that matches the phases of the two surface acoustic wave filters to each other. In this duplexer, one of the two surface acoustic wave filters is a ladder type surface acoustic wave filter, while the other one of the two surface acoustic wave filters includes two or more dual-mode type surface acoustic wave filters that are connected in parallel.

Description

technical field [0001] The present invention relates to a duplexer using a bandpass type surface acoustic wave filter. Background technique [0002] In recent years, as mobile communication systems have been developing, portable phones and portable information terminals have also been expanding rapidly. In this trend, manufacturers are also scrambling to develop terminals with higher performance and smaller size. Systems for cellular phones include both analog systems and digital systems, and frequency bands used in these systems include various ranges such as 800 MHz to 1 GHz band and 1.5 GHz to 2.0 GHz band. [0003] Through the recent development of portable phones, portable terminals are now operating in dual-mode (such as a combination of analog and digital modes, or a combination of two digital modes: TDMA (Time Division Multiple Access) and CDMA (Code Division Multiple Access)) and dual-band ( The combination of 800MHz band and 1.9GHz band, or the combination of 900...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03H9/00H03H9/05H03H9/10H03H9/25H03H9/64H03H9/72
CPCH03H9/725H03H2250/00H03H9/72H03H9/6436H03H9/0576H03H9/6469H03H9/6483H03H9/0085H03H9/0076H03H9/6476H03H9/0028H01L2224/48227H01L2224/73265H01L2924/15153H01L2924/15313H01L2924/16195H03H9/64
Inventor 岩本康秀井上将吾伊形理堤润
Owner TAIYO YUDEN KK
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