Automatic frequency calibration channel selection filter for multi-frequency multi-mode wireless transceiver

A technology of automatic frequency calibration and wireless transceivers, applied in transmission systems, electrical components, etc., can solve problems such as poor high-frequency characteristics and low absolute accuracy

Inactive Publication Date: 2011-04-06
EAST CHINA NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

When the input signal swing is too large, the MOSFET-C filter will have a large nonlinearity. Using a differential structure can improve the linearity of the circuit, but due to the influence of the parasitic capacitance of the MOS tube, its high-frequency characteristics are not as good as the ACTIVE-RC filter. The Gm-C filter has good high-frequency characteristic

Method used

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  • Automatic frequency calibration channel selection filter for multi-frequency multi-mode wireless transceiver
  • Automatic frequency calibration channel selection filter for multi-frequency multi-mode wireless transceiver
  • Automatic frequency calibration channel selection filter for multi-frequency multi-mode wireless transceiver

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Embodiment Construction

[0022] In the channel selection filter of the present invention, the adjustment of the cutoff frequency is realized in this way. The three digital signal input terminals A1, A2 and A3 of the decoder C have a total of eight combinations of input signals, which are respectively 000, 001, 010 . The switch control bits CON1, CON2, CON3, CON4, CON5, CON6, CON7 and CON8 of the switch resistor array B1, B2 and B3, if the switch control bit is high level, the resistor connected in series with it is turned on, otherwise the resistor is turned off , the equivalent impedance of the switched resistor array can be adjusted, the switched capacitor array is based on the same principle, and the cutoff frequency of the filter is equal to Where RB2 is the equivalent impedance of the second switch resistor array B2, RB3 is the equivalent impedance of the third switch resistor array B3, CF is the value of the capacitor F, and CE is the equivalent capacitance value of the switch capacitor array E...

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Abstract

The invention discloses an automatic frequency calibration channel selection filter for a multi-frequency multi-mode wireless transceiver, which comprises a fully differential operational amplifier, three switch resistance arrays, a decoder, an automatic frequency calibration circuit, two switch capacitance arrays and a capacitor. The filter can be applied to multi-frequency multi-mode wireless transceivers which support wireless local area network, global mobile communication, radio frequency identification and time division synchronous code division multiple accesses. The filter supports eight different frequency bands, reduces the implementation cost of the system and improves the integrity of the system. The automatic frequency calibration circuit of the filter can realize the accurate adjustment of a cut-off frequency, and the error is within 3 percent.

Description

technical field [0001] The present invention relates to a channel selection filter, in particular to a filter that simultaneously supports Radio Frequency Identification (UHF RFID), Time Division Synchronous Code Division Multiple Access (TD-SCDMA), Global System for Mobile Communications (GSM), Wireless Local Area Network (WLAN 802.11 a / b / g) Multi-frequency multi-mode channel selection filter. Background technique [0002] With the rapid development of wireless communication technology, new technologies and standards emerge in an endless stream. Users hope that they can freely access the corresponding network for communication according to their own needs through multi-mode terminals in their hands, so as to realize flexible, convenient and unlimited free communication. , the future development trend will be the continuous integration of various wireless technologies. [0003] The multi-mode multi-band wireless transceiver can simultaneously meet the three application req...

Claims

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Application Information

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IPC IPC(8): H04B1/40
Inventor 谢淼任旭马聪黄飞朱彤张润曦赖宗声
Owner EAST CHINA NORMAL UNIVERSITY
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