公开(公告)号：US07835434B2

公开(公告)日：2010-11-16

申请号：US10481845

申请日：2002-05-21

Applicant: Thien Luong Huynh ,  Anil Gercekci ,  Anthony David Newton

Inventor： Thien Luong Huynh ,  Anil Gercekci ,  Anthony David Newton

IPC: H03H7/40

CPC classification number: H03J3/08 ,  H03H21/0001 ,  H04B1/0458 ,  H04B1/18 ,  H04L27/2601

Abstract: The invention relates to an adaptive Radio Frequency (RF) filter (11), which is particularly useful as an RF filter in Wireless Local Area Networks (WLAN's). As greater demands are placed on RF systems, for example in WLAN's in order to increase channel capacity by utilizing available bandwidth, corresponding demands are placed upon performance and tolerance of components used in FR circuits. An adaptive Radio Frequency (RF) filter for filtering first and second RF signals from an OFDM encoded carrier signal is provided, the adaptive RF filter comprises: a low-pass filter (102) configured to filter first and second RF signals, one from another, so as to provide a first RF output signal; the adaptive RF filter being tunable in response to one or more input signals, the at least one input signal being derived from a comparator (37,100), which compares the first RF output signal with a desired value for said first RF output signal, and provides a connection factor for varying a characteristic of the filter (102). An advantage of the invention is that it facilitates filter of two OFDM encoded RF signals, the first typically at 8.1 MHz and the second (unwanted) at 11.9 MHz, from a base-band signal, with a noise floor level of —55 dB or better. Another advantage is that the filter is able to self calibrate and is able to take into account fluctuations which may affect performance, for example thermal drift, and automatically trim its characteristics so as to compensate for these fluctuations.

Abstract translation: 本发明涉及一种自适应射频（RF）滤波器（11），其特别适用于无线局域网（WLAN）中的RF滤波器。 随着对RF系统的更大要求，例如在WLAN中，为了通过利用可用带宽来增加信道容量，对FR电路中使用的组件的性能和容限有相应的要求。 提供了一种用于从OFDM编码的载波信号滤波第一和第二RF信号的自适应射频（RF）滤波器，所述自适应RF滤波器包括：低通滤波器（102），被配置为从另一个滤波器滤波第一和第二RF信号 ，以便提供第一RF输出信号; 所述自适应RF滤波器响应于一个或多个输入信号是可调谐的，所述至少一个输入信号从比较器（37,100）导出，比较器将第一RF输出信号与所述第一RF输出信号的期望值进行比较，并且提供 用于改变过滤器（102）的特性的连接因子。 本发明的一个优点在于它有助于滤除两个OFDM编码的RF信号，第一个通常在8.1MHz，而在11.9MHz的第二个（不需要的）来自基带信号，噪声底层电平为-55dB， 更好。 另一个优点是滤波器能够自校准，并且能够考虑可能影响性能的波动，例如热漂移，并且自动调整其特性以补偿这些波动。