Multi-tap radio frequency interference canceller based on surface acoustic wave device

Abstract

The invention relates to a multi-tap radio frequency interference eliminator based on an acoustic surface wave device. In the multi-tap radio frequency interference eliminator, a plurality of delay lines having fixed delay are connected in series. Radio frequency reference signals are inputted into a front end of the delay line. Each tap can output a signal having different delays (phase). Signalamplitudes of the taps are adjusted and then the signals are combined into one path of signals. The signals are combined with receiving signals, The delay line device in each tap is made by the acoustic surface wave device and is simple in structure, small in volume, stable in temperature and good in uniformity. An electronic switch is designed in each tap and the electronic switch is either switched on or off under control of the digital signal in order to flexibly choose a tap having a smallest delay error with a channel main path to eliminate self-interference.

Description

Technical field[0001]The invention relates to a method of combining interference cancellation with a multi-stage filter, in particular to a multi-tap radio frequency interference canceller based on a surface acoustic wave device, belonging to the field of wireless communication.Background technique[0002]Radio frequency interference cancellers usually adopt a single-tap structure, and the single-tap RF interference cancellation capability can reach 20dB. However, this structure has the following problems. First, the received interference delay is different from the reference signal delay, which will reduce the ability of interference cancellation, especially for wideband signals. In addition, when there is a reflector in the propagation environment around the antenna, there are multipath components in the received interference signal. Even if the reference signal and the direct signal with the strongest energy can be adjusted to cancel each other, the signals of other paths cannot be...

AI Technical Summary

Problems solved by technology

[0003] In the current research, coaxial cables are often used as delay lines, but it takes about 0.005μs for electromagnetic waves to propagate 1m in it, so the length of coaxial cables to meet the design requirements of radio frequency interference elimination cannot be accepted by engineering implementation

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