A circuit and method for improving RF interference of dual-mode terminal

Abstract

The invention discloses a circuit for improving dual-mode terminal radio interference and a method thereof. The circuit of the invention is applied to a GSM / CDMA dual-mode mobile terminal, and comprises a receiving wave filter, a low noise amplifier and a duplexer, and further comprises a radio frequency switch used for synchronously disconnecting a CDMA receiving path at the transmitting timeslots of the GSM. The radio frequency switch is arranged between the low noise amplifier and the duplexer or between the receiving wave filter and the low noise amplifier, and a control terminal of the radio frequency switch is connected with a control circuit of the GSM. By adopting the technical proposal of the invention, the interference strength of the GSM can be reduced and the receiving sensitivity of the CDMA can be improved when the transmitting frequency of the GSM is close to the receiving frequency of the CDMA and under the situation that the receiving sensitivity of the CDMA is greatly influenced.

Description

technical field [0001] The invention relates to the field of wireless communication, in particular to a circuit and a method for improving the GSM / CDMA dual-mode terminal GSM transmission affecting CDMA sensitivity. Background technique [0002] The GSM / CDMA dual-mode mobile phone is a mobile terminal that supports both GSM and CDMA systems and is on standby at the same time. This type of communication terminal needs to support wireless modules of two standards to work at the same time. However, when the operating frequencies of the two wireless modules are close to each other, there will be mutual interference, which will have a certain impact on their respective wireless performance. This phenomenon is referred to as GC (GSM / CDMA) mutual interference. [0003] There are many types of GC mutual interference, and the present invention focuses on the influence of the GSM transmitted signal on the quality of the CDMA received signal in the CDMA receiving circuit. [0004] In...

AI Technical Summary

Problems solved by technology

[0006] 2) At present, the performance requirements for CDMA receiving filters are determined under standard CDMA communication conditions. The requirements for far-end out-of-band suppression are relatively loose, and there are large differences between CDMA receiving filters from different manufacturers. For CDMA receiving frequency bands Inhibition ability is different

[0007] The combined result of the above two factors will cause the CDMA mixer input carrier-to-noise ratio to deteriorate differently at the moment when the GC dual-mode mobile phone transmits in GSM, which in turn will lead to different deterioration degrees of CDMA receiving sensitivity.

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