Preventing Desensitization of Radio Frequency Receivers-a Realistic Approach

Desensitisation of radio receivers is important where a number of radio signals are present in close proximity to each other in an area. This may happen in Wi-Fi to cellular communications to Bluetooth as well as in many more traditional applications. When a signal is being received in the presence of a strong interfering signal, then non-linearities within the receiver mixer and amplifier results in generation of spurious IF. If the interferering signal is sufficiently strong, the resulting product will suppress all other signals reducing the effective gain of the device. This is caused by the odd order intermodulation products within a receiver amplifier or mixer chain. These affect the signal in such a way that the desired signal strength is reduced. In this paper we have proposed a solution to overcome this, which can be implemented if the check for spurious IF is made with the help of software and the result is utilized to switch on the noninterfering oscillator frequency for the microcontroller.

Author(s): Shivashish Chakraborty, Siladitya Sen

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