A case-study on preventing desensitization of Radio Frequency Receivers
Shivashish Chakraborty, Siladitya Sen · 2014
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 interfering 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. A solution for this 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 non-interfering oscillator frequency for the microcontroller. Keywords-Desensitization, spurious IF, odd order inter-modulation, oscillator frequency.