The development of a new frequency tuning method for reducing noise enhancement is introduced. A mathematical derivation has been developed to predict the size and position of the unwanted images. The signal image can be
removed by pre-distorting the input signal. The above improvements will enhance the use of all-digital ΣΔ based transmitters in future wireless communication system.
The management of distortion and noise is a key design challenge as is the requirement for tunability. ΣΔ techniques can shape the noise away from the carrier
band for subsequent removal in a band-pass filter, but tunability remains a problem. The proposed scheme needs to have two distortion function units: pre-distortion for
image cancellation (it is put at the input to the ΣΔ) and post-distortion for noise cancellation.