Two effective schemes of linearization are introduced for radio-frequency receivers in this paper. The first of these comprises a mixed-signal feed forward path which regenerates third-order inter-modulation (IM3) products at radio frequencies; down converts these products, digitizes them, and then utilizes them in the digital baseband portion of a nominally receiver path which is linear for cancelling IM3 products. To enable this mixed-signal feed forward path, a multistage cubic term generator is introduced which utilizes cascaded nonlinear operations for generating reference IM3 products. Examine the multistage nature of this circuit in the context of the aforementioned linearization scheme and is exhibit for providing sufficient dynamic range for nearly complete cancellation of IM3 product while dissipating is far less power than front end of the original receiver. Particularly, the effect of the group delay between stages is analyzed and shown to permit large IM3 cancellation ratios for delays of inter-stage group. To compensate for inter-modulation distortion terms of order which are greater than 3, products of IM3 and IM2 are processed down for baseband which is digitalized where they are successively multiplied for generating approximations to terms which are in higher-order.
Volume 11 | Issue 1