Look-Up Table for Superconductor Digital-RF Predistorter

We have developed a high-speed pipelined superconductor look-up table to generate programmable predistortion functions for direct linearization of radio frequency (RF) power amplifiers. The look-up table comprises an address decoder and a memory matrix with throughput above 10 GHz. The decoder performs code-matching of each input word and its conversion into a row address of the memory matrix. We discuss different possible implementations of the address decoder, including a preferred one for integrated circuit implementation. The memory matrix consists of RS flip-flops with nondestructive readout connected in series for slow-speed contents writing. Each row of the memory matrix contains a number, which can be read out by signal from the decoder. We present the design and the results of experimental evaluation of the look-up table and its components.