A multiplexing technique applicable to mosaic arrays of (2N-1)xM infrared photoconductors is described. This method employs bias coding. It represents an alternative funda-mentally different from the sequential-readout time-division multiplexing approach in general use. Some of the relevant theory of coding is summarized in both analytic and matrix form. Rationale is presented for the selection of binary codes in general, and maximal-length (pseudo-random) shift-register sequences in particular. Results obtained from a prototype, 31 x 31-element doped-silicon mosaic and data processing computer, oper-ating under low-background conditions, are described.