Conventional sigma-delta (\sum\vartriangle) analog-to-digital (Ad) converters are based on an active analog \sum\vartriangle modulator followed by a digital filter. In earlier papers we proposed a new architecture for a first-order \sum\vartriangle modulator that needs no active analog components. Its advantage is that Ad converters can be implemented within Fpga?s or directly in the software of microprocessors. Its disadvantage is, however, that it realizes a lossy \sum\vartriangle modulator with an accompanying limited resolution. Here we propose to use dither-injection to relax that resolution limitation and we present simulation results showing that our ideas work.