1. A direct conversion radio-frequency receiver, comprising: a replicator having a first array of elements, the replicator generating a first signal having a frequency responsive to a time constant; a digitizer configured to receive the first signal from the replicator, the digitizer generating a control signal responsive to the first signal; and a word generator configured to receive the control signal and a reference signal, the word generator generating an output word responsive to process variation in the semiconductor material used to implement the replicator.