Current switching apparatus including at least one current switching tree comprised of cascaded sets of switching circuits, with an input set operable with sampling clock pulses supplied at a fixed frequency and the remaining cascaded sets operable at different frequencies, and further including a sample...http://www.google.ca/patents/US5218363?utm_source=gb-gplus-sharePatent US5218363 - High-speed switching tree with input sampling pulses of constant frequency and means for varying the effective sampling rate
