A multiple access digital up converter/modulator includes selectors (1606, 1608) having inputs (1602, 1604) and outputs coupled to first and second interpolating filters (1610, 1626). The output of the first interpolating filter is selectively coupled to a first mixer (1612) and a first adder (1622),...http://www.google.co.uk/patents/US5854813?utm_source=gb-gplus-sharePatent US5854813 - Multiple access up converter/modulator and method
