US. Patent 386 Dec. 7, 2010 Sheet 4 of8 389 M1 Synthesizer M2 496 , Processor 396 US 7,847,178 B2 S2 M1 7 497 M3 + MA3 DAC ——0 3 9 ' Synthesizer 47 Processor ‘ 9 MA3 DAC —0 FIG. 6