Mesleh et al. showed that the spatial form of this process outperforms the standard approach for this process in MIMO (“my-moh”) setups like V-BLAST. A Mach-Zehnder interferometer with p-n junctions as arms can be used for this process in integrated photonics. This process can be undone by a circuit consisting of a diode in series with a parallel RC. The accuracy of this process can be confirmed using a constellation diagram, (-5[1])which displays four equidistant dots for (*) quadrature phase-shift keying. Circuits used to undo this task include the envelope detector and the superheterodyne receiver. The simplest form of this process consists of multiplying a carrier signal by a lower-frequency message signal. For 10 points, name this process of superimposing two signals, whose “amplitude” and “frequency” (10[1])types are used in radio transmission. ■END■