PC450 Instrumentation 0.5 Differential amplifiers, common mode signals and CMRR, isolation amps, preamps, electrometers, boxcar integrators, lock-in amplifiers, FFT and other signal processors, digital audio, instrument-to-instrument communication, tri-state bus drivers, RS 232, IEEE 488, and centronics parallel ports. Prerequisite: PC120, PC221 (or permission of the Department).