Abstract: An in-line air purifier (110) for removing contaminants from a compressed air line includes an enclosure (112) having a carrying handle (124), a side wall (116) hinged (118) to a base (114), clasps (120, 122) for releasably closing the side wall (116) onto the base (114), and air inlet (126) and outlet (154, 156) couplers carried on the base (114) for coupling the purifier (110) in a compressed air line. A two stage assembly including replaceable cartridges (40, 42, 90) for removing oil and water, a bed (60) of activated charcoal, and a catalytic bed (76) for carbon monoxide is provided within the base (114) and connected between the inlet (126) and outlet (154, 156) couplers for removing contaminants in compressed air passing therethrough. An air monitor (162) is also provided within the base (114) and connected (157, 158, 160) to the outlet coupler (154, 156) for continuously sampling air passing through the outlet coupler (154, 156).

Abstract: A narrow band complex input signal, typically having multiple independently modulated carriers, is processed to produce an output signal which, while containing the information in the input signal, is not an amplitude dependent signal, and thus can be transmitted through nonlinear media, such as a saturated power amplifier, as a less expensive and more power-efficient alternative over a conventionally required linear power amplifier. The process separates the multiple input signals into an amplitude-limited angle-modulated carrier component and an envelope component, and then combines these components by a form of pulse-duty-factor modulation such as pulse-duration modulation, at a sufficiently high sampling rate. The combined signal is input to a nonlinear power amplifier. Unwanted sidebands are rejected by bandpass filtering at the amplifier output so as to pass only the carrier and its signal bandwidth.