Abstract: Dopable, fully dense polymer membranes are used to form membranes having selective permeabilities. To improve selectivity, the membranes may be subjected to chemical or electrochemical treatment with electron donors or acceptors to alter the doping level of the polymer membrane, generally in a reversible fashion. This leads to significant changes in gas permeation rates relative to what is observed for the non-doped, fully dense polymers. This change in doping level of the polymer films can be precisely controlled by varying the concentration and nature of chemical dopants used. Desirable changes in permeation rates are achieved by a treatment which comprises a reversal doping of the polymeric material, followed by removal of the dopants (to provide an "undoped" polymer).

Abstract: A decoding arrangement for decoding audio signals previously encoded in accordance with the dbx format, includes a wideband expander instead of a full dbx expander. The wideband expander employs a relatively simple, and therefore inexpensive, peak detector in place of the true RMS detector of a full dbx expander, and does not include apparatus for spectral expansion of the audio signal. Although the decoding is noncomplementary with respect to the encoding, the stereo audio reproduction as perceived by a listener, is surprisingly good.

Abstract: In a television receiver, employing both a beam scan velocity modulation (SVM) system and an on screen display (OSD) generator, the OSD generator selectively operates to produce characters or graphics which are superimposed on the main video picture display. During operation of the OSD generator, the SVM circuit may tend to undesirably introduce artifacts into the picture display. Circuitry is provided for selectively disabling normal SVM circuit operation during OSD operation to prevent or reduce the perception of such artifacts.

Abstract: A combined RFI filter and low pass filter includes two sections, both of which serve as both radio frequency interference filters and low pass filters, or dc integrators. Both sections have substantially equal time constants and employ non-polarized capacitors.

Abstract: An audio/video signal switching system permits an audio input to be automatically switched from a mode in which it receives audio signals associated with an NTSC signal source, to a mode in which it receives audio signals associated with an S-VIDEO signal source.

Abstract: Apparatus for the treatment of fluids comprising a vessel containing a fixed bed of particulate material in which a plurality of fluid distribution baskets are suspended from the interior of the upper portion of the vessel and are partially submerged beneath the upper surface of the fixed bed of particulate material. Apparatus is disclosed for mutually securing the lower end portions of the fluid distribution baskets as well as preventing the flotation of the fluid distribution baskets on the surface of the particulate materials during charging of the vessel.

Abstract: A system for preventing crosstalk in a stereo television receiver includes a signal selection switch for selecting between signals produced by a demodulator and signals received at an auxiliary input, a controller for generating a switching control signal and circuitry for muting the audio demodulator during channel change and when said auxiliary input is selected in response to said switching control signal.

Abstract: A stereo expansion circuit selection switch includes a transmission gate to cross couple the right and left channels as needed for stereo expansion.

Abstract: A television receiver has provisions for a second audio program (SAP) and an indication for signifying when the SAP is present and a muting circuit for muting the SAP, both in response to the output signal of a SAP detector. A filter capacitor is coupled to the detector output to prevent flicker of the indicator due to noise. To prevent the filter capacitor from incorrectly maintaining an indication of the presence of a SAP, thereby preventing proper SAP muting, when a new channel is selected, channel change signal causes a semiconductor switch to discharge the filter capacitor.