An exemplary apparatus includes a sensor array configured to sense a gas stream temperature, pressure, and humidity. To that end, the phase characteristic in an actually used frequency band is made substantially flat. The mounting hinge is pivotable such that the power distribution unit can be pivoted to an extended position to facilitate removal of removable modules mounted within the electronic system. The signals from the envelope detector are passed through three filters, namely, a low pass filter which passes low frequency signals in the range of 1 Hz to 40 Hz, a high pass filter which passes high frequency signals of greater than 100 Hz and a band pass filter 15 which passes intermediate frequency signals in the range of 40 Hz to 80 Hz. The printer has a front door which provides access to the inside of the housing. In the sulfidation process to produce a sour gas shift catalyst, the lower the sulfur to hydrogen molar ratio of the sulfidation feed stream, the lower the required temperature of the sulfidation feed stream.