Abstract: An N.sup.th order infinite impulse response digital filter for long-delay filtering of signals representing a digital input sequence. The N.sup.th order infinite impulse response digital filter is synthesized by cascading in series N first order infinite impulse response filter stages. A filter stage operable on a digital computer with floating point capability is provided and comprises a multiplier which multiplies an input signal with a weighting factor. A summing element provides an output for the filter stage by summing the weighted input signal with a weighted and delayed output signal. A filter operable on a digital computer with fixed point capability is provided and comprises a summing element which sums an input signal with the output of a first multiplier, and the delayed output of a mask element. The output of the summing element is coupled to the input of a second multiplier and to the input of the mask element.

Abstract: Method and system for predicting air discharge temperature in a control system which controls an automotive HVAC (heating, ventilation and air conditioning) system using a model. The model is based on signals generated by various climate control sensors and actuation outputs to predict air discharge temperature without the need for an additional sensor. The model allows the avoidance of uncomfortable air discharge temperatures to thereby increase passenger comfort.