Frequency transformations for digital filters
It is shown that the reactance transformation for an analog filter corresponds to an all-pass function transformation in the case of a digital filter. It is further shown how this result could be used to obtain in a simple way the spectral transformations for digital filters derived by Constantinides.
High Order Transformations for Flexible IIR Filter Design
Extensions of popular transformations for IIR filters are given which employ high order mapping filters. Easy control of prototype transfer function features in multiband renditions is demonstrated. A wider interpretation of transformation is also suggested which permits "less-than-N-band replication" (at a cost in dimensionality , phase fidelity and attention to stability enforcement) that is believed to be of considerable benefit in practical design situations.
Enumeration of total coliforms, fecal coliforms, and Escherichia coli in foods by hydrophobic grid membrane filter: supplementary report.
Raw, comminuted poultry meat was used to determine the specificity of the media and incubation conditions used in the hydrophobic grid membrane filter method. Confirmation rates for target colonies were 100% for total coliforms, 98% for fecal coliforms, and 97-99% for Escherichia coli. The results of total coliform enumeration in 30 pasteurized milk samples by both the hydrophobic grid membrane filter method and AOAC method 46.013-46.016 are also reported.