A film for a liquid crystal display comprising a fatty acid cellulose ester film having an acetyl group and a propionyl group is disclosed. The present cell signal of each of the plurality of edge detector cells is provided to a next of the plurality of edge detector cells as the previous cell signal for the next of the plurality of edge detector cells, and the present cell signal from a last edge detector cell is provided to a first edge detector cell as the previous cell signal for the first edge detector cell. A comparator in a common-mode feedback system compares a desired amplifier output signal to one or more nodes of the amplifier.