An epoxy compound of high-purity N,N,N\u2032,N\u2032-tetraglycidyl-3,4\u2032-diaminodiphenyl ether is produced by: an addition reaction step of reacting 3,4\u2032-diaminodiphenyl ether with epichloro-hydrin in a polar protic solvent at 65 to 100\xb0 C. More specifically, a circuit for detection of amplitude-shift keyed or other amplitude modulations which can be easily incorporated into an integrated circuit receiver system is described, making the receiver capable of supporting both complex IQ modulation schemes and simpler, non-coherent on-off or multiple-level keying signals. For example, if the pixel characteristic data is intensity, the dynamic range detection system detects bad pixels by identifying those pixels having an intensity value that is greater than the maximum intensity value of an adjacent pixel, or less than the minimum intensity value of an adjacent pixel. Reflected light can now escape the encapsulant, allowing for efficient emission and a broader emission profile, when compared to conventional packages with hemispheric encapsulants or lenses. Each pixel circuit comprises a charge store formed on the semiconductor substrate and a read out circuit.