The invention relates to pyroelectric vidicons.
The performance of a pyroelectric vidicon (PEV) is, like an video component, determined, in part, by the signal-to-noise ratio (S/N). The increase of the signal or the reduction of noise results in better performance. The noise in the PEV is principally from three sources. These are the preamplifier, the pedestal, and the target. The respective magnitudes of these noises, for a 4 MHz bandwidth, are:
i.sub.PA =1.5 nA rms (preamp noise) PA1 i.sub.PN =0.5 nA rms (pedestal noise) PA1 i.sub.TN =0.04 nA rms (target noise)
The preamplifier noise dominates but the pedestal noise is of the same order of magnitude. Thus, if amplification were used so that the signal is made larger than the preamplifier noise, but the pedestal noise were not eliminated, little gain in the signal to noise ratio would result. Although the pedestal noise depends on the means of pedestal generation, all methods of pedestal generation give rise to appreciable random noise.