GB1473106A - Improvements in or relating to television camera arrangements - Google Patents

Abstract

1473106 Amplifying circuit EMI Ltd 5 Aug 1974 [11 Aug 1973] 38152/73 Heading H3W A television camera arrangement includes a pick up tube coupled to a head amplifier 1 by reactive components which form a filter for the output signals from the tube, the reactive components having a resonant frequency embraced within the pass band of the filter, the pass band being defined by the frequencies where the amplitude response is 3 db down. In practice Cc and Ca are stray capacitances at the output and input of the tube and amplifier respectively with L the added component. A feedback path 2 may be provided around the amplifier 1 with signals coupled into the input path to the amplifier in a sense which tends to reduce the effective inductance as seen by the signals thereby causing a filter characteristic imposed by the effective inductance and the capacitances to embrace within its pass band the resonant frequency of the unmodified inductor and capacitances. The coupling means can be a ferrite cored transformer T, and may be a current transformer (not shown) with its primary winding in a second feedback path around a second amplifier 2 in the first feedback path. The first feedback path may have an amplifier 2 and inductor C 1 connected in parallel. The inductor 1 and transformer secondary may be combined as one component.