BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
FIG. 1 is a block diagram of an electronic endoscope according to a first embodiment of the invention.
FIGS. 2A, 2B, 2C, 2D and 2E respectively illustrate timing charts for a horizontal driving signal, a reset gate signal, an analog output signal, a black sampling signal, and an image sampling signal.
FIGS. 2F and 2G respectively illustrate timing charts of an output signal of a flip-flop of a detection circuit for a black sampling signal, and an output signal of a flip-flop of a detection circuit for an image sampling signal.
FIG. 3 is a circuit diagram of an abnormal state detection circuit provided in a programmable IC according to the first embodiment.
FIG. 4 shows a truth table of a flip-flop provided in the abnormal state detection circuit.
FIG. 5 is a circuit diagram of an abnormal state detection circuit provided in a programmable IC according to a second embodiment.
FIGS. 6A, 6B, 6C and 6D show examples of signals generated in the abnormal state detection circuit shown in FIG. 5 when driving and sampling signals in a normal state are inputted to the abnormal state detection circuit.
FIGS. 7A, 7B, 7C, 7D and 7E are timing charts respectively illustrating a horizontal driving signal, a reset gate signal, an analog output signal, a black sampling signal, and an image sampling signal, for explaining a case where each of the black sampling signal and the image sampling signal is in an abnormal state.
FIGS. 8A, 8B, 8C and SD show examples of signals generated in the abnormal state detection circuit shown in FIG. 5 when the driving and sampling signals in the abnormal state shown in FIGS. 7A to 7E are inputted to the abnormal state detection circuit.
FIG. 9 is a circuit diagram illustrating an example of the driving signal state detection circuit.