NONLINEAR ANALOGUE-DIGITAL CONVERTING CIRCUIT

摘要

PURPOSE:To obtain information effective for diagnosis, by clarifying information included in the signal from a strong reflection part and its boundaries by using the output of a bias circuit as a reference input of an analogue-digital converting circuit. CONSTITUTION:A part of a video signal d0 detected by a detecting circuit 4 has DC components eliminated by a high-frequency stop filter 16, and a signal d1 which is outputted after attenuation of high frequency components is added to a constant bias voltage 20 analogically, and an output signal d3 is sent as a reference voltage VRT of an analogue-digital converting circuit 18. The analogue signal subjected to analogue-digital conversion is transmitted as an analogue signal d4 again through a storage circuit 6 and a D/A converting circuit 7. Since the rise of the video signal is emphasized in this obtained signal waveform, detailed information buried in a strong reflection signal are clarified.