PROCESSING OF INFRARED SIGNAL

摘要

PURPOSE:To reduce a minimum detecting width without injuring an S/N and improve a resolution by resetting the differential waveform of an infrared output detected by an infrared detector when the differential value of the infrared output reaches a prescribed value. CONSTITUTION:Infrared rays radiated from the atmosphere of the earth are detected by an infrared detector 101 using a pyroelectric type infrared detecting element with a condenser lens having a high S/N and, after DC components and low frequency components are removed by a CR coupled circuit 201, ampli fied by a first stage amplifier 202 to be inputted to an equalizer 102. The output of the equalizer 102 is inputted to a differentiating circuit 203 and its differential output is inputted to a positive comparison level detector 205 and a negative comparison level detector 206 via a buffer amplifier 204. Positive and negative comparison levels are detected by the level detectors 205 and 206, respectively. A switch is operated by a pulse generated from a reset pulse generator 207 at the arrival moments of the comparison levels and a differential waveform is reset and waveform-shaped by a waveform shaper 104 whereby the edge of the earth is detected.