An Airborne Receiver for Pulsed-Light Signals.
NAVAL RESEARCH LAB WASHINGTON DC
Pagination or Media Count:
This report describes a photocell receiver which detects weak light pulses and converts them into audible notes which may be easily heard with headphones. The circuit constants are chosen so that the receiver operates with light pulses of less than 1 microsecond duration, each of which produces an oscillatory note, 1000 1200 cps, which has an on-period of 10 milliseconds. The bandwidth of the receiver is approximately 7 kc to 2.5 Mc, which is well above the frequencies of ordinary mechanical vibrations. Operation on the ordinary photomultiplier tube with a dynode voltage around 800 volts is possible under night conditions. At this dynode voltage the sensitivity at the input to the receiver is such that the input pulsed peak illumination required for triggering is only 0.005 microlumenin.sq.. The receiver operates on 115 volts at 400 cps.
- Optical Detection and Detectors