| 摘要 |
FIELD: physics, signalling.SUBSTANCE: invention relates to fire safety and can be used to detect fire at early stages of smouldering and ignition of combustible materials. The device for early detection of fire comprises n gas sensors 1.j (j=1, 2, ?, n), matching amplifiers 2.j, analogue-to-digital converters 3.j, a microprocessor 4, a light and audio alarm signal generator 5, a light signalling device 6, an audio signalling device 7, an output 8 of the generator 5, connected to a central fire safety hub, a modulating code generator 9, a carrier frequency synthesizer 10, a phase-shift modulator 11, a power amplifier 12, a transmitting antenna 13, a first synchroniser 26 and a first pseudo-random sequence generator 27. A device for receiving composite phase-shift keyed PROFR signals, located at the fire department and/or monitoring station, comprises a receiving antenna 14, a high-frequency amplifier 15, a heterodyne frequency synthesizer 16, a mixer 17, an intermediate frequency amplifier 18, a phase halver 19, first 20 and second 22 narrow-band filters, a phase doubler 21, a 90° phase changer 23, a phase detector 24, a recording unit 25, a second synchroniser 28, a second pseudo-random sequence generator 29.EFFECT: high noise immunity and reliability of transmitting alarm information from fire safety facilities to the fire department and/or monitoring station via pseudorandom operational frequency readjustment of the composite phase-shift keyed signals used.2 cl, 6 dwg |
