nature of the collapsed building. They DIRECTIONAL COUPLER2(3dB) : are One output of the 3 dB 1. L or S band frequency say 1150 MHZ directional coupler2 (20mW) drives the 2. UHF band frequency say clutter cancellation unit. Other output 450 MHZ. Let us see the advantages and serves as a local reference signal for the disadvantages of both the systems later. double balanced mixer. Schematic diagram of the microwave ANTENNA SYSTEM : life-detection system The dual antenna system has two antenna, which are energized sequentially an electronic switch. Each The circuit description is as follows: antenna acts separately. PHASE LOCKED OSCILLATOR: CLUTTER CANCELLATION UNIT: The phase locked oscillator The clutter cancellation unit consists of generates a very stable electromagnetic A digitally controlled phase wave say 1150 MHZ with output power shifter I say 400 mW. A fixed attenuator A RF amplifier DIRECTIONAL COUPLER 1(10 DB): A digitally controlled attenuator This wave is then fed WORKING: CLUTTER CANCELLATION OF through a 10 dB directional coupler and THE RECEIVED SIGNAL: a circulator before reaching a radio The wave radiated by the antenna frequency switch , which energizes the I penetrates the earthquake rubble dual antenna system. Also, the ten dB to reach the buried person . directional coupler branches out The reflected wave received by of the wave (40 mW ) which is the antenna2 consists of a large then divided equally by a directional reflected wave from the rubble and coupler2(3dB). a small reflected wave from the
nature of the collapsed building. They are 1. L or S band frequency say 1150 MHZ 2. UHF band frequency say 450 MHZ. Let us see the advantages and disadvantages of both the systems later. Schematic diagram of the microwave life-detection system The circuit description is as follows: PHASE LOCKED OSCILLATOR: The phase locked oscillator generates a very stable electromagnetic wave say 1150 MHZ with output power say 400 mW. DIRECTIONAL COUPLER 1(10 DB): This wave is then fed through a 10 dB directional coupler and a circulator before reaching a radio frequency switch , which energizes the dual antenna system. Also, the ten dB directional coupler branches out of the wave (40 mW ) which is then divided equally by a directional coupler2(3dB). DIRECTIONAL COUPLER2(3dB) : One output of the 3 dB directional coupler2 (20mW) drives the clutter cancellation unit. Other output serves as a local reference signal for the double balanced mixer. ANTENNA SYSTEM : The dual antenna system has two antenna, which are energized sequentially an electronic switch. Each antenna acts separately. CLUTTER CANCELLATION UNIT: The clutter cancellation unit consists of A digitally controlled phase shifter I A fixed attenuator A RF amplifier A digitally controlled attenuator WORKING: CLUTTER CANCELLATION OF THE RECEIVED SIGNAL: The wave radiated by the antenna I penetrates the earthquake rubble to reach the buried person . The reflected wave received by the antenna2 consists of a large reflected wave from the rubble and a small reflected wave from the
217172596-Embedded-System-life-Saving-Us.docx