Radio book arabic

Page 29

‫اﻟﻤﺮﺷﺢ)‪ (filter‬وهﻮ ﻳﻘﻮم ﺑﺘﺮﺷﻴﺢ اﻻﺷﺎرﻩ اﻟﺮادﻳﻮﻳﻪ ﻣﻦ اى ﺗﻮاﻓﻘﻴﺎت‬ ‫ﻣﻦ اﻟﺘﺮدد ﻏﻴﺮ ﻣﺮﻏﻮب ﻓﻴﻬﺎ ﺗﺨﺮج ﻣﻊ اﺷﺎرﻩ اﻻرﺳﺎل‬ ‫اﻟﻬﻮاﺋﻰ )‪ (Antenna‬وهﻮ ﻳﻘﻮم ﺑﺎﺷﻌﺎع اﻻﺷﺎرﻩ اﻟﺮادﻳﻮﻳﻪ اﻟﻰ اﻻﺛﻴﺮ‪.‬‬ ‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬ ‫‪ -4‬ﺟﻬﺎز ارﺳﺎل ﺑﻨﻈﺎم ﺗﻌﺪﻳﻞ اﻟﺤﺰﻣﻪ اﻟﺠﺎﻧﺒﻴﻪ اﻟﻤﻔﺮدﻩ ‪(SSB‬‬ ‫)‪Transmitter‬‬

‫ﻓﻰ هﺬا اﻟﺮﺳﻢ اﻟﻤﺮﻓﻖ ﻣﺨﻄﻂ ﻟﺠﻬﺎز ارﺳﺎل ﺑﻨﻈﺎم اﻟﺤﺰﻣﻪ اﻟﺠﺎﻧﺒﻴﻪ اﻟﻤﻔﺮدﻩ ‪SSB‬‬ ‫وهﻮ ﻳﺘﻜﻮن ﻣﻦ ﺑﻌﺾ اﻻﺟﺰاء وهﻰ ‪.‬‬ ‫اﻟﻤﺬﺑﺬب)‪ (rf oscillator‬وهﻮ ﻳﻘﻮم ﺑﺘﻮﻟﻴﺪ اﻟﻤﻮﺟﻪ اﻟﺤﺎﻣﻠﻪ وآﻤﺜﻞ اى ﻣﺬﺑﺬب ﻳﺘﻜﻮن‬ ‫ﻣﻦ ﻣﻠﻒ وﻣﻜﺜﻒ او ﻣﻦ ﺑﻠﻮرﻩ آﺮﻳﺴﺘﺎﻟﻴﻪ وﻳﻤﻜﻦ ان ﻳﺮآﺐ ﺑﻌﺪ هﺬﻩ اﻟﻤﺮﺣﻠﻪ ﻣﻜﺒﺮ ﺣﺎﺟﺰ‬ ‫او ﻗﺪ ﻻﻳﺮآﺐ ﺣﺴﺐ ﺗﺼﻤﻴﻢ اﻟﺪاﺋﺮﻩ واﺣﺘﻴﺎﺟﺘﻬﺎ‬ ‫اﻟﻤﻌﺪل اﻟﻤﺘﺰن ) ‪ (balanced modulator‬وﻓﻰ هﺬا اﻟﻤﻌﺪل ﻳﺘﻢ ادﺧﺎل اﺷﺎرﻩ اﻟﻤﺬﺑﺬب‬ ‫واﺷﺎرﻩ اﻟﻤﻜﺒﺮ اﻟﺼﻮﺗﻰ ﻟﻴﻨﺘﺞ ﻓﻰ اﻟﺨﺮج اﻟﺤﺰﻣﺘﻴﻦ اﻟﺠﺎﻧﺒﻴﺘﻴﻦ ﺑﺪون اﺷﺎرﻩ اﻟﺤﺎﻣﻞ اى ﻳﺘﻢ‬ ‫ﺣﺬف اﻟﺤﺎﻣﻞ ﻧﻬﺎﺋﻴﺎ واﻟﻨﺘﻴﺠﻪ ﻳﻜﻮن ﻓﻰ اﻟﺨﺮج اﺷﺎرﻩ اﻟﺤﺰﻣﺘﻴﻦ اى )‪ (DSB‬وﻳﻤﻜﻦ ﻋﻨﺪ‬ ‫هﺬﻩ اﻟﻨﻘﻄﻪ ان ﺗﺨﺮج ﻣﺒﺎﺷﺮﻩ ﻋﻠﻰ اى ﻣﻜﺒﺮ ﺗﺮدد ﻋﺎﻟﻰ وﻳﺘﻢ ارﺳﺎﻟﻬﺎ وﻟﻜﻨﻨﺎ ﻧﺮﻳﺪ اﺷﺎرﻩ‬ ‫ﺣﺰﻣﻪ وﺣﻴﺪﻩ ﻓﻘﻂ ﻟﺬﻟﻚ ﻟﻨﺪﺧﻞ ﻋﻠﻰ اﻟﻤﺮﺣﻠﻪ اﻟﺘﻰ ﺗﻠﻴﻬﺎ وهﻰ ﻣﺮﺷﺢ اﻟﺤﺰﻣﻪ‬


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