| The functions performed by repeaters are
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| | attenuation and distortion. Present
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| amplification and frequency down
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| | communication satellite repeaters use dual
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| conversion. Repeater amplifies signal from
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| | mode filters using cavity coupling and
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| a low power level of the order of negative
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| | having centre frequency to bandwidth ratio
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| hundred decibels watt to an output power
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| | of about 100000 and C band and about 10000
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| level of the order of ten decibel watts
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| | at about k band. Accordingly C band filter
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| thus providing again of the order of
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| | has bandwidth of about thirty six mega
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| hundred and ten decibel. Frequency down
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| | hertz.
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| conversion avoids interference between
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| | Primary function of carrier processing
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| strong transmitted signals and weak
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| | equipment is frequency translation that is
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| returning signal sometimes these repeaters
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| | to bring the uplink signal to lower
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| perform the additional function of
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| | frequency down link signal. Frequency
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| detection or demodulation then the
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| | translation can be done in the following
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| repeater or the transponder is called
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| | four different ways. Conventional repeater
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| regenerative transponder.
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| | use either radio frequency-radio frequency
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| Parts of a typical satellite repeater are
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| | translation or radio frequency-
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| satellite antenna, diplexer, front end
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| | Intermediate frequency-radio frequency
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| electronic system, carrier processing
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| | translation where as regenerative repeater
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| system and power amplifier. In diplexer
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| | uses either intermediate frequency
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| the same antenna is being used by the
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| | modulation method or demodulation-re
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| satellite for receiving the uplink signal
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| | modulation method. Thus the difference in
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| and transmitting the downlink signal. This
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| | the conventional repeater and regenerative
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| is made possible by use of an electronic
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| | repeater lies only in the structure of its
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| device called diplexer which serves a two
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| | carrier processing unit. Last unit of the
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| way microwave gate. Since two different
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| | satellite is the power amplifier.
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| frequencies are used for uplink and down
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| | Traveling wave tube amplifiers re
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| link there is no interference between the
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| | popularly used as power amplifiers. The
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| two transmissions and the same antenna
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| | size of traveling wave tube depends upon
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| serves satisfactorily. Front end
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| | the purpose of the satellite. Typical
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| electronic system is made up of radio
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| | parameters of traveling wave tube
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| frequency filter, equalizer and low noise
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| | amplifiers are saturated output power is
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| amplifier. Signal from the diplexer is
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| | eight to twenty watts, saturated gain is
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| fed to the radio frequency filter. It is
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| | fifty five decibel, carrier to inter
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| an integrated circuit microwave filter
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| | modulation noise power ratio at saturation
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| having merits of better packaging, smaller
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| | is ten to twelve decibel and amplitude
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| weight and lesser power requirements. This
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| | modulation-pulse modulation conversion
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| filter is designed to achieve requisite
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| | coefficient is 4.5 decibels.
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| mask, noise rejection and equalization. It
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| | Tymon Hytem has worked in the electronics
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| should not add any circuit noise.
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| | feild for the past 15 years. He enjoys
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| Typical filters so used are Butterworth,
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| | helping people decide on electronic
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| Cheby Chev or Bessel filters. The delay
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| | gadgets from telephones to XM Radio and
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| introduced by the filter is cancelled by
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| | choosing the perfect XM Satellite Radio
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| an equalizer without introducing any
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| | system for their needs.
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