Low noise converter employed in satellite broadcast reception system and receiver apparatus
First Claim
1. A low noise converter receiving first and second polarization signals present in a first frequency band, converting said received first and second polarization signals into first and second intermediate frequency signals, respectively, and outputting said first and second intermediate frequency signals, comprising:
- first and second local oscillation circuits providing a first local oscillation signal having a first frequency and a second local oscillation signal having a second frequency, respectively;
first and second mixer circuits mixing said first and second polarization signals with said first and second local oscillation signals, respectively, and outputting the mixed signals as third and fourth intermediate frequency signals, respectively; and
first and second signal filters passing said third and fourth intermediate frequency signals through a second frequency band and a third frequency band, respectively, said third frequency band being higher than said second frequency band, and providing the passed signals as said first and second intermediate frequency signals, respectively, wherein said first and second local oscillation circuits determine said first and second frequencies so that a frequency of n times (n is a natural number) a first frequency difference between said first and second frequencies is not present in said first to third frequency bands.
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Abstract
A reception frequency band is selected at 11.7 GHz-12.2 GHz, the local oscillating frequencies of local oscillators are determined at 10.75 GHz and 13.85 GHz, respectively, and each intermediate frequency band is selected at 950 MHz-1450 MHz and 1650 MHz-2150 MHz, respectively, so that the harmonic component of the frequency difference between local oscillation signals output from each local oscillator is not present in the frequency band of each intermediate frequency signal output from each mixer and in the reception band of polarization signals applied to input terminals.
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Citations
20 Claims
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1. A low noise converter receiving first and second polarization signals present in a first frequency band, converting said received first and second polarization signals into first and second intermediate frequency signals, respectively, and outputting said first and second intermediate frequency signals, comprising:
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first and second local oscillation circuits providing a first local oscillation signal having a first frequency and a second local oscillation signal having a second frequency, respectively;
first and second mixer circuits mixing said first and second polarization signals with said first and second local oscillation signals, respectively, and outputting the mixed signals as third and fourth intermediate frequency signals, respectively; and
first and second signal filters passing said third and fourth intermediate frequency signals through a second frequency band and a third frequency band, respectively, said third frequency band being higher than said second frequency band, and providing the passed signals as said first and second intermediate frequency signals, respectively, wherein said first and second local oscillation circuits determine said first and second frequencies so that a frequency of n times (n is a natural number) a first frequency difference between said first and second frequencies is not present in said first to third frequency bands. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A receiver apparatus comprising a low noise converter receiving first and second polarization signals present in a first frequency band, converting said received first and second polarization signals into first and second intermediate frequency signals, respectively, and outputting said first and second intermediate frequency signals, wherein said low noise converter includes:
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first and second local oscillation circuits providing a first local oscillation signal having a first frequency and a second local oscillation signal having a second frequency, respectively;
first and second mixer circuits mixing said first and second polarization signals with said first and second local oscillation signals, respectively, and outputting the mixed signals as third and fourth intermediate frequency signals, respectively; and
first and second signal filters passing said third and fourth intermediate frequency signals through a second frequency band and a third frequency band, respectively, said third frequency band being higher than said second frequency band, and providing the passed signals as said first and second intermediate frequency signals, respectively, said first and second local oscillation circuits determine said first and second frequencies so that a frequency of n times (n is a natural number) a first frequency difference between said first and second frequencies is not present in said first to third frequency bands. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification