TVRO receiver system with low-cost video-noise reduction filter
First Claim
1. A TVRO receiver for receiving frequencymodulated video signals centered within a frequency range having a nominal center frequency, the receiver comprising:
- a tuner including a superheterodyne circuit having a voltage-controlled oscillator (VCO), means for supplying a controlling input voltage to said VCO, and a mixer for combining incoming 1st IF signals within a predetermined IF frequency range with the output of said VCO to reduce the frequency of the 1st IF signals to within a 2nd IF frequency range having a predetermined nominal center frequency which permits the output frequencies of said VCO to be above the frequency range of the 1st IF signals, thereby preventing the output of the VCO from the interfering with the 1st IF signals, anda single linear phase passband filter for passing a single video channel in the 2nd IF output from said mixer, said filter having adjustable passband characteristics for producing an output which is at least about 10 dB down from its peak at both +10 MHz and -10 MHz from the center of the passband of said filter.
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Accused Products
Abstract
A TVRO receiver for receiving frequency-modulated video signals, the receiver comprising a tuner including a superheterodyne circuit having a voltage-controlled oscillator (VCO), means for supplying a controlling input voltage to the VCO, and a mixer for combining incoming 1st IF signals with the output of the VCO to reduce the frequency of the 1st IF signals to a 2nd IF frequency which is sufficiently high to permit the output frequency of the VCO to be above the frequency range of the 1st IF signals, and a linear phase passband filter for passing a single video channel in the 2nd IF output from the mixer, the filter producing an output which is at least about 10 dB down from its peak at both +10 MHz and -10 MHz from the center of the passband of the filter.
13 Citations
21 Claims
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1. A TVRO receiver for receiving frequencymodulated video signals centered within a frequency range having a nominal center frequency, the receiver comprising:
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a tuner including a superheterodyne circuit having a voltage-controlled oscillator (VCO), means for supplying a controlling input voltage to said VCO, and a mixer for combining incoming 1st IF signals within a predetermined IF frequency range with the output of said VCO to reduce the frequency of the 1st IF signals to within a 2nd IF frequency range having a predetermined nominal center frequency which permits the output frequencies of said VCO to be above the frequency range of the 1st IF signals, thereby preventing the output of the VCO from the interfering with the 1st IF signals, and a single linear phase passband filter for passing a single video channel in the 2nd IF output from said mixer, said filter having adjustable passband characteristics for producing an output which is at least about 10 dB down from its peak at both +10 MHz and -10 MHz from the center of the passband of said filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A TVRO receiver for receiving frequency-modulated video signals centered within a frequency range having a nominal center frequency, said received signals being centered at a frequency which is offset from the nominal center frequency of the signals, the receiver comprising:
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a tuner including a superheterodyne circuit having a voltage-controlled oscillator (VCO), means for supplying a controlling input voltage to said VCO, and a mixer for combining incoming 1st IF signals within a predetermined IF frequency range with the output of said VCO to reduce the frequency of the 1st IF signals to within a 2nd IF frequency range having a predetermined nominal center frequency, the resulting 2nd IF video signals being centered at a frequency which is offset from the nominal 2nd IF center frequency, and a single passband filter for passing a single video channel, means for offsetting the center frequency of the passband of said filter to be aligned with the frequency at which said 2nd IF signals are centered. - View Dependent Claims (18, 19, 20, 21)
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Specification