COMPOSITE TUNER CAPABLE OF PREVENTING MUTUAL INTERFERENCE BETWEEN TERRESTRIAL BROADCAST AND SATELLITE BROADCAST
First Claim
1. A composite tuner employed in a broadcast receiver that can receive a terrestrial broadcast and a satellite broadcast, comprising:
- a terrestrial broadcast tuner unit frequency-converting a terrestrial broadcast signal to a first signal having a frequency band lower than the frequency band of said terrestrial broadcast signal,a terrestrial broadcast demodulation unit receiving and demodulating said first signal from said terrestrial broadcast tuner unit,a satellite broadcast tuner unit frequency-converting a satellite broadcast signal to a second signal having a frequency band lower than the frequency band of said satellite broadcast signal,a satellite broadcast demodulation unit attaining an active state when said broadcast receiver is receiving said satellite broadcast to receive and demodulate said second signal from said satellite broadcast tuner unit, and attaining an inactive state when said broadcast receiver is not receiving said satellite broadcast, anda total gain control unit causing control such that a total gain of said satellite broadcast tuner unit is not increased as compared to the total gain in said active state when said satellite broadcast demodulation unit is in said inactive state.
1 Assignment
0 Petitions
Accused Products
Abstract
A satellite and terrestrial composite tuner includes a terrestrial broadcast tuner unit, a terrestrial broadcast demodulation unit, a satellite broadcast tuner unit, and a satellite broadcast demodulation unit. Since the satellite broadcast demodulation unit attains a power-saving mode to take an inactive state when a satellite broadcast is not received, power consumption is reduced. Further, when the satellite broadcast demodulation unit is in an inactive state, a total gain control unit suppresses increase in the total gain of the satellite broadcast tuner unit. As a result, radiation towards the terrestrial broadcast tuner unit caused by an I signal and Q signal amplified by AGC amplifiers can be suppressed.
8 Citations
9 Claims
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1. A composite tuner employed in a broadcast receiver that can receive a terrestrial broadcast and a satellite broadcast, comprising:
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a terrestrial broadcast tuner unit frequency-converting a terrestrial broadcast signal to a first signal having a frequency band lower than the frequency band of said terrestrial broadcast signal, a terrestrial broadcast demodulation unit receiving and demodulating said first signal from said terrestrial broadcast tuner unit, a satellite broadcast tuner unit frequency-converting a satellite broadcast signal to a second signal having a frequency band lower than the frequency band of said satellite broadcast signal, a satellite broadcast demodulation unit attaining an active state when said broadcast receiver is receiving said satellite broadcast to receive and demodulate said second signal from said satellite broadcast tuner unit, and attaining an inactive state when said broadcast receiver is not receiving said satellite broadcast, and a total gain control unit causing control such that a total gain of said satellite broadcast tuner unit is not increased as compared to the total gain in said active state when said satellite broadcast demodulation unit is in said inactive state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A composite tuner employed in a broadcast receiver that can receive a terrestrial broadcast and a satellite broadcast, comprising:
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a terrestrial broadcast tuner unit frequency-converting a terrestrial broadcast signal to a first signal having a frequency band lower than the frequency band of said terrestrial broadcast signal, a terrestrial broadcast demodulation unit receiving and demodulating said first signal from said terrestrial broadcast tuner unit, a satellite broadcast tuner unit frequency-converting a satellite broadcast signal to a second signal having a frequency band lower than the frequency band of said satellite broadcast signal, said satellite broadcast tuner unit including a detection circuit detecting an output level of said second signal, and an automatic gain control circuit adjusting an output level of said second signal according to a detected value of said detection circuit, and a satellite broadcast demodulation unit attaining an active state when said broadcast receiver is receiving said satellite broadcast to demodulate said second signal, and attaining an inactive state when said broadcast receiver is not receiving said satellite broadcast.
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Specification