Upconverter for a television signal headend distribution center handling analog and digital signals and method of making and using the same
First Claim
1. An upconverter for converting an IF television signal to a VHF or UHF signal, said upconverter processing either digital or analog television signals, said upconverter comprising:
- an upconversion circuit for receiving said IF television signal and outputting a converted television signal; and
a reference signal circuit for supplying a reference signal to a modulator, said modulator being external to said upconverter, said reference signal circuit generating a first reference signal when said IF television signal is an analog signal and a second reference signal, different from said first reference signal, when said IF television signal is a digital signal.
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Accused Products
Abstract
An upconverter for converting IF television signals to VHF or UHF signals prior to broadcast is configured to process either analog or digital television signals. The upconverter identifies the type of incoming television signal and generates an appropriate reference signal depending on whether the incoming television signal is digital or analog. In an analog format, the reference signal is used by the modulator generating the IF signal to synchronize phase with the signals output by various other upconverters. In a digital format, the reference signal is used, for example, as a test signal for the upconversion circuit.
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Citations
28 Claims
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1. An upconverter for converting an IF television signal to a VHF or UHF signal, said upconverter processing either digital or analog television signals, said upconverter comprising:
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an upconversion circuit for receiving said IF television signal and outputting a converted television signal; and
a reference signal circuit for supplying a reference signal to a modulator, said modulator being external to said upconverter, said reference signal circuit generating a first reference signal when said IF television signal is an analog signal and a second reference signal, different from said first reference signal, when said IF television signal is a digital signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 22, 23, 24)
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8. A method of upconverting an IF television signal to a VHF or UHF signal regardless of whether said IF television signal is a digital signal or an analog signal, said method comprising:
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outputting a first reference signal as a reference signal when said IF television signal is an analog signal;
outputting a second reference signal as said reference signal when said IF television signal is a digital signal, said second reference signal being different from said first reference signal; and
performing said upconverting. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 25)
selectively generating said first reference signal or said second reference signal with a voltage controlled oscillator.
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10. The method of claim 9, further comprising:
controlling said voltage controlled oscillator with a phase locked loop circuit.
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11. The method of claim 10, further comprising:
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determining whether said IF television signal is a digital signal or an analog signal, and configuring said phase locked loop circuit according to whether said IF television signal is said digital signal or said analog signal.
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12. The method of claim 11, further comprising:
sampling said input television signal with said control circuit to determine whether said IF television signal is said analog signal or said digital signal.
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13. The method of claim 11, further comprising receiving, with said control circuit, a control signal indicating whether said IF television signal is a digital signal or an analog signal.
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14. The method of claim 8, further comprising:
determining whether said IF television signal is a digital signal or an analog signal and selectively providing said first reference signal or second reference signal in response.
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15. The method of claim 8, further comprising:
testing an upconversion circuit by providing said second reference signal to said upconversion circuit as a test signal.
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25. The method of claim 8, wherein said first reference signal has a frequency of 45.75 MHz when said IF television signal is said analog signal, and said second reference signal has a frequency of 44 MHz said IF television signal is said digital signal.
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16. An upconverter for converting an IF television signal to a VHF or UHF signal, said upconverter processing either digital or analog television signals, said upconverter comprising:
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an upconversion means for receiving said IF television signal and outputting a converted television signal; and
a reference signal means for supplying a reference signal, said reference signal means outputting a first reference signal when said IF television signal is an analog signal and a second reference signal when said IF television signal is a digital signal. - View Dependent Claims (17, 18, 19, 20, 21, 26, 27, 28)
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Specification