Tuner circuit
First Claim
1. A circuit module for processing a radio frequency broadcast signal, comprising:
- an input terminal configured to receive said radio frequency broadcast signal;
a tuner circuit in operable connection with said input terminal to receive said radio frequency broadcast signal therefrom, said tuner circuit being configured to convert said received radio frequency broadcast signal into at least an intermediate frequency signal;
a filter in communication with said tuner circuit to receive said intermediate frequency signal therefrom, said filter being configured to define frequency characteristics of said intermediate frequency signal to produce a frequency characteristics defined intermediate frequency signal;
a demodulator in communication with said filter to receive said frequency characteristics defined intermediate frequency signal therefrom, said demodulator being configured to produce at least a video signal based on said frequency characteristics defined intermediate frequency signal; and
an output terminal in communication with said demodulator to receive said video signal therefrom, said output terminal being configured to output said video signal at an output level to an input of an external circuit,said filter, to compensate an attenuation of a high frequency component, among the defined frequency characteristics of said frequency characteristics defined intermediate frequency signal, when said output terminal outputs said video signal to the input of said external circuit, boosts a gain of the high frequency component of said frequency characteristics defined intermediate frequency signal by a predetermined amount to compensate the attenuation, andwherein said output terminal outputs said video signal to the input of the external circuit without using an external buffer between said output terminal and said external circuit.
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Accused Products
Abstract
A tuner circuit and a method of designing a tuner circuit for removing a buffer circuit for video drive for increasing drive current capacitance added to an output terminal is provided, unlike a buffer for small-current drive installed in a tuner circuit. The method of designing a tuner circuit has a buffer installed in an integrated circuit (IC) of small-current drive in a video output terminal, and includes an RF converting portion, a tuning portion and a demodulation portion, in which a video output signal of the buffer in IC is input to an input circuit for processing a signal without an external buffer for drive, and the amount of attenuation of a signal at high frequency due to small drive current is measured to improve a frequency characteristic of a video signal in the tuner circuit in proportion to the amount of attenuation. Thus, an additional buffer for drive is not required, so that the number of devices is reduced, to thereby lower the material costs.
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Citations
33 Claims
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1. A circuit module for processing a radio frequency broadcast signal, comprising:
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an input terminal configured to receive said radio frequency broadcast signal; a tuner circuit in operable connection with said input terminal to receive said radio frequency broadcast signal therefrom, said tuner circuit being configured to convert said received radio frequency broadcast signal into at least an intermediate frequency signal; a filter in communication with said tuner circuit to receive said intermediate frequency signal therefrom, said filter being configured to define frequency characteristics of said intermediate frequency signal to produce a frequency characteristics defined intermediate frequency signal; a demodulator in communication with said filter to receive said frequency characteristics defined intermediate frequency signal therefrom, said demodulator being configured to produce at least a video signal based on said frequency characteristics defined intermediate frequency signal; and an output terminal in communication with said demodulator to receive said video signal therefrom, said output terminal being configured to output said video signal at an output level to an input of an external circuit, said filter, to compensate an attenuation of a high frequency component, among the defined frequency characteristics of said frequency characteristics defined intermediate frequency signal, when said output terminal outputs said video signal to the input of said external circuit, boosts a gain of the high frequency component of said frequency characteristics defined intermediate frequency signal by a predetermined amount to compensate the attenuation, and wherein said output terminal outputs said video signal to the input of the external circuit without using an external buffer between said output terminal and said external circuit. - View Dependent Claims (2, 3, 4)
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5. A broadcasting signal processing system comprised of a circuit module for processing a radio frequency broadcast signal, said circuit module comprising:
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an input terminal configured to receive said radio frequency broadcast signal; a tuner circuit in operable connection with said input terminal to receive said radio frequency broadcast signal therefrom, said tuner circuit being configured to convert said received radio frequency broadcast signal into at least an intermediate frequency signal; a filter in communication with said tuner circuit to receive said intermediate frequency signal therefrom, said filter being configured to define frequency characteristics of said intermediate frequency signal to produce a frequency characteristics defined intermediate frequency signal; a demodulator in communication with said filter to receive said frequency characteristics defined intermediate frequency signal therefrom, said demodulator being configured to produce at least a video signal based on said frequency characteristics defined intermediate frequency signal; an external circuit configured to receive said video signal from said demodulator at an input, said filter, to compensate an attenuation of a high frequency component, among the defined frequency characteristics of said frequency characteristics defined intermediate frequency signal, when said external circuit receives said video signal from said demodulator, boosts a gain of the high frequency component of said video signal by a predetermined amount to compensate the attenuation, and wherein said external circuit receives said video signal from said demodulator without using an external buffer between said demodulator and said external circuit. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. A tuner circuit, comprising:
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a demodulation circuit comprising an integrated circuit and configured to demodulate an intermediate frequency signal to generate a demodulated video signal, said demodulation circuit comprising; a filter configured, to compensate an attenuation of a high frequency component, among frequency characteristics of said intermediate frequency signal, when the tuner circuit outputs the demodulated video signal, to boost a gain of the high frequency component of said intermediate frequency signal by a predetermined amount to compensate for the attenuation; said tuner circuit not having a buffer external to the integrated circuit for driving the demodulated video signal. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. A system, comprising:
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a tuner circuit having a demodulation circuit comprising an integrated circuit and configured to demodulate an intermediate frequency signal to generate a demodulated video signal, said demodulation circuit comprising; a filter configured, to compensate an attenuation of a high frequency component, among frequency characteristics of the intermediate frequency signal, when an output terminal outputs the demodulated video signal, to boost a gain of the high frequency component of said intermediate frequency signal by a predetermined amount to compensate for the attenuation, and the output terminal that outputs the demodulated video signal; said tuner circuit not having a buffer external to the integrated circuit for driving the demodulated video signal.
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22. A system, comprising:
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a tuner circuit configured to generate a demodulated video signal; and an external circuit, outside of the tuner circuit, that receives the demodulated video signal from the tuner circuit without said demodulated video signal having passed through a buffer external to the integrated circuit, said external circuit having an input impedance of at least 30KΩ
to compensate for a reduction in drive current of the demodulated video signal caused by absence of a buffer external to the integrated circuit. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification