Circuit arrangement for generating tuning voltage
First Claim
1. A circuit arrangement for use in controlling a voltage controlled tuning device of a broadcast receiver, said circuit arrangement being adapted to apply a tuning voltage to the tuning device wherein, when the tuning voltage is varied continuously from a lower to an upper limit, the frequency of the tuning device varies continuously over a tuning range which includes all channels from a first lower frequency channel of a first wavelength up to a second higher frequency channel of a second higher wavelength and including an intermediate range of undesired channels whose wavelengths are located between said first lower and said second upper wavelength and in order to prevent reception of said undesired channels, said circuit arrangement including:
- first means for producing all tuning voltages between said upper and lower limits including those tuning voltages corresponding to said undesired channels whose frequencies lie in said intermediate range;
analyzing circuit means responsive to said first means for generating a control signal when the tuning voltage developed by said first means reaches at least a predetermined value; and
third circuit means responsive to said control signal for altering the tuning voltage appearing at the output of said first means by a predetermined amount to thereby abruptly skip the tuning voltages representing said undesired channels.
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Accused Products
Abstract
The invention relates to broadcast receivers having a voltage controlled tuning device and in particular to a circuit arrangement for applying a voltage to the tuning device. The circuit arrangement is so designed as to be capable of producing tuning voltages to tune the receiver into the desired channels but at the same time being inhibited from producing voltages which tune the receiver into undesired channels such as police channels.
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Citations
12 Claims
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1. A circuit arrangement for use in controlling a voltage controlled tuning device of a broadcast receiver, said circuit arrangement being adapted to apply a tuning voltage to the tuning device wherein, when the tuning voltage is varied continuously from a lower to an upper limit, the frequency of the tuning device varies continuously over a tuning range which includes all channels from a first lower frequency channel of a first wavelength up to a second higher frequency channel of a second higher wavelength and including an intermediate range of undesired channels whose wavelengths are located between said first lower and said second upper wavelength and in order to prevent reception of said undesired channels, said circuit arrangement including:
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first means for producing all tuning voltages between said upper and lower limits including those tuning voltages corresponding to said undesired channels whose frequencies lie in said intermediate range; analyzing circuit means responsive to said first means for generating a control signal when the tuning voltage developed by said first means reaches at least a predetermined value; and third circuit means responsive to said control signal for altering the tuning voltage appearing at the output of said first means by a predetermined amount to thereby abruptly skip the tuning voltages representing said undesired channels.
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2. A circuit arrangement for applying a tuning voltage to a tuning device of a broadcast receiver, which comprises:
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first means for producing a variable voltage wherein, when the tuning voltage is varied continuously from a lower to an upper limit, the frequency of the tuning device varies continuously over a tuning range which includes all channels from a first lower frequency channel of a first wavelength and a second higher frequency channel of a second wavelength and including an intermediate range of undesired channels whose wavelengths lie between said first and second wavelengths; an analyzing circuit for detecting when the voltage at the output of said first means attains at least a predetermined value; and an alteration circuit responsive to said analyzing circuit for altering the output voltage developed by said first means by a predetermined amount so that the circuit arrangement is precluded from producing voltages representing said undesired channels. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification