Radio receiver with improved channel selection and reception
First Claim
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1. An RF amplifying circuit for a receiver for amplifying an incoming radio frequency signal from an antenna, comprising:
- means for amplifying the incoming radio frequency signal,first gain controlling means coupled to the output of said amplifying means for controlling the level of an output signal from said amplifying means,second gain controlling means coupled to the output of said amplifying means for controlling the level of an output signal from said amplifying means,tuning means coupled to the output of said first gain controlling means for extracting a narrow band RF signal including a desired frequency region from said incoming radio frequency signal,first means coupled to the output of said second gain controlling means for generating a wide band RF signal from said incoming radio frequency signal,control means responsive to a channel selecting instruction for setting said first and second gain controlling means in opposite operational states, andselection means responsive to the output of said control means for selectively passing one of said narrow band RF signal and said wide band RF signal to down-stream circuitry, said selection means passing said wide band RF signal during a channel selection and passing said narrow band RF signal after the completion of the channel selection.
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Abstract
A radio receiver responsive to a received RF signal containing a plurality of channel frequencies each having broadcast information which includes a circuit for producing a wide band version of the received RF signal and a circuit for producing a narrow band version of the received RF signal. Selection of a channel at a given frequency is accomplished by using the wide band version of the received RF signal and after such selection is made, the narrow band version of the signal is used for further reception of the selected channel frequency and reproduction of the information thereon.
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Citations
13 Claims
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1. An RF amplifying circuit for a receiver for amplifying an incoming radio frequency signal from an antenna, comprising:
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means for amplifying the incoming radio frequency signal, first gain controlling means coupled to the output of said amplifying means for controlling the level of an output signal from said amplifying means, second gain controlling means coupled to the output of said amplifying means for controlling the level of an output signal from said amplifying means, tuning means coupled to the output of said first gain controlling means for extracting a narrow band RF signal including a desired frequency region from said incoming radio frequency signal, first means coupled to the output of said second gain controlling means for generating a wide band RF signal from said incoming radio frequency signal, control means responsive to a channel selecting instruction for setting said first and second gain controlling means in opposite operational states, and selection means responsive to the output of said control means for selectively passing one of said narrow band RF signal and said wide band RF signal to down-stream circuitry, said selection means passing said wide band RF signal during a channel selection and passing said narrow band RF signal after the completion of the channel selection. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A radio receiver for reproducing a radio signal of a desired channel from an incoming radio frequency signal from an antenna, comprising:
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RF tuning means for generating a narrow band RF signal having a band tuned to a frequency of a desired channel from said incoming radio signal, said RF tuning means including a control input and being responsive to a control signal applied to said control input for setting a frequency of said narrow band RF signal, means for generating a wide band RF signal from said incoming radio frequency signal, said wide band RF signal having a band at least covering all the bands of the narrow band RF signal which said RF tuning means can generate, first channel selecting means responsive to a channel selecting instruction for carrying out a channel section by utilizing said wide band RF signal, and second channel selecting means responsive to a completion of the channel selecting operation of said first channel selecting means for establishing the channel frequency selected by said first channel selecting means in said RF tuning means and for adjusting said established channel frequency by utilizing the narrow band RF signal from said RF tuning means, said second channel selecting means operable in a fine tuning mode wherein said established channel frequency is fine-tuned and in a reception mode wherein the tuning frequency tuned in said fine tuning mode is continuously kept, and including means for generating a tuning frequency control signal for controlling the frequency of the narrow band RF signal from said RF tuning means, filtering means for filtering said tuning frequency control signal and transmitting the filtered signal to said control input of said RF tuning means, said filtering means having at least a first time constant and a second time constant larger than said first time constant, and time constant setting means for setting said time constant of said filtering means to either said first or second time constant in accordance with the operation mode of said second channel selecting means. - View Dependent Claims (12, 13)
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Specification