Mobile station equipment for a mobile radio telephone system
First Claim
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1. A mobile station equipment for a mobile radio telephone system comprising:
- first frequency converting means, which includes a first local oscillator and a first mixer, for converting a radio frequency (RF) reception signal into a first intermediate frequency (IF) signal based on the output of said first local oscillator;
second frequency converting means, which includes a second local oscillator and a second mixer, for converting the first IF signal from said first frequency converting means into a second IF signal based on the output of said second local oscillator;
a voltage-controlled, temperature-compensated crystal oscillator for providing a reference frequency to at least said first local oscillator;
counting means for counting the second IF signal;
means for providing a reference value; and
computational control means which evaluates the difference of a count value of said counting means from said reference value, and provides a control signal for controlling said voltage-controlled crystal oscillator based on the evaluated difference, to said voltage-controlled crystal oscillator.
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Abstract
A mobile station equipment for a mobile radio telephone system uses a voltage-controlled, temperature-compensated crystal oscillator (VC-TCXO) as a reference oscillator for local oscillators in frequency converters which convert an RF signal into IF signals. The oscillation frequency of the VC-TCXO is controlled by counting the second IF information and evaluating its difference from a certain reference value. At reception, the local oscillators have their reference frequency stabilized based on the stable frequency information from the base station. The equipment is compact and has reduced power dissipation and lower manufacturing cost.
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10 Claims
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1. A mobile station equipment for a mobile radio telephone system comprising:
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first frequency converting means, which includes a first local oscillator and a first mixer, for converting a radio frequency (RF) reception signal into a first intermediate frequency (IF) signal based on the output of said first local oscillator; second frequency converting means, which includes a second local oscillator and a second mixer, for converting the first IF signal from said first frequency converting means into a second IF signal based on the output of said second local oscillator; a voltage-controlled, temperature-compensated crystal oscillator for providing a reference frequency to at least said first local oscillator; counting means for counting the second IF signal; means for providing a reference value; and computational control means which evaluates the difference of a count value of said counting means from said reference value, and provides a control signal for controlling said voltage-controlled crystal oscillator based on the evaluated difference, to said voltage-controlled crystal oscillator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification