Frequency stabilizing device
First Claim
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1. A frequency stabilizing device comprising:
- first detecting means for detecting a frequency error indicating the difference between an input signal and a predetermined signal;
control means for controlling an oscillation signal based on the frequency error;
second detecting means for detecting a modulated-carrier component of the input signal; and
generating means for generating a control signal to said control means in response to the detected modulated-carrier component.
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Abstract
An intermediate frequency (IF) converter converts a received signal to an IF signal. A demodulator demodulates the IF signal to a demodulated signal and detects a phase error. A frequency error detector detects a frequency error based on the phase error. A modulated-carrier detector detects a modulated carrier component from the IF signal. When the modulated carrier component is detected, a controller achieves a frequency stabilizing operation based on the frequency error.
86 Citations
18 Claims
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1. A frequency stabilizing device comprising:
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first detecting means for detecting a frequency error indicating the difference between an input signal and a predetermined signal; control means for controlling an oscillation signal based on the frequency error; second detecting means for detecting a modulated-carrier component of the input signal; and generating means for generating a control signal to said control means in response to the detected modulated-carrier component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A frequency stabilizing device comprising:
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a frequency converter for converting a frequency of a received signal to an intermediate frequency by mixing a local frequency signal; a frequency detector for detecting a frequency error indicating the difference between said intermediate signal and a predetermined signal; a controller for controlling a frequency of said local frequency signal based on the frequency error; a modulated-carrier detector for detecting a modulated-carrier component of the intermediate frequency signal; and a control signal generator for generating a control signal to said controller in response to the detected modulated-carrier component so that a frequency stabilizing operation is executed when the modulated carrier component is detected. - View Dependent Claims (12, 13, 14)
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15. A method for controlling a frequency stabilizing device, the method comprising the steps of:
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(a) detecting a frequency error indicating a difference between an input signal and a predetermined signal; (b) detecting a modulated carrier component from said input signal; (c) generating a control signal based on the detected modulated carrier component; and (d) controlling a frequency stabilizing operation based on the frequency error in response to the control signal. - View Dependent Claims (16)
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17. A method for controlling a frequency stabilizing device, the method comprising the following steps of:
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(a) converting a frequency of a received signal to an intermediate frequency by mixing with a local frequency signal; (b) demodulating the intermediated frequency signal and detecting a phase error indicating a phase difference between the demodulated signal and a predetermined signal; (c) detecting a frequency error based on the phase error; (d) detecting a received field strength from said intermediate frequency signal; (e) detecting an average of the received field strength; (f) detecting a modulated carrier component from the received field strength; (g) generating a control signal based on the detected modulated carrier component and the average of the received field strength; and (h) controlling a frequency of the local frequency signal according to the frequency error in response to the control signal. - View Dependent Claims (18)
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Specification