Radio equipment based on AFC system with temperature detection and method of automatic frequency control
AssigneeUniden Corporation
InventorsYoshikazu Kurisu, Yojiro Tagawa, Ping Huang
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Abstract
Radio equipment based on an AFC system comprising a local oscillator, a reference frequency oscillator, a receiver, a frequency comparator, an AFC controller, a temperature detection sensor, and a memory. The AFC controller inputting, when starting AFC, reads out a control frequency corresponding to the detected temperature inputted thereinto to control the reference frequency for the reference frequency oscillator. When a lock signal is inputted thereinto, the detected temperature and control frequency are stored in a memory.
Claims17
Radio equipment based on AFC system comprising:
- a local oscillator which oscillates at a local frequency used for generation of an IF signal;
- a reference frequency oscillator which outputs a reference frequency to said local oscillator;
- a receiver which receives an input signal from an antenna and which mixes the frequency from said local oscillator with said received input signal and outputs said IF signal;
- a temperature detection sensor which detects a temperature value related to said reference frequency oscillator;
- a memory for storing entries comprising a value of said reference frequency and a corresponding temperature value detected by said temperature detection sensor therein;
- a frequency comparator adapted to detect a pilot signal from a base station in said IF signal and to output an unlock signal or a lock signal according to whether a pilot signal is detected;
- an AFC controller which locks the reference frequency when said pilot signal is detected or changes the reference frequency in accordance with said temperature value when said pilot signal is not detected.
In radio equipment including a base station and a remote station having a local oscillator, an automatic frequency control system comprising:
- a reference frequency oscillator for generating a reference frequency signal to control said local oscillator;
- a temperature detector responsive to said reference frequency oscillator for generating a temperature signal indicative of a temperature of said reference frequency oscillator;
- a controller responsive to said temperature signal and a related corresponding reference frequency signal for controlling said frequency oscillator immediately after said radio equipment is provided with power;
- and
- a frequency comparator for supplying said controller with an unlock signal to adjust said reference frequency oscillator in accordance with said temperature signal when a pilot frequency control signal from said base station is not detected by said radio equipment, and for supplying said controller with a lock signal to lock said reference frequency oscillator when said pilot frequency control signal is detected.
In a radio equipment including a base station and a remote station having a local oscillator controlled by a reference frequency supplied by a reference frequency oscillator, a method of automatic frequency control comprising the steps of:
- detecting a temperature of said reference frequency oscillator with a temperature detector;
- detecting a pilot frequency control signal provided by said base station;
- if said pilot frequency control signal is detected, locking the reference frequency and supplying a control value applied to the reference frequency oscillator and a detected temperature to a memory;
- and
- if said pilot frequency control signal is not detected, controlling the reference frequency in accordance with the control value stored in the memory and corresponding to the temperature detected by said temperature detector.
Dependencies are inferred from the claim text.