A clock frequency supply device includes: a frequency tuner configured to receive an input signal with a carrier frequency, and tune an oscillation frequency of an oscillator based on the carrier frequency; an injector configured to inject the input signal directly into the oscillator after the tuning of the oscillation frequency is completed; and an oscillator configured to generate a reference clock signal with a reference clock frequency based on the injected input signal.

A circuit for calibrating an injection locked oscillator is provided. The injection locked oscillator includes an injection locking input, an LC tank and an oscillator output to output an oscillator output signal. The circuit is configured to adjust a capacitance of the LC tank to different values, detect an amplitude of the oscillator output signal for each value of the different values of the capacitance while an input signal having a target frequency is applied to the injection locking input, determine a maximum amplitude of the detected amplitudes, and select a value for operating the injection locked oscillator based on the determined maximum amplitude.

An oscillator calibration circuit is provided. The oscillator calibration circuit includes a signal frequency detector for producing a reference signal from a received over-the-air signal detecting a frequency of the over-the-air signal; and a first frequency locking circuit (FLC) coupled to the signal frequency detector and to a first oscillator, wherein the first FLC calibrates the frequency of the first oscillator using the reference signal to a radio frequency (RF) carrier frequency, wherein the reference signal is utilized for calibrating the first oscillator based on the frequency of the detected over-the-air signal.

A clock frequency supply device includes: a frequency tuner configured to receive an input signal with a carrier frequency, and tune an oscillation frequency of an oscillator based on the carrier frequency; an injector configured to inject the input signal directly into the oscillator after the tuning of the oscillation frequency is completed; and an oscillator configured to generate a reference clock signal with a reference clock frequency based on the injected input signal.

A circuit for calibrating an injection locked oscillator is provided. The injection locked oscillator includes an injection locking input, an LC tank and an oscillator output to output an oscillator output signal. The circuit is configured to adjust a capacitance of the LC tank to different values, detect an amplitude of the oscillator output signal for each value of the different values of the capacitance while an input signal having a target frequency is applied to the injection locking input, determine a maximum amplitude of the detected amplitudes, and select a value for operating the injection locked oscillator based on the determined maximum amplitude.

An oscillator calibration circuit is provided. The oscillator calibration circuit includes a signal frequency detector for producing a reference signal from a received over-the-air signal detecting a frequency of the over-the-air signal; and a first frequency locking circuit (FLC) coupled to the signal frequency detector and to a first oscillator, wherein the first FLC calibrates the frequency of the first oscillator using the reference signal to a radio frequency (RF) carrier frequency, wherein the reference signal is utilized for calibrating the first oscillator based on the frequency of the detected over-the-air signal.

This invention provides a mobile terminal and a network searching method for overcoming crystal aging issue. The method includes the step of: searching network by invoking parameters stored in a first area of a volatile RAM; if the searching is failed, searching network by invoking parameters stored in a second area of the volatile RAM; if the searching is failed and the number of network searches is larger than a first predetermined value, reacquiring parameters and searching network; if the searching is succeeded, updating the parameters in the first area with the reacquired parameters. By this method, the invention can effectively solve the problems caused by crystal aging or defective crystals, and increases the robustness of the network searching.

This invention provides a mobile terminal and a network searching method for overcoming crystal aging issue. The method includes the step of: searching network by invoking parameters stored in a first area of a volatile RAM; if the searching is failed, searching network by invoking parameters stored in a second area of the volatile RAM; if the searching is failed and the number of network searches is larger than a first predetermined value, reacquiring parameters and searching network; if the searching is succeeded, updating the parameters in the first area with the reacquired parameters. By this method, the invention can effectively solve the problems caused by crystal aging or defective crystals, and increases the robustness of the network searching.

A frequency adjustment device 10 includes an operation unit 14 that inputs data for a first minimum value and a first maximum value indicating a target range of a characteristic value, a fine adjustment mark display unit 24 that displays a frequency value with a first mark for fine adjustment at a position relative to a first axis which extends from a first minimum value to a first maximum value, a coarse adjustment mark display unit 22 that displays the frequency value with a second mark for coarse adjustment at a position relative to a second axis which extends from a second minimum value to a second maximum value, and a medium adjustment mark display unit 23 that displays the frequency value with a third mark for medium adjustment at a position relative to a third axis which extends from a third minimum value to a third maximum value.