| CPC H03L 7/0992 (2013.01) [H03B 5/1206 (2013.01); H03B 5/1212 (2013.01); H03B 5/1228 (2013.01); H03B 5/1243 (2013.01); H03B 5/1265 (2013.01); H03L 7/085 (2013.01)] | 4 Claims |
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1. A frequency selective circuit comprising a voltage-controlled oscillator for outputting a frequency corresponding to a frequency adjustment window;
a frequency divider for dividing a clock frequency output by the voltage-controlled oscillator, and feeding back a low frequency obtained by the dividing to a frequency selective unit;
the frequency selective unit for comparing a reference frequency against the obtained low frequency output by the frequency divider, and providing a frequency adjustment window which is configured based on a frequency search window to the voltage-controlled oscillator; and
a register group for outputting the frequency search window which is provided to the frequency selective unit;
wherein the register group comprises a first register, a second register, a third register, and a fourth register, wherein the first register and the third register are used to output a third frequency search window, wherein the third frequency search window comprises at least two frequencies, wherein the frequency selective unit is used to configure the frequency adjustment window as a first frequency for the voltage-controlled oscillator according to the third frequency search window; wherein the second register and the fourth register are used to output a fourth frequency search window, wherein the fourth frequency search window comprises at least two frequencies and is different from the third frequency search window, wherein the frequency selective unit is used to configure the frequency adjustment window as a second frequency for the voltage-controlled oscillator according to the fourth frequency search window;
wherein the first register and the second register are each connected to and controlled by a first port switching unit, and wherein the third register and the fourth register are each connected to and controlled by a second port switching unit; wherein in response to each of the first and second port switching units changing from a first state to a second state, the first frequency is switched to the second frequency, and wherein frequency selective circuit is operative to switch from the first and the third registers to the second and the fourth registers.
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