Frequency synthesizer

Abstract

The invention discloses a frequency synthesizer comprising a frequency-locked loop which runs based on the reference frequency of a crystal oscillator, a frequency correction unit and an interpolation logic unit; wherein, the frequency correction unit generates a digital frequency correction control word based on a first parameter and a second parameter; the first parameter is a combination of an automatic frequency correction word and a fixed frequency control word. The interpolation logic unit is used for generating the second parameter which expresses the temperature changing compensation; wherein, when the first parameter is a constant, the frequency-locked loop generates a fixed clock signal or when the first parameter is a binary sequence which expresses the frequency changing of a modulating signal, the frequency-locked loop generates a frequency modulating signal; temperature compensation to the frequency excursion of a reference clock can be realized by controlling the frequency correction control word.

Description

technical field [0001] The invention relates to the field of electronic circuit design, in particular to a compensation technology for temperature frequency drift of a frequency synthesizer. technical background [0002] In order to ensure that all electronic devices work properly or synchronously, it is very important to provide accurate clock signals in electronic circuit design. Usually, the clock signal is generated by a crystal oscillator, wherein the crystal oscillator is an electronic circuit that utilizes the mechanical resonance of an oscillating crystal of piezoelectric material to generate an electrical signal of a certain frequency. This frequency is often used for timekeeping (such as in a quartz watch), it can also be used to provide a clock signal for a digital integrated circuit, and it can also be used to stabilize the frequency of a wireless transmitter / receiver. One cause of a clock signal that differs from design is temperature, which can affect the oper...

AI Technical Summary

Problems solved by technology

[0006] However, such a voltage-controlled temperature-compensated crystal oscillator first requires a high-quality crystal to meet the three-level linear compensation requirement, and such a high-quality crystal is very expensive, especially a small-sized crystal

It is also difficult to guarantee high-frequency stability and accuracy due to the limitation of the maximum output frequency of the crystal oscillator

In addition, the voltage-controlled temperature-compensated crystal oscillator is difficult to control small frequency changes (eg, less than 1.0 Hz) because it is difficult to accurately generate microvolt-level analog voltages.

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