Temperature-compensated crystal oscillator based on analog circuit

Patent metadata

Field	Value
Publication number	US-2018013384-A1
Application number	US-201715711430-A
Country	US
Kind code	A1
Filing date	Sep 21, 2017
Priority date	May 17, 2017
Publication date	Jan 11, 2018
Grant date	—

Abstract

Disclosed is a temperature-compensated crystal oscillator based on analog circuit; a closed-loop compensation architecture determines the temperature compensation of a crystal oscillator. The power splitter divides the VCXO's current output signal with frequency f=f 0 +Δf into two signals, one signal to output of the TCXO and the other signal is sent to an analog frequency-voltage conversion circuit. According to the frequency of the VCXO's current output signal, the analog frequency-voltage conversion circuit produces a voltage signal V(T), which corresponds to current ambient temperature. The difference between V(T) and a reference voltage signal V ref is produced and amplified to obtain a compensation voltage signal ΔV through a voltage matching circuit. ΔV is smoothed by a filter, then sent to the voltage control terminal of the VCXO to make the VCXO generate a stable signal with desired frequency f 0 , to compensate the frequency of the VCXO's output signal when the ambient temperature is changed.

First claim

What is claimed is:

1 . A temperature-compensated crystal oscillator based on analog circuit, comprising:
a VCXO for generating a signal with desired frequency f 0 ; wherein further comprising: a power splitter for dividing the VCXO's current output signal with frequency f=f 0 +Δf into two signals, where one signal is used as the output of the TCXO, the other signal is taken as a frequency-voltage conversion signal; an analog frequency-voltage conversion circuit for receiving the frequency-voltage conversion signal, and converting it, i.e. the VCXO's current output signal with frequency f=f 0 +Δf into a voltage signal V(T), which is proportional to the frequency f; a voltage matching circuit for receiving the voltage signal V(T), then producing the difference between the voltage signal V(T) and a reference voltage signal V ref , i.e. V ref −V(T), and amplifying the difference to obtain a compensation voltage signal ΔV; where the reference voltage signal V ref is the voltage signal converted by the frequency-voltage conversion circuit, when the VCXO is at room temperature 25° C., and generates a signal with desired frequency f 0 by adjusting the control voltage of the VCXO; a filter for smoothing the compensation voltage signal ΔV, where the smoothed compensation voltage signal ΔV is sent to the voltage control terminal of the VCXO to make the VCXO generate a stable signal with desired frequency f 0 .

2 . A temperature-compensated crystal oscillator based on analog circuit of claim 1 , wherein further comprising an adder for adding the filtered compensation voltage signal ΔV to the control voltage VC 0 , and obtaining the control voltage VC=VC 0 +ΔV; where the control voltage VC is applied to the voltage control terminal of the VCXO to make the VCXO generate a stable signal with desired frequency f 0 , so that the frequency of the VCXO's output signal is compensated, when the ambient temperature is changed.

Assignees

• Univ Electronic Sci & Tech China
• Univ Electronic Sci & Tech China

Inventors

• Tan Feng
• Qiu Duyu
• Ye Peng
• Chen Jiquan
• Guo Lianping
• Zeng Hao
• Zhang Shuo
• Tang Ke

Classifications

• H03B5/04 Primary

  Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature · CPC title

• H03B5/366

  and comprising means for varying the frequency by a variable voltage or current · CPC title

• H03L1/02 Primary

  against variations of temperature only · CPC title

• H03L7/06

  using a reference signal applied to a frequency- or phase-locked loop · CPC title

• H03L7/00

  Automatic control of frequency or phase; Synchronisation · CPC title