Analog compensation-based temperature compensation high-frequency crystal oscillator

Abstract

The invention discloses an analog compensation-based temperature compensation high-frequency crystal oscillator, wherein a closed-loop feedback compensation framework is adopted. The output signals of a voltage-controlled crystal oscillator are divided into two paths by a power divider, wherein one path of signals is input into a frequency deviation calculation module. The frequency deviation calculation module calculates to obtain a frequency deviation between the frequency of the non-compensated voltage-controlled crystal oscillator and a desired target frequency. A frequency-voltage conversion module is provided with an analog circuit, and a compensation voltage is obtained according to the frequency deviation. After that, the signal of the compensation voltage is filtered by a filter and then is fed back to the compensation voltage signal input end of the voltage-controlled crystal oscillator for compensation. Therefore, the voltage-controlled crystal oscillator outputs the target frequency which is expected to be obtained. According to the invention, no temperature sensor is required. Meanwhile, the frequency deviation related to the temperature in real time is directly converted into the compensation voltage which is in one-to-one correspondence mapping relation with the frequency deviation for carrying out the temperature compensation. Therefore, the temperature hysteresis problem during the existing temperature compensation process of the high-frequency crystal oscillator is solved.

Description

technical field [0001] The invention belongs to the technical field of crystal oscillators, and more specifically relates to a temperature-compensated crystal oscillator based on analog compensation. Background technique [0002] Temperature Compensated Crystal Oscillator (TCXO, Temperature Compensate Xtal (crystal) Oscillator) is a kind of crystal oscillator that can work in a wide temperature range and maintain the output frequency of the crystal oscillator within a certain accuracy range (10 -6 ~10 -7 order of magnitude) crystal oscillator. It has the characteristics of low power, can work immediately after starting up, and has high stability. It is widely used in various communications, navigation, radar, satellite positioning systems, mobile communications, program-controlled telephone exchanges, and various electronic measuring instruments. [0003] The existing temperature-compensated crystal oscillator is essentially a voltage-controlled crystal oscillator (Voltage...

AI Technical Summary

Problems solved by technology

The structure of the temperature compensated crystal oscillator in this way is complicated, and large-scale circuit integration can be used, and the cost is relatively high.

In addition, the analog temperature-compensated crystal oscillator implemented in this way also adopts an open-loop compensation method, which requires a separate temperature sensor to sense the external environment temperature, so that there is inevitably a temperature difference and temperature hysteresis effect between the sensor and the crystal. So that the compensation accuracy is affected

[0016] To sum up, the existing temperature-compensated crystal oscillators, namely TCXO, all adopt an open-loop compensation architecture, and temperature sensing is used. The temperature sensor is as close as possible to the crystal resonator on the circuit, and the crystal resonator The resonant chip is individually packaged in a closed space, which inevitably produces a temperature hysteresis between the temperature sensor and the resonant chip, resulting in a failure to achieve a breakthrough in the frequency-temperature characteristics of the temperature-compensated crystal oscillator.

Especially for crystal oscillators with high-frequency output signals, this temperature hysteresis problem is more obvious, which seriously restricts the frequency compensation accuracy of temperature-compensated high-frequency crystal oscillators

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