CN112595890A

CN112595890A - Voltage controlled crystal oscillator frequency test system and scheme

Info

Publication number: CN112595890A
Application number: CN202011352732.9A
Authority: CN
Inventors: 唐立
Original assignee: Chengdu Hengjing Technology Co ltd
Current assignee: Chengdu Hengjing Technology Co ltd
Priority date: 2020-11-26
Filing date: 2020-11-26
Publication date: 2021-04-02
Anticipated expiration: 2040-11-26
Also published as: CN112595890B

Abstract

The invention relates to a voltage controlled crystal oscillator frequency test system, which comprises a test board body, wherein the test board body is respectively provided with a voltage controlled crystal oscillator frequency to be tested and a mark frequency source, the voltage controlled crystal oscillator frequency to be tested and the mark frequency source are phase-locked through a phase-locked loop, the phase-locked loop outputs a voltage controlled crystal oscillator which meets the requirement of a required frequency and a voltage controlled range, the phase-locked loop can be normally locked, otherwise, the phase-locked loop cannot be locked, the voltage controlled crystal oscillator test is completed according to the phase-locked result output by the phase-locked loop, a plurality of phase-locked loops are adopted on the test board, and the multipath voltage controlled crystal oscillator test is simultaneously carried out.

Description

Voltage controlled crystal oscillator frequency test system and scheme

Technical Field

The invention relates to the field of voltage-controlled crystal oscillators, in particular to a frequency test system and a frequency test scheme of a voltage-controlled crystal oscillator.

Background

The voltage-controlled crystal oscillator outputs the frequency required by a user through external frequency tuning voltage control, thereby realizing the effect of frequency synchronization between the butt joint devices. With the popularization of intelligent equipment and the internet of things, the voltage-controlled crystal oscillator is widely used, and the requirement on test screening equipment of the voltage-controlled crystal oscillator is increased.

Frequency testing is often performed on the voltage-controlled crystal oscillator by adopting frequency testing equipment (a frequency meter or a counter), the voltage-controlled crystal oscillator is tested one by a time-sharing single path, and the frequency testing equipment has the defects of higher equipment price, lower time-sharing testing efficiency and incapability of directly performing simultaneous testing on a plurality of voltage-controlled crystal oscillators in parallel.

Disclosure of Invention

The present invention is directed to overcome the above problems in the prior art, and provides a system and a method for testing a frequency of a voltage controlled crystal oscillator.

In order to achieve the technical purpose and achieve the technical effect, the invention is realized by the following technical scheme:

a voltage controlled crystal oscillator frequency test system comprises a test board body, wherein a voltage controlled crystal oscillator frequency to be tested and a mark frequency source are respectively arranged on the test board body, and the voltage controlled crystal oscillator frequency to be tested and the mark frequency source are phase-locked through a phase-locked loop.

Preferably, the phase-locked loop outputs a voltage-controlled crystal oscillator which meets the requirement of the required frequency and the voltage-controlled range, the phase-locked loop can be normally locked, otherwise, the phase-locked loop cannot be locked, and the voltage-controlled crystal oscillator test is completed according to the phase-locked loop output phase-locked result.

Preferably, the test board is provided with a plurality of phase-locked loops for simultaneously performing a multi-path voltage-controlled crystal oscillator test.

A voltage-controlled crystal oscillator frequency test scheme is characterized in that according to a phase-locked loop principle, a crystal oscillator meeting the phase-locked requirement is normally phase-locked, a standard frequency source is input, a standard clock is provided through clock sources such as a rubidium clock or a Beidou satellite, the phase-locked loop is realized, the front-end input standard frequency is processed to be the same frequency as a tested VCXO, the functional requirement of a phase-locked loop module is reduced, the phase-locked loop module does not need frequency division alignment, phase discrimination comparison is directly carried out, a test result is output to an upper computer through a test bus to be recorded, and the test.

Preferably, in the step S1, the test is performed on a voltage controlled crystal oscillator with voltage control range of ± 10ppm and a voltage controlled crystal oscillator with voltage of 9MHz, and outputs "1" which does not meet the phase locking requirement or the vacancy test path, and outputs "0", and the upper computer directly reads the test result bus to obtain the test result, and the first path of crystal oscillator passes the test.

Preferably, in step S2, the general clock source is provided at 10MHz, and if the tested VCXO is not consistent with the clock source frequency, the clock with the test frequency aligned with the rubidium clock or the satellite clock is input to the test system as the standard clock by using a phase-locked manner.

Preferably, in step S3, the pll module is implemented by using chips such as CD4046, the locked phase-locked voltage is the center voltage (generally Vcc/2), and the comparator directly determines and compares the center voltage with the locked phase-locked voltage, so as to determine whether the tested VCXO can be locked, if the locked VCXO meets the requirements (the voltage control range and the output frequency index are both normal), otherwise, the VCXO is a faulty product.

Preferably, the middle part of the movable pile driving platform is provided with a pile driving hole for the pile driving hammer to freely enter and exit.

Has the advantages that: the frequency test of the multi-channel voltage-controlled crystal oscillator can be simultaneously carried out, the test efficiency of the voltage-controlled crystal oscillator can be improved, the test cost is reduced, and the test efficiency is improved.

Of course, it is not necessary for any one product that embodies the invention to achieve all of the above advantages simultaneously.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a frequency testing scheme of a multi-channel voltage-controlled crystal oscillator according to the present invention;

FIG. 2 is a schematic diagram of an exemplary voltage controlled crystal oscillator test according to the present invention;

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in FIG. 1-2, the present invention is a VCG frequency test system, which comprises a test board body, wherein the test board body is respectively provided with a VCG frequency to be tested and a mark frequency source, the VCG frequency to be tested and the mark frequency source are phase-locked by a phase-locked loop,

the phase-locked loop outputs a voltage-controlled crystal oscillator which meets the requirement of the required frequency and the voltage-controlled range, the phase-locked loop can be normally locked, otherwise, the phase-locked loop cannot be locked, the voltage-controlled crystal oscillator test is completed according to the phase-locked result output by the phase-locked loop, a plurality of phase-locked loops are adopted on the test board, and the multi-path voltage-controlled crystal oscillator test is simultaneously carried out.

One specific application of this embodiment is: a voltage controlled crystal oscillator frequency test system and scheme, according to the phase-locked loop principle, to the crystal oscillator that accords with the phase-locked requirement, the normal phase-locked, input the standard frequency source, provide the standard clock through clock sources such as rubidium clock or big dipper satellite, the phase-locked loop is realized, the front end inputs the standard frequency and processes to the same frequency as tested VCXO, reduce the phase-locked loop module functional requirement, the phase-locked loop module does not need to carry on the frequency division alignment, carry on the phase discrimination comparison directly, the test result is outputted to the host computer through the test bus to record, finish the test, test to a 10MHz, the voltage controlled crystal oscillator of the voltage controlled range is + -10 ppm, a 9MHz voltage controlled crystal oscillator tests, output "1", do not accord with the phase-locked requirement or vacancy test circuit, output "0", the host computer reads the test result bus directly, obtain the test result, the first path crystal, if the tested VCXO is inconsistent with the clock source frequency, a phase-locking mode is adopted, the clock with the testing frequency aligned with the rubidium clock or the satellite clock is input into the testing system as a standard clock, the standard clock is used, a phase-locked loop module is realized by adopting chips such as CD4046 and the like, the locked phase-locked voltage is the central voltage (generally Vcc/2), a comparator is adopted to directly judge and compare, whether the tested VCXO can be locked or not can be obtained, if the tested VCXO can be locked, the tested VCXO meets the requirements (the voltage control range and the output frequency index are normal), and if not, the tested VCXO is a fault product.

In the description herein, references to the description of "one embodiment," "an example," "a specific example," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments have not been described in detail to avoid obscuring the description of the invention in its specific form, and it is to be understood that many modifications and variations are possible in light of the teaching of this specification. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A voltage-controlled crystal oscillator frequency test system is characterized in that: the test board body is provided with a voltage controlled crystal oscillator frequency to be tested and a mark frequency source respectively, and the voltage controlled crystal oscillator frequency to be tested and the mark frequency source are phase-locked through a phase-locked loop.

2. The system of claim 1, wherein: the phase-locked loop outputs the voltage-controlled crystal oscillator which meets the requirement of the required frequency and the voltage-controlled range, the phase-locked loop can be normally locked, otherwise, the phase-locked loop cannot be locked, and the voltage-controlled crystal oscillator test is completed according to the phase-locked result output by the phase-locked loop.

3. The system of claim 1, wherein: and the test board adopts a plurality of phase-locked loops and simultaneously performs multi-path voltage-controlled crystal oscillator test.

4. The voltage controlled crystal oscillator frequency test scheme of claim 1, wherein:

step S1, normally locking the phase of the crystal oscillator meeting the phase locking requirement according to the phase-locked loop principle;

step S2, inputting a standard frequency source, and providing a standard clock by a rubidium clock or Beidou satellite and other clock sources;

and step S3, realizing phase-locked loop, processing the front-end input standard frequency into the same frequency as the tested VCXO, reducing the functional requirement of the phase-locked loop module, and directly performing phase discrimination comparison without performing frequency division alignment on the phase-locked loop module.

And step S4, outputting the test result to the upper computer through the test bus to record, and completing the test.

5. The voltage controlled crystal oscillator frequency test scheme of claim 4, wherein: and S1, testing a voltage-controlled crystal oscillator with voltage control range of +/-10 ppm and a voltage-controlled crystal oscillator with voltage control range of 9MHz, outputting '1', not meeting the phase-locking requirement or the vacancy test path, outputting '0', directly reading a test result bus by an upper computer to obtain a test result, and testing the first crystal oscillator.

6. The voltage controlled crystal oscillator frequency test scheme of claim 1, wherein: in step S2, a normal clock source is provided at 10MHz, and if the tested VCXO is not consistent with the clock source frequency, a phase-locked mode is adopted, and the clock with the testing frequency aligned with the rubidium clock or the satellite clock is input into the testing system as the standard clock and used as the standard clock.

7. The voltage controlled crystal oscillator frequency test scheme of claim 1, wherein: in step S3, the phase-locked loop module is implemented by using chips such as CD4046, the locked phase-locked voltage is the center voltage (generally Vcc/2), and the comparator is used to directly judge and compare, so as to determine whether the tested VCXO can be locked, if the locked VCXO meets the requirements (the voltage control range and the output frequency index are normal), otherwise, the locked VCXO is a faulty product.