CN113358908A

CN113358908A - Differential crystal oscillator test system for aviation bus

Info

Publication number: CN113358908A
Application number: CN202110626318.0A
Authority: CN
Inventors: 韩佳; 张姝瑶; 赵林; 张志远
Original assignee: Shaanxi Langcheng Zhongke Technology Development Co ltd
Current assignee: Shaanxi Langcheng Zhongke Technology Development Co ltd
Priority date: 2021-06-04
Filing date: 2021-06-04
Publication date: 2021-09-07

Abstract

The invention discloses an aviation bus differential crystal oscillator testing system, which includes a power supply and an oscilloscope, as well as a temperature box and an FPGA chip. The temperature box is provided with a crystal oscillator installation station, and the crystal oscillator installation station passes through a zero-delay buffer. It is connected to the oscilloscope in conjunction with the differential acquisition probe, the FPGA chip is electrically connected to the zero-delay buffer, the FPGA chip is electrically connected to the serial port monitoring module and the FPGA debugging interface, and the power supply is respectively connected to the multi-crystal oscillator installation station and the FPGA debugging interface. FPGA chip connection. The aviation bus differential crystal oscillator test system can effectively detect the working failure of the crystal oscillator in the low temperature or high temperature environment, screen out the defective components in time, ensure the normal communication of the aviation bus device, eliminate the defective communication boards, and reduce the maintenance cost. It is of great economic and practical significance to ensure flight safety and improve aircraft attendance.

Description

Differential crystal oscillator test system for aviation bus

Technical Field

The invention relates to the technical field of aviation bus communication, in particular to an aviation bus differential crystal oscillator test system.

Background

The aviation bus is used as an important component of an avionic system to complete communication among avionic subsystems, and has important significance in ensuring flight safety. The differential crystal oscillator is used as an important component in an aviation bus and plays an important role in normal system communication.

In recent years, the differential crystal oscillator has gradually appeared in the sight of people, and more electronic engineers prefer the differential crystal oscillator, and with the development of informatization, the differential crystal oscillator has the advantages of high performance, low power consumption and low noise, so that the differential crystal oscillator becomes a scheme with a proper design.

However, since the airplane experiences a harsh natural environment in flight, from low temperature to high temperature, quartz has a thermal hysteresis phenomenon, and thermal shock causes frequency shift, it is necessary to test the differential crystal oscillator before installation to ensure normal operation of the crystal oscillator in a severe environment.

The differential crystal oscillator generally provides a stable clock signal for the FPGA or the CPLD, and the FPGA or the CPLD is expensive, so that the stable differential crystal oscillator is necessary.

The existing testing method generally utilizes a frequency spectrograph to test the crystal oscillator, but the method is not perfect in the aspect of testing parameters such as frequency precision, frequency lifting time, duty ratio and the like of the crystal oscillator at ambient temperature, and can not efficiently and accurately check defective electrical elements, so that normal communication of the aviation bus device can not be completely guaranteed.

Therefore, the invention develops an aviation bus differential crystal oscillator test system.

Disclosure of Invention

Aiming at the defect that the prior art is not perfect in the aspects of testing parameters such as frequency precision, frequency lifting time, duty ratio and the like of a crystal oscillator at ambient temperature, the invention provides an aviation bus differential crystal oscillator testing system which can effectively detect the working faults and the like of the crystal oscillator at low-temperature or high-temperature environment, eliminate communication board cards with defects, reduce maintenance cost, ensure flight safety, improve the attendance rate of airplanes and solve the problems provided by the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

the utility model provides an aviation bus difference crystal oscillator test system, includes power and oscilloscope, still includes incubator and FPGA chip, incubator inside is provided with crystal oscillator installation station, crystal oscillator installation station passes through zero time delay buffer and difference acquisition probe cooperation and connects in oscilloscope, FPGA chip electric connection is in zero time delay buffer, FPGA chip electric connection has serial ports monitoring module and FPGA debugging interface, the power is connected with polycrystal oscillator installation station and FPGA chip respectively.

Further, the crystal oscillator installation station has 8 test slot positions in total.

Furthermore, 8 paths of differential test terminals are arranged at 8 test slot positions of the differential acquisition probe, which correspond to the crystal oscillator installation station one by one.

Further, the power supply comprises a main power supply and a secondary power supply, wherein the main power supply is preferably a DC +5V power supply, and the secondary power supply is arranged inside the incubator.

Further, the oscilloscope is used for monitoring the crystal oscillation frequency and displaying the crystal oscillation frequency in real time.

Further, the FPGA chip provides an operation code for testing the crystal oscillator.

Furthermore, the FPGA chip, the serial port monitoring module and the FPGA debugging interface are all connected to a computer host.

Further, the zero-delay buffer comprises two paths, wherein one path is connected with the FPGA chip, and the other path is connected with the coaxial cable.

Compared with the prior art, the invention has the beneficial effects that:

this aviation bus difference crystal oscillator test system, can effectively detect out the trouble problem of crystal oscillator under low temperature or high temperature environment, the frequency precision of crystal oscillator under ambient temperature has been guaranteed, the test problem of parameter such as rise and fall time and duty cycle, and then can make things convenient for the staff to select out defect components and parts are timely, avoid taking place difference crystal frequency unstability and influence its normal condition of working, can also start FPGA under high low temperature environment, and the communication test, aviation bus device's normal communication has been guaranteed, get rid of the communication integrated circuit board that has the defect, maintenance cost has been reduced, guarantee flight safety, improve the aircraft rate of attendance.

Drawings

FIG. 1 is a schematic diagram of the overall process framework of the present invention;

FIG. 2 is a cross-sectional view of the overall construction of the present invention;

in the figure: the system comprises a main power supply 1, a secondary power supply 2, a crystal oscillator mounting station 3, a zero delay buffer 4, an FPGA chip 5, a serial port monitoring module 6, an FPGA debugging interface 7, a differential acquisition probe 8, an oscilloscope 9, an incubator 10, a test slot 11, a differential test terminal 12 and a computer host 13.

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.

Referring to fig. 1-2, the present invention provides a technical solution:

the utility model provides an aviation bus difference crystal oscillator test system, including power and oscilloscope 9, still include incubator 10 and FPGA chip 5, incubator 10 is inside to be provided with crystal oscillator installation station 3, crystal oscillator installation station 3 is connected in oscilloscope 9 through zero time delay buffer 4 and the cooperation of

difference acquisition probe

8, 5 electric connection of FPGA chip in zero

time delay buffer

4, 5 electric connection of FPGA chip have serial ports monitoring module 6 and FPGA debug interface 7, the power is connected with crystal oscillator installation station 3 and FPGA chip 5 respectively.

In the invention, the crystal oscillator installation station 3 has 8 test slot positions 11. And a mounting interface is provided for crystal oscillator testing.

In the invention, 8 paths of differential test terminals 12 are arranged at 8 test slot positions 11 of the differential acquisition probes 8 corresponding to the crystal oscillator installation station 3 one by one.

In the present invention, the power supply includes a main power supply 1 and a sub power supply 2. The main power supply 1, preferably a DC +5V power supply, provides the overall power supply input to the system. The secondary power supply 2 is disposed inside the incubator 10. The secondary power supply 2 is responsible for power conversion, including power use during periods of +5V to 3.3V.

In the invention, the oscilloscope 9 is used for monitoring the crystal oscillation frequency and displaying the crystal oscillation frequency in real time.

In the invention, the FPGA chip 5 provides an operation code for the test of the crystal oscillator. And providing a crystal oscillator operation test environment and an environment for performing FC loop test.

In the invention, the FPGA chip 5, the serial port monitoring module 6 and the FPGA debugging interface 7 are all connected to a computer host 13. And the serial port monitoring module 6 is responsible for outputting a result of the system function verification. And the FPGA debugging interface 7 is responsible for upgrading and debugging the FPGA device.

In the invention, the zero-delay buffer 4 comprises two paths, wherein one path is connected with the FPGA chip 5, and the other path is connected with the coaxial cable. The advantage of coaxial cable is that it can support high bandwidth communications over relatively long unrepeatered lines, which are then connected to 8-way differential test terminals 12 via coaxial cable. The zero-delay buffer 4 is a device that fans out one clock signal into multiple clock signals with zero delay and very low skew between the outputs.

The working principle is as follows:

the test system for the differential crystal oscillator of the aviation bus comprises the following test steps:

1. firstly, installing a differential crystal oscillator in a crystal oscillator installation station 3;

2. placing the test tool into an incubator 10, and preserving heat;

3. the main power supply 1 performs power supply conversion through the secondary power supply 2 to supply power to the whole system;

4. the oscilloscope 9 acquires data through the differential acquisition probe 8 and the crystal oscillator 8-way differential test terminal 12 inside the oscilloscope;

5. then, the FPGA chip 5 provides an operation code for the crystal oscillator test and carries out a communication loop test on the operation code;

6. respectively transmitting the test information to the oscilloscope 9 and the serial port monitoring module 6;

7. the oscilloscope 9 displays the frequency in real time, and the serial port monitoring module 6 outputs the result of system function verification. The FPGA debugging interface 7 can also upgrade and debug the FPGA device.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein, and any reference signs in the claims are not intended to be construed as limiting the claim concerned.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims

1. an aviation bus differential crystal oscillator testing system, comprising a power supply and an oscilloscope, it is characterized in that: also comprise a thermostat and an FPGA chip, the interior of the thermostat is provided with a crystal oscillator installation station, and the crystal oscillator installation station passes zero time delay The buffer and the differential acquisition probe are cooperatively connected to the oscilloscope, the FPGA chip is electrically connected to the zero-delay buffer, the FPGA chip is electrically connected to the serial port monitoring module and the FPGA debugging interface, and the power supply is connected to the multi-crystal oscillator installer respectively. bit and FPGA chip connection.

2 . An aviation bus differential crystal oscillator testing system according to claim 1 , wherein the crystal oscillator installation station has a total of 8 test slots. 3 .

3 . An aviation bus differential crystal oscillator testing system according to claim 2 , wherein the differential acquisition probes are provided with 8 differential test terminals in 8 test slots corresponding to the crystal oscillator installation stations one-to-one. 4 .

4. An aviation bus differential crystal oscillator test system according to claim 1, wherein the power supply comprises a main power supply and a secondary power supply, the main power supply is preferably a DC+5V power supply, and the secondary power supply is arranged inside the incubator.

5 . An aviation bus differential crystal oscillator testing system according to claim 1 , wherein the oscilloscope is used to monitor and display the crystal frequency in real time. 6 .

6. A kind of aviation bus differential crystal oscillator testing system according to claim 1, is characterized in that: described FPGA chip provides running code for the test of crystal oscillator.

7. A kind of aviation bus differential crystal oscillator testing system according to claim 1, is characterized in that: described FPGA chip, serial port monitoring module and FPGA debugging interface are all connected to the computer host.

8 . The aviation bus differential crystal oscillator testing system according to claim 1 , wherein the zero-delay buffer comprises two paths, one of which is connected to the FPGA chip, and the other is connected to the coaxial cable. 9 .