Constant temperature crystal oscillator phase noise test system

Abstract

The invention discloses an oven controlled crystal oscillator phase noise testing system, and belongs to the field of oven controlled crystal oscillator testing. The system comprises a standard source, a phase noise tester, a channel selection unit, a power-up control unit, a signal transmission unit, a control unit, a computer and a direct-current stabilized power supply. According to the invention, batch automatic testing of the phase noise index of the oven controlled crystal oscillator can be realized.

Description

Technical Field

[0001] The invention relates to the field of constant temperature crystal oscillator testing, and in particular to a large-scale constant temperature crystal oscillator phase noise testing system. Background Art

[0002] The oven-controlled crystal oscillator is a high-performance crystal oscillator. It uses the constant temperature bath technology to keep the temperature of the quartz crystal resonator constant, thereby greatly reducing the oscillator output frequency changes caused by ambient temperature changes, providing extremely high frequency stability and accuracy. It is mainly used in communications, navigation, test and measurement equipment and other fields to provide a time reference. The phase noise index of the oven-controlled crystal oscillator is a very important parameter and one of the key factors affecting communication quality. It needs to be tested during the production process to meet customer needs. The current testing method can only be performed manually on a single unit, and cannot be automatically tested in batches. Summary of the invention

[0003] In order to realize batch production, the present invention proposes a constant temperature crystal oscillator phase noise testing system, which can realize batch automatic testing of the constant temperature crystal oscillator phase noise index.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: A constant temperature crystal oscillator phase noise test system, comprising: a standard source, a phase noise tester, a channel selection unit, a power-on control unit, a signal transmission unit, a control unit, a computer and a DC regulated power supply; The standard source is an ultra-low phase noise frequency module, which is connected to a phase noise tester to provide a reference signal for it; the phase noise tester is connected to a computer and generates a phase noise image or data file through the computer; The channel selection unit includes at least one shift register and a decoder; the address end of the decoder is connected to the control unit, and the output end is connected to the enable end of the shift register; the control end of the shift register is connected to the control unit, and the output end is respectively connected to the signal transmission unit and the power-on control unit; the channel selection unit can be expanded by parallel connection; The power-on control unit includes at least one controllable switch, the output of the channel selection unit register is connected to the control end of the controllable switch, and the DC voltage-regulated power supply is connected to the constant-temperature crystal oscillator through the controllable switch, so that the channel selection unit can independently control the power on and off of a single constant-temperature crystal oscillator; The signal transmission unit includes at least one cooperative control unit and a high-frequency signal switch, one input end of the cooperative control unit is connected to the output end of the shift register of the channel selection unit, the other input ends of all the cooperative control units are connected in parallel to the control unit, and the output end of the cooperative control unit is connected to the control end of the high-frequency signal switch; the normally open end a of each high-frequency signal switch is connected to the constant temperature crystal oscillator, the normally closed end a is suspended, and the common end a is connected to the normally open end b; the normally closed end b of the first high-frequency signal switch is suspended, and the common end b is connected to the normally closed end b of the next high-frequency signal switch; the common end b of the last high-frequency signal switch is connected to the phase noise tester; the signal transmission unit can be expanded by parallel connection; The control unit includes at least one MCU, which is connected to a computer, receives control instructions from the control software in the computer, controls the channel selection unit, the signal transmission unit, and the power-on control unit, powers on and preheats the oven-controlled crystal oscillator, and conducts the frequency signal of the tested channel to the phase noise tester; The computer runs the phase noise tester test software and the test system control software, and is connected to the phase noise tester, the control unit and the DC regulated power supply. The test system control software controls the DC regulated power supply to adjust the voltage, sends control instructions to the control unit, conducts the corresponding constant temperature crystal oscillator frequency signal to the phase noise tester, and controls the phase noise tester test software to store phase noise images or data.

[0005] Compared with the background technology, the present invention has the following beneficial effects: The testing device of the present invention can complete batch automatic testing of the phase noise index of the constant temperature crystal oscillator, automatically store the test images or data, realize data traceability, improve work efficiency, and increase production capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 This is a general block diagram of a temperature-controlled crystal oscillator phase noise test system in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of a channel selection unit in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of a power-on control unit in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of a signal transmission unit in Embodiment 1 of the present invention; Figure 5 This is a general block diagram of a temperature-controlled crystal oscillator phase noise test system in Embodiment 2 of the present invention; Figure 6 This is a functional schematic diagram of a primary control panel in Embodiment 2 of the present invention; Figure 7 This is a functional schematic diagram of the secondary control panel in the second embodiment of the present invention; Figure 8This is a functional schematic diagram of the test board in the second embodiment of the present invention. DETAILED DESCRIPTION

[0007] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0008] The present invention is further described below in conjunction with embodiments, the purpose of which is only to better understand the content of the present invention. Therefore, the specific embodiments cited do not limit the protection scope of the present invention, and the accompanying drawings only show parts related to the present invention rather than all structures.

[0009] Embodiment 1:

[0010] See also Figure 1 , a constant temperature crystal oscillator phase noise test system, including: a standard source, a phase noise tester, a channel selection unit, a power-on control unit, a signal transmission unit, a control unit, a computer, and a DC regulated power supply; See also Figure 2 ,The channel selection unit includes a decoder and a plurality of shift registers; See also Figure 3 , the power-on control unit includes a plurality of controllable switches; See also Figure 4 , the signal transmission unit includes a plurality of cooperative control units and a plurality of high-frequency relays; This embodiment includes: a standard source, a phase noise tester, a channel selection unit, a power-on control unit, a signal transmission unit, a control unit, a computer, and a DC regulated power supply; Among them, the standard source is an ultra-low phase noise frequency module, which is connected to the phase noise tester to provide it with a reference signal; Wherein, the phase noise tester is connected to a computer, and a phase noise image or data file is generated by special software in the computer; The channel selection unit includes at least one shift register and a decoder, the address end of the decoder is connected to the control unit, the output end is connected to the enable end of the shift register, the control end of the shift register is connected to the control unit, the output end is connected to the signal transmission unit and the power-on control unit, and the channel selection unit can be expanded by parallel connection; The power-on control unit includes at least one controllable switch, the output of the channel selection unit register is connected to the control end of the controllable switch, and the DC voltage-regulated power supply is connected to the constant-temperature crystal oscillator through the controllable switch, so that the channel selection unit can independently control the power on and off of a single constant-temperature crystal oscillator; Wherein, the signal transmission unit includes at least one cooperative control unit and a high-frequency signal switch, one of the input ends of the cooperative control unit is connected to the output end of the shift register of the channel selection unit, the other input ends of all the cooperative control units are connected in parallel and then connected to the control unit, the output end of the cooperative control unit is connected to the control end of the high-frequency signal switch, the normally open end a of each high-frequency signal switch is connected to the frequency output end of the constant temperature crystal oscillator, the normally closed end a is suspended, the common end a is connected to the normally open end b, the normally closed end b of the first high-frequency signal switch is suspended, the common end b is connected to the normally closed end b of the next high-frequency signal switch, and the common end b of the last high-frequency signal switch is connected to the phase noise tester, so that the channel selection unit and the control unit can cooperate to control the high-frequency signal switch, select the frequency signal of the constant temperature crystal oscillator of a certain channel and transmit it to the phase noise tester, and the signal transmission unit can be expanded by parallel connection; The control unit includes at least one MCU, which is connected to a computer, receives control instructions from the control software in the computer, controls the channel selection unit, the signal transmission unit, and the power-on control unit, powers on and preheats the constant temperature crystal oscillator, and conducts the frequency signal of the tested channel to the phase noise tester; The computer includes phase noise tester test software and test system control software, which are connected to the phase noise tester, the control unit and the DC regulated power supply. The test system control software controls the DC regulated power supply to adjust the voltage, sends control instructions to the control unit, conducts the corresponding constant temperature crystal oscillator frequency signal to the phase noise tester, and controls the phase noise tester test software to store phase noise images or data; The operator loads the constant temperature crystal oscillator on the test system, opens the test software in the computer, selects the screenshot path, presses the unit to load the constant temperature crystal oscillator to check the test channel, selects the new file, selects the file storage path, sets the file name and creates a new data storage table, clicks to start the test, and the test software sends a test channel instruction to the control unit according to the checked test channel. The control unit controls the channel selection unit and the power-on control unit to pre-power on the constant temperature crystal oscillator of the selected channel, and controls the signal transmission unit to transmit the channel frequency signal to the phase noise tester. The test software controls the keyboard to operate the phase noise tester software to perform phase noise testing. After the test is completed, a screenshot is taken to save the test image. The test software turns on the selected channels in turn and stores the phase noise image of the constant temperature crystal oscillator of the corresponding channel until all checked channel tests are completed and the test is terminated. The operator determines whether the test image is qualified and selects qualified products.

[0011] Embodiment 2:

[0012] See also Figure 5The constant temperature crystal oscillator test system of the present invention comprises: a test frame, a primary control board, a secondary control board, a test board, a computer, a phase noise tester, a standard source, and a DC regulated power supply. A primary control board and multiple secondary control boards are installed on the test frame, and multiple test boards are placed. The test board is connected to the multi-pin transmission interface socket of the primary control board or the secondary control board through a multi-pin transmission interface plug, the primary control board is connected to the phase noise tester through a coaxial line, multiple secondary control boards are connected through a serial line and a coaxial line, and the computer is connected through a serial line. The DC regulated power supply is connected to the standard source, the primary control board, and multiple secondary control boards through a power line, the standard source is connected to the phase noise tester through a coaxial line, and the computer is connected to the phase noise tester through a USB line.

[0013] See also Figure 6 ,The first level control board includes a control single-chip computer, a frequency signal transmission unit, a serial ,communication unit, and a multi-pin transmission interface socket. The frequency signal transmission unit of the ,first level control board is connected to the phase noise tester through a ,coaxial line, and the serial communication unit of the first level control board is connected to the ,computer test board through a serial line; See also Figure 7 The secondary control board includes a control single chip microcomputer, a frequency signal transmission unit, a serial communication unit, and a multi-pin transmission interface socket. The frequency signal transmission unit of the secondary control board is connected to the frequency signal transmission unit of the primary control board through a coaxial line, and the serial communication unit of the secondary control board is connected to the serial communication unit of the primary control board through a serial line. See also Figure 8 ,The test board includes a constant-temperature crystal oscillator loading unit, a frequency signal transmission unit, a power-on control unit, a channel selection unit, and a multi-pin transmission interface plug; After the operator loads the constant temperature crystal oscillator on the test board, the operator places the test board on the test stand slide, slides it inward, and inserts the multi-pin transmission interface plug of the test board into the multi-pin transmission interface socket of the primary control board or the secondary control board. The test software in the computer is opened, the screenshot path is selected, and the test channel is checked according to the unit for loading the constant temperature crystal oscillator. The new file is selected, the file storage path is selected, and a new data storage table is created after setting the file name. The test is started. The computer sends the test channel command to the serial communication unit of the primary control board through the serial line according to the test channel checked in the software. The serial communication unit converts the level and sends the command to the primary control board. The control board single-chip microcomputer and the secondary control board single-chip microcomputer, the primary control board single-chip microcomputer and the secondary control board single-chip microcomputer determine whether it is the channel of this layer according to the instruction. If it is the test board channel corresponding to the primary control board, the primary control board single-chip microcomputer connects the multi-pin transmission interface plug of the test board through the multi-pin transmission interface socket to control the channel selection unit and the power-on control unit of the test board, pre-powers the constant temperature crystal oscillator of the selected channel, and transmits the frequency signal of the channel to the frequency signal transmission unit of the primary control board through the frequency signal transmission unit of the test board through the multi-pin transmission interface plug. The primary control board single-chip microcomputer controls the high-frequency relay of the frequency transmission unit of the primary control board to pre-power the constant temperature crystal oscillator of the selected channel through the multi-pin transmission interface socket. The frequency signal transmitted by the pin transmission interface plug is conducted to the coaxial line connected to the phase noise tester, and the frequency signal of the selected channel is transmitted to the phase noise tester. If the test unit is the test board corresponding to the secondary control board, the secondary control board single-chip microcomputer controls the channel selection unit and the power-on control unit of the test board through the multi-pin transmission interface socket to connect the multi-pin transmission interface plug of the test board, pre-powers the constant temperature crystal oscillator of the selected channel, and transmits the frequency signal of the channel to the frequency signal transmission unit of the secondary control board through the frequency signal transmission unit of the test board through the multi-pin transmission interface plug. The frequency signal transmission unit of the secondary control board is connected to the primary control board through the coaxial line. The frequency signal transmission unit of the primary control board single chip controls the high-frequency relay of the frequency transmission unit of the primary control board, and conducts the frequency signal transmitted from the coaxial line to the coaxial line connected to the phase noise tester, and transmits the frequency signal of the selected channel to the phase noise tester. The test software controls the keyboard to operate the phase noise tester software to perform phase noise test, and takes a screenshot after the test is completed to save the test image. The test software conducts the selected channels in turn and stores the phase noise image of the constant temperature crystal oscillator of the corresponding channel until the test of all checked channels is completed and the test is terminated. The operator makes image judgment through the selection software and selects qualified products according to the qualified product selection data.

Claims

1. A constant temperature crystal oscillator phase noise test system, characterized in that: include: Standard source, phase noise tester, channel selection unit, power-on control unit, signal transmission unit, control unit, computer and DC regulated power supply; The standard source is an ultra-low phase noise frequency module, which is connected to a phase noise tester to provide a reference signal for it; the phase noise tester is connected to a computer and generates a phase noise image or data file through the computer; The channel selection unit includes at least one shift register and a decoder; the address end of the decoder is connected to the control unit, and the output end is connected to the enable end of the shift register; the control end of the shift register is connected to the control unit, and the output end is respectively connected to the signal transmission unit and the power-on control unit; the channel selection unit can be expanded by parallel connection; The power-on control unit includes at least one controllable switch, the output of the channel selection unit register is connected to the control end of the controllable switch, and the DC voltage-regulated power supply is connected to the constant-temperature crystal oscillator through the controllable switch, so that the channel selection unit can independently control the power on and off of a single constant-temperature crystal oscillator; The signal transmission unit includes at least one cooperative control unit and a high-frequency signal switch, one input end of the cooperative control unit is connected to the output end of the shift register of the channel selection unit, the other input ends of all the cooperative control units are connected in parallel to the control unit, and the output end of the cooperative control unit is connected to the control end of the high-frequency signal switch; the normally open end a of each high-frequency signal switch is connected to the constant temperature crystal oscillator, the normally closed end a is suspended, and the common end a is connected to the normally open end b; the normally closed end b of the first high-frequency signal switch is suspended, and the common end b is connected to the normally closed end b of the next high-frequency signal switch; the common end b of the last high-frequency signal switch is connected to the phase noise tester; the signal transmission unit can be expanded by parallel connection; The control unit includes at least one MCU, which is connected to a computer, receives control instructions from the control software in the computer, controls the channel selection unit, the signal transmission unit, and the power-on control unit, powers on and preheats the oven-controlled crystal oscillator, and conducts the frequency signal of the tested channel to the phase noise tester; The computer runs the phase noise tester test software and the test system control software, and is connected to the phase noise tester, the control unit and the DC regulated power supply. The test system control software controls the DC regulated power supply to adjust the voltage, sends control instructions to the control unit, conducts the corresponding constant temperature crystal oscillator frequency signal to the phase noise tester, and controls the phase noise tester test software to store phase noise images or data.

Images