CN214750622U

CN214750622U - Clamp for verifying frequency offset performance of crystal

Info

Publication number: CN214750622U
Application number: CN202120900978.9U
Authority: CN
Inventors: 陈晨
Original assignee: Taicang T&W Electronics Co Ltd
Current assignee: Taicang T&W Electronics Co Ltd
Priority date: 2021-04-28
Filing date: 2021-04-28
Publication date: 2021-11-16
Anticipated expiration: 2031-04-28

Abstract

The utility model discloses a verify anchor clamps of crystal frequency offset performance, including the PCB board, be equipped with crystal seat, first terminal, second terminal, variable capacitance CX1 and variable capacitance CX2 on the PCB board, the crystal seat has four pins, first terminal links to each other with the pin a of crystal seat, the second terminal links to each other with the pin c of crystal seat, variable capacitance CX1 one end is connected with the pin a of crystal seat, and the other end is connected with the pin b of crystal seat, variable capacitance CX1 still ground connection with the one end that pin b is connected, variable capacitance CX2 one end is connected with the pin c of crystal seat, and the other end is connected with the pin d of crystal seat, variable capacitance CX2 still ground connection with the one end that pin d is connected. The implementation is easy, whether the external clock verification circuit normally works or not is observed by adjusting the size of the adjustable capacitor CX1 and the adjustable capacitor CX2, and the parameters of the crystal frequency deviation performance can be obtained by measuring the frequency of the clock signal through an oscilloscope.

Description

Clamp for verifying frequency offset performance of crystal

Technical Field

The utility model relates to a verify anchor clamps of crystal frequency deviation performance for the verification of crystal frequency deviation performance, mainly used research and development stage crystal frequency deviation performance's verification.

Background

In order to verify whether the crystal can normally work, the frequency offset performance needs to be verified, and since the crystal is greatly influenced by external environments such as temperature, altitude and the like, the cost for verifying the frequency offset performance of the crystal in different places is high. It is not possible to verify the crystal frequency offset performance at different locations because of the high cost of using a jig to verify despite the switching thoughts.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to above-mentioned prior art not enough, provide an anchor clamps of verifying crystal frequency offset performance, through the size of adjusting adjustable electric capacity CX1 and adjustable electric capacity CX2, go to observe whether normal work of outside clock verification circuit, at the clock signal frequency of measurationing through the oscilloscope, can obtain the parameter of crystal frequency offset performance. The scheme has low cost and convenient operation.

In order to solve the above problems, the utility model adopts the following technical proposal:

the utility model provides a verify anchor clamps of crystal frequency offset performance, includes the PCB board, be equipped with crystal seat, first terminal, second terminal, variable capacitance CX1 and variable capacitance CX2 on the PCB board, the crystal seat has four pins, first terminal links to each other with the pin a of crystal seat, the second terminal links to each other with the pin c of crystal seat, variable capacitance CX1 one end is connected with the pin a of crystal seat, and the other end is connected with the pin b of crystal seat, the one end that variable capacitance CX1 and pin b are connected still ground, variable capacitance CX2 one end is connected with the pin c of crystal seat, and the other end is connected with the pin d of crystal seat, the one end that variable capacitance CX2 and pin d are connected still ground.

The further technical scheme is that the crystal base is a 4-pin SMT patch.

The further technical scheme is that the first terminal and the second terminal are SMA female head seats.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: the implementation is easy, whether the external clock verification circuit normally works or not is observed by adjusting the size of the adjustable capacitor CX1 and the adjustable capacitor CX2, and the parameters of the crystal frequency deviation performance can be obtained by measuring the frequency of the clock signal through an oscilloscope. The clamp is simple to manufacture, does not need to buy a high-price instrument independently, has low cost and has high cost performance.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

In the figure: 1. a PCB board; 2. a crystal mount; 3. a first terminal; 4. a second terminal.

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings and examples. The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

As shown in fig. 1, a verify anchor clamps of crystal frequency offset performance for the verification of crystal frequency offset performance, including PCB board 1, be equipped with crystal holder 2, first terminal 3, second terminal 4, variable capacitance CX1 and variable capacitance CX2 on the PCB board 1, crystal holder 2 has four pins, first terminal 3 links to each other with crystal holder 2's pin a, second terminal 4 links to each other with crystal holder 2's pin c, variable capacitance CX1 one end is connected with crystal holder 2's pin a, and the other end is connected with crystal holder 2's pin b, variable capacitance CX1 still grounds with the one end that pin b is connected, variable capacitance CX2 one end is connected with crystal holder 2's pin c, and the other end is connected with crystal holder 2's pin d, the one end that variable capacitance CX2 and pin d are connected still grounds.

Wherein, crystal seat 2 is 4 foot SMT paster. The first terminal 3 and the second terminal 4 are SMA female head seats.

When the clamp is used for verification, the clock verification circuit is connected with the first terminal 3 and the second terminal 4 of the clamp through the SMA cable, and then a 25MHz crystal to be verified is welded on the crystal seat, wherein the nominal frequency of the crystal is 25 MHz. Firstly, the capacitance of the variable capacitor CX1 and the capacitance of the variable capacitor CX2 are adjusted to be 18pf, an oscilloscope is used for testing the frequency of a clock signal at a pin a of the crystal base 2, the frequency at the moment is recorded to be 25.001MHz, and the external clock verification circuit can work normally by checking, which shows that the crystal can work normally under the condition that the frequency offset is 0.001MHz without influence. And then adjusting the capacitance of the variable capacitor CX1 and the capacitance of the variable capacitor CX2 to be 28pf, testing the frequency of the clock signal at the pin a of the crystal base 2 through an oscilloscope, recording the frequency at the moment to be 25.005MHz, checking that the external clock verification circuit can still normally work, and showing that the external clock verification circuit can normally work under the condition that the frequency offset of the crystal is 0.005MHz without influence. And finally, adjusting the capacitance of the variable capacitor CX1 and the capacitance of the variable capacitor CX2 to be 38pf, testing the frequency of a clock signal at a pin a of the crystal base 2 by using an oscilloscope, recording the frequency at the moment to be 25.01MHz, checking that an external clock verification circuit cannot normally work, and recording the parameter when the frequency offset of the crystal is 0.01MHz and the external clock verification circuit cannot normally work.

The principle is as follows: 1. the utility model discloses an anchor clamps are used for exporting the clock signal that the crystal generated to outside clock verification circuit, form feedback loop by a pin and b pin, verify whether the circuit can normally work through the outside clock and can verify the power of crystal frequency deviation performance. 2. The crystal seat 2 is a 4-pin SMT paster, a 25MHz crystal to be verified is directly welded on the crystal seat, and a pin is a CLOCK OUT pin of the crystal. The pin b and the pin d are crystal grounding pins. The pin c is a CLOCK IN pin, and the variable capacitor CX1 and the variable capacitor CX2 are adjustable capacitors for adjusting the frequency deviation of the crystal, namely adjusting the frequency deviation performance of the crystal.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the embodiments of the present invention.

Claims

1. The utility model provides a verify anchor clamps of crystal frequency deviation performance which characterized in that: including PCB board (1), be equipped with crystal seat (2), first terminal (3), second terminal (4), variable capacitance CX1 and variable capacitance CX2 on PCB board (1), crystal seat (2) have four pins, first terminal (3) link to each other with the pin a of crystal seat (2), second terminal (4) link to each other with the pin c of crystal seat (2), variable capacitance CX1 one end is connected with the pin a of crystal seat (2), and the other end is connected with the pin b of crystal seat (2), the one end that variable capacitance CX1 and pin b are connected still ground connection, variable capacitance CX2 one end is connected with the pin c of crystal seat (2), and the other end is connected with the pin d of crystal seat (2), the one end that variable capacitance CX2 and pin d are connected still ground connection.

2. The apparatus of claim 1, wherein the apparatus further comprises: the crystal base (2) is a 4-pin SMT paster.

3. The apparatus of claim 1, wherein the apparatus further comprises: the first terminal (3) and the second terminal (4) are SMA female head seats.