Ultra-low noise 10M constant temperature crystal oscillator

Abstract

The invention relates to the technical field of crystal oscillators, in particular to an ultra-low noise 10M constant temperature crystal oscillator which comprises a base, a shell, a PCB and a circuit module, the shell is connected with the base, the PCB is arranged on the base, the PCB comprises a PCB 1 and a PCB 2, and the PCB 2 is arranged on the base. The circuit module comprises a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R13, a resistor R30, a capacitor C1, a capacitor C25, a capacitor C26, a VCO, a high-stability reference source voltage stabilization module, an oscillating circuit module, a field-effect tube amplification module and a thermostatic bath heating module, the high-stability reference source voltage stabilization module, the oscillating circuit module and the field-effect tube amplification module are all arranged on the PCB 1, the thermostatic bath heating module is arranged on the PCB 2, and the capacitor C1, the capacitor C25, the capacitor C26, the VCO, the high-stability reference source voltage stabilization module, the oscillating circuit module and the field-effect tube amplification module are all arranged on the PCB 2. According to the method, the technical problem that the phase noise of a crystal oscillator used in the prior art is difficult to reach-120dBc / Hz or lower at the 1Hz offset frequency can be effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of crystal oscillators, and in particular to an ultra-low noise 10M constant temperature crystal oscillator. Background Art

[0002] With the continuous development of electronic technology, the performance level of electronic components is constantly improving. As an important reference source, crystal oscillators have strict requirements for their high stability (low phase noise, high stability, and high reliability), among which the phase noise index is very important.

[0003] The crystal oscillator used in the prior art has the problem of difficulty in achieving a phase noise of -120 dBc / Hz or lower at a 1 Hz offset frequency. Summary of the invention

[0004] The purpose of the present invention is to provide an ultra-low noise 10M constant temperature crystal oscillator, aiming to solve the technical problem that the crystal oscillator used in the prior art is difficult to achieve a phase noise of -120dBc / Hz or lower at a 1Hz offset frequency.

[0005] To achieve the above-mentioned purpose, the present invention adopts an ultra-low noise 10M constant temperature crystal oscillator, comprising a base, a housing, a PCB board and a circuit module, wherein the housing is connected to the base, the PCB board is arranged on the base, the PCB board comprises PCB1 and PCB2, the circuit module comprises resistor R1, resistor R2, resistor R3, resistor R4, resistor R13, resistor R30, capacitor C1, capacitor C25, capacitor C26, VCO, a high-stability reference source voltage stabilizing module, an oscillation circuit module, a field effect tube amplifying module and a constant temperature bath heating module, the high-stability reference source voltage stabilizing module, the oscillation circuit module and the field effect tube amplifying module are all arranged on the PCB1, and the constant temperature bath heating module is arranged on the PCB2;

[0006] The resistor R1 and the resistor R13 are both connected to the VCO, the resistor R2 and the field effect tube amplifier module are both connected to the high-stable reference source voltage stabilizing module, the resistor R3 and the capacitor C1 are both connected to the resistor R2, the capacitor C1 is grounded, the oscillation circuit module and the resistor R4 are both connected to the resistor R3, the resistor R4 is grounded, the resistor R1 is connected to the resistor R3, the resistor R4 and the oscillation circuit module, the capacitor C25 is connected to the field effect tube amplifier module, the resistor R30 and the capacitor C26 are both connected to the capacitor C25, the capacitor C26 is grounded, and the resistor R30 is connected to the high-stable reference source voltage stabilizing module.

[0007] Wherein, the high-stability reference source voltage stabilizing module includes VDC, diode D2, VCC1, capacitor C24, capacitor C28, capacitor C30, capacitor C31, capacitor C32, capacitor C33, capacitor C36, capacitor C37, chip IC1, capacitor C38, VRF1, resistor R27, resistor R28, resistor R29, resistor R31, capacitor C22, capacitor C23, capacitor C27, capacitor C29, capacitor C34, capacitor C35, capacitor C39, chip U2, transistor Q6, NC1, NC2, VCC2;

[0008] The diode D2 is connected to the VDC, the VCC1 is connected to the diode D2, the capacitor C30, the capacitor C32, the capacitor C33, the capacitor C36 and the capacitor C37 are all connected to the VCC1, and the capacitor C30, the capacitor C32, the capacitor C33, the capacitor C36 and the capacitor C37 are all grounded, the interface 2 of the chip IC1 is connected to the VCC1, the interface 3 of the chip IC1 is connected to the capacitor C38, the interface 4 of the chip IC1 is connected to the field effect tube amplifier module, the capacitor C24, the capacitor C28 and the capacitor C31 are all connected to the interface 6 of the chip IC1, and the capacitor C24, the capacitor C28 and the capacitor C31 are all connected to the power supply, and the capacitor C24, the capacitor C28 and the capacitor C31 are all connected to the field effect tube amplifier module;

[0009] The resistor R27 is connected to the VRF1, the capacitor C22, the capacitor C23, the NC1 and the capacitor C27 are all connected to the resistor R27, and the capacitor C22, the capacitor C23, the NC1 and the capacitor C27 are all grounded, the capacitor C29 is connected to the capacitor C22, the capacitor C23, the NC1 and the capacitor C27, the resistor R29 is connected to the capacitor C29 and the resistor R28, the resistor R29 is grounded, the transistor Q6 is connected to the resistor R28, the VCC2 is connected to the transistor The transistor Q6 is connected, the NC2, the capacitor C34 and the interface 1 of the chip U2 are all connected to the transistor Q6, the NC2 is grounded, the interface 4 of the chip U2 is connected to the capacitor C34, the capacitor C29, the resistor R28 and the resistor R29, the interface 2 of the chip U2 is grounded, the interface 3 of the chip U2 is connected to the capacitor C35, the resistor R31 and the capacitor C39, and the capacitor C35 and the capacitor C39 are both grounded, the resistor R31 is connected to the power supply, and the interface 5 of the chip U2 is connected to the VCC2.

[0010] Wherein, the field effect tube amplification module includes inductor L2, inductor L3, inductor L4, inductor L5, inductor L6, inductor L7, capacitor C18, capacitor C19, capacitor C20, capacitor C21, resistor R20, resistor R21, resistor R22, resistor R23, resistor R24, resistor R25, transistor Q2, transistor Q3, transistor Q4 and transistor Q5;

[0011] The inductor L2, the inductor L5 and the capacitor C18 are all connected to the high-stability reference source voltage stabilizing module, the inductor L6 is connected to the inductor L5 and the high-stability reference source voltage stabilizing module, the resistor R23 is connected to the inductor L6, the capacitor C21 and the resistor R24 ​​are both connected to the resistor R23, the capacitor C21 is grounded, the transistor Q5 and the transistor Q4 are both connected to the resistor R24, the resistor R26 is connected to the transistor Q5 and the transistor Q4, the capacitor C20 and the inductor L3 are both connected to the inductor L2, the resistor R20 is connected to the inductor L3, the resistor R 21 are connected to the capacitor C18 and the resistor R20, the capacitor C19 is connected to the capacitor C18, the capacitor C19 is grounded, the transistor Q2 and the transistor Q3 are connected to the resistor R21, the inductor L4 is connected to the transistor Q2 and the transistor Q3, the inductor L7 is connected to the capacitor C20, the transistor Q5 and the transistor Q4, the resistor R22 and the resistor R25 are connected to the inductor L4 and the inductor L7 respectively, and the resistor R22, the resistor R25, the resistor R26, the transistor Q2 and the transistor Q3 are all connected to the oscillation circuit module.

[0012] Wherein, the oscillation circuit module includes resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, resistor R11, resistor R12, resistor R13, resistor R14, resistor R15, resistor R16, resistor R17, resistor R18, resistor R19, capacitor C2, capacitor C3, capacitor C4, capacitor C5, capacitor C6, capacitor C7, capacitor C8, capacitor C9, capacitor C10, capacitor C11, capacitor C12, capacitor C13, capacitor C14, capacitor C15, capacitor C16, capacitor C17, diode D1, transistor Q2, CX1, crystal XT1 and inductor L1;

[0013] The resistor R5 is connected to the resistor R1, the resistor R9, the crystal XT1, the diode D1 and the CX1 are all connected to the resistor R5, the resistor R6 is all connected to the diode D1 and the CX1, the capacitor C3, the capacitor C4 and the resistor R7 are all connected to the resistor R6, the capacitor C5 is all connected to the capacitor C3 and the capacitor C4, the capacitor C5 is connected to the field effect tube amplifier module, the resistor R8 and the capacitor C2 are all connected to the resistor R7, the resistor R8 and the capacitor C2 are all grounded, the capacitor C8 is all connected to the resistor R9 and the crystal XT1, the capacitor C7 is connected to the capacitor C8, the capacitor C6, the capacitor C9, the capacitor C10 and the capacitor C11 are all connected to the capacitor C7, the inductor L1, the resistor R11 and the capacitor C12 are all connected to the capacitor C9, and the inductor L1, the resistor R11 and the capacitor C12 are all connected to the inductor The resistor R11 and the capacitor C12 are both connected to ground, the resistor R19 is connected to the inductor L1 and the capacitor C13, the resistor R19 is also connected to the field effect tube amplification module, the resistor R18 is connected to the capacitor C11 and the transistor Q1, the resistor R10 and the resistor R12 are both connected to the resistor R11, the resistor R12 is connected to the transistor Q1, the capacitor C17 and the resistor R17 are both connected to the transistor Q 1 is connected, the capacitor C18 is connected to the resistor R17 and is grounded, the capacitor C17 is grounded, the resistor R16 is connected to the resistor R10, the resistor R17 and a power supply, the resistor R15 is connected to the transistor Q1, the capacitor C14 is connected to the resistor R15 and is grounded, the resistor R14 is connected to the resistor R15, the capacitor C15 is connected to the resistor 14 and the resistor R13 and is grounded, and the resistor R13 is connected to the VCO.

[0014] Wherein, the constant temperature bath heating module includes VREF2, resistor R32, resistor R33, resistor R34, resistor R35, resistor R36, resistor R37, resistor R38, resistor R39, resistor R40, resistor R41, resistor R42, resistor R43, resistor R44, resistor R45, resistor R46, resistor R47, resistor R48, resistor R49, capacitor C40, capacitor C41, capacitor C42, capacitor C43, operational amplifier IC3, transistor Q7, transistor Q8, transistor Q9, transistor Q10, transistor Q11, transistor Q12, thermistor TM1, thermistor TM2, thermistor TM3, thermistor TM4 and thermistor TM5;

[0015] The resistor R32, the resistor R36 and the resistor R37 are all connected to a power supply, the resistor R38 and the resistor R33 are all connected to the resistor R32, the resistor R34 and the resistor R35 are all connected to the resistor R33 and are all grounded, the VREF2 is connected to the resistor R37, the resistor R39, the thermistor TM1, the thermistor TM2, the thermistor TM3 and the thermistor TM4 are all connected to the resistor R36, and the thermistor TM1, the thermistor TM2, the thermistor TM3 and the thermistor TM4 are all connected to the resistor R36. The resistor TM2, the thermistor TM3 and the thermistor TM4 are all grounded, the interface 3 and the interface 4 of the operational amplifier IC3 are respectively connected to the resistor R38 and the resistor R39, the interface 5 of the operational amplifier IC3 is grounded, the capacitor C41 and the capacitor C42 are both connected to the resistor R39, the capacitor C41 and the resistor R40 are both connected to the interface 1 of the operational amplifier IC3, the resistor R41 is connected to the capacitor C42, the capacitor C40 and the capacitor C43 are both connected to the The capacitor C40 is grounded, the interface 2 of the chip IC is connected to the VDC, the transistor Q7 is connected to the capacitor C43 and the resistor R40, the transistor Q7, the resistor R45, the resistor R46, the resistor R47, the resistor R48 and the resistor R49 are connected to the VCO, the resistor R43 is connected to the resistor R42 and the transistor Q7, the thermistor TM5 and the resistor R44 are connected to the resistor R43, the thermistor The resistor TM5 and the resistor R44 are both connected to the resistor R45, the transistor Q8 is both connected to the resistor R40 and the resistor R45 and is grounded, the transistor Q9 is both connected to the resistor R40 and the resistor R46 and is grounded, the transistor Q10 is both connected to the resistor R40 and the resistor R47 and is grounded, the transistor Q11 is both connected to the resistor R40 and the resistor R48 and is grounded, and the transistor Q12 is both connected to the resistor R40 and the resistor R48 and is grounded.

[0016] The ultra-low noise 10M constant temperature crystal oscillator of the present invention is provided by placing the high-stability reference source voltage stabilizing module, the test oscillation circuit module and the field effect tube amplification module on the PCB1; the crystal is mounted on the PCB1 and is located on the reverse side of the PCB, the constant temperature bath module is placed on the PCB2 and is located on the reverse side of the PCB, the heating temperature is set at 93°C, the hot air flows upward, and the cycle is repeated to keep the entire space constant at 93°C;

[0017] The high-stability reference source voltage stabilization module uses ultra-low noise, wide-range voltage stabilization chips, in conjunction with filter capacitors and power amplifier chips. After stabilizing the input voltage, it is divided into two paths and output to the oscillation circuit and the amplifier circuit respectively. The crystal generates a signal due to the piezoelectric effect after power is turned on, and oscillates through the frequency selection network and the transistor to generate a stable signal. The amplifier circuit then uses a field effect transistor to amplify the signal so that the output power meets the design requirements. After the temperature control circuit is powered on, the current limiting module limits the startup current to a reasonable range. The thermostat senses the temperature change through the thermistor TM1. As the temperature rises, the resistance value decreases, the operational amplifier outputs a high level, and the heating module stops working. As the temperature decreases, the resistance value increases, the operational amplifier outputs a low level, the heating module starts working, and eventually the thermostat reaches the set temperature;

[0018] The high-stability reference source voltage stabilization module of the PCB1 adopts a high-stability reference source chip and a power amplifier chip to provide two voltages to power the oscillation circuit and the amplifier circuit respectively, thereby minimizing the noise interference of the power supply.

[0019] The amplifier circuit uses field effect tubes, which have the advantages of low noise, low power consumption and large dynamic range, making the amplified signal cleaner and the phase noise level of the final product better.

[0020] The oscillation circuit uses triode oscillation mode, selects 10M crystal in TO8 package, and uses LC frequency selection network. The final output 10M signal has the advantages of low noise, low power consumption and high reliability.

[0021] The temperature control circuit of PCB2 uses a current limiting chip to control the startup current, senses the temperature through the thermistor, changes the resistance value, breaks the balance of the bridge circuit, and uses the operational amplifier to output high and low levels to control the output of the heating module to reach the preset temperature.

[0022] The present invention mostly uses integrated devices, which does not affect performance while reducing space. A chip mounter can be used for direct chip mounting, without manual mounting and welding, which simplifies the processing technology. The phase noise level of the product at 1HZ can reach -120dBc / Hz, which greatly improves the product performance; this method can effectively solve the technical problem that the crystal oscillator used in the prior art is difficult to achieve a phase noise of -120dBc / Hz or lower at a 1Hz offset frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 It is a structural schematic diagram of the ultra-low noise 10M constant temperature crystal oscillator of the present invention.

[0025] Figure 2 It is a circuit principle diagram of PCB1 of the present invention.

[0026] Figure 3 It is a circuit schematic diagram of PCB2 of the present invention.

[0027] 1-base, 2-housing, 3-PCB board. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0029] See also Figure 1 to Figure 3 ,in Figure 1 It is a structural schematic diagram of the ultra-low noise 10M constant temperature crystal oscillator of the present invention, Figure 2 is a circuit schematic diagram of PCB1 of the present invention, Figure 3 It is a circuit principle diagram of PCB2 of the present invention.

[0030] The present invention provides an ultra-low noise 10M constant temperature crystal oscillator, comprising a base 1, a shell 2, a PCB board 3 and a circuit module, wherein the shell 2 is connected to the base 1, the PCB board 3 is arranged on the base 1, the PCB board 3 comprises PCB1 and PCB2, the circuit module comprises a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R13, a resistor R30, a capacitor C1, a capacitor C25, a capacitor C26, a VCO, a high-stability reference source voltage stabilizing module, an oscillation circuit module, a field effect tube amplifying module and a constant temperature bath heating module, wherein the high-stability reference source voltage stabilizing module, the oscillation circuit module and the field effect tube amplifying module are all arranged on the PCB1, and the constant temperature bath heating module is arranged on the PCB2;

[0031] The resistor R1 and the resistor R13 are both connected to the VCO, the resistor R2 and the field effect tube amplifier module are both connected to the high-stable reference source voltage stabilizing module, the resistor R3 and the capacitor C1 are both connected to the resistor R2, the capacitor C1 is grounded, the oscillation circuit module and the resistor R4 are both connected to the resistor R3, the resistor R4 is grounded, the resistor R1 is connected to the resistor R3, the resistor R4 and the oscillation circuit module, the capacitor C25 is connected to the field effect tube amplifier module, the resistor R30 and the capacitor C26 are both connected to the capacitor C25, the capacitor C26 is grounded, and the resistor R30 is connected to the high-stable reference source voltage stabilizing module.

[0032] Wherein, the high-stability reference source voltage stabilizing module includes VDC, diode D2, VCC1, capacitor C24, capacitor C28, capacitor C30, capacitor C31, capacitor C32, capacitor C33, capacitor C36, capacitor C37, chip IC1, capacitor C38, VRF1, resistor R27, resistor R28, resistor R29, resistor R31, capacitor C22, capacitor C23, capacitor C27, capacitor C29, capacitor C34, capacitor C35, capacitor C39, chip U2, transistor Q6, NC1, NC2, VCC2;

[0033] The diode D2 is connected to the VDC, the VCC1 is connected to the diode D2, the capacitor C30, the capacitor C32, the capacitor C33, the capacitor C36 and the capacitor C37 are all connected to the VCC1, and the capacitor C30, the capacitor C32, the capacitor C33, the capacitor C36 and the capacitor C37 are all grounded, the interface 2 of the chip IC1 is connected to the VCC1, the interface 3 of the chip IC1 is connected to the capacitor C38, the interface 4 of the chip IC1 is connected to the field effect tube amplifier module, the capacitor C24, the capacitor C28 and the capacitor C31 are all connected to the interface 6 of the chip IC1, and the capacitor C24, the capacitor C28 and the capacitor C31 are all connected to the power supply, and the capacitor C24, the capacitor C28 and the capacitor C31 are all connected to the field effect tube amplifier module;

[0034] The resistor R27 is connected to the VRF1, the capacitor C22, the capacitor C23, the NC1 and the capacitor C27 are all connected to the resistor R27, and the capacitor C22, the capacitor C23, the NC1 and the capacitor C27 are all grounded, the capacitor C29 is connected to the capacitor C22, the capacitor C23, the NC1 and the capacitor C27, the resistor R29 is connected to the capacitor C29 and the resistor R28, the resistor R29 is grounded, the transistor Q6 is connected to the resistor R28, the VCC2 is connected to the transistor The transistor Q6 is connected, the NC2, the capacitor C34 and the interface 1 of the chip U2 are all connected to the transistor Q6, the NC2 is grounded, the interface 4 of the chip U2 is connected to the capacitor C34, the capacitor C29, the resistor R28 and the resistor R29, the interface 2 of the chip U2 is grounded, the interface 3 of the chip U2 is connected to the capacitor C35, the resistor R31 and the capacitor C39, and the capacitor C35 and the capacitor C39 are both grounded, the resistor R31 is connected to the power supply, and the interface 5 of the chip U2 is connected to the VCC2.

[0035] Wherein, the field effect tube amplification module includes inductor L2, inductor L3, inductor L4, inductor L5, inductor L6, inductor L7, capacitor C18, capacitor C19, capacitor C20, capacitor C21, resistor R20, resistor R21, resistor R22, resistor R23, resistor R24, resistor R25, transistor Q2, transistor Q3, transistor Q4 and transistor Q5;

[0036] The inductor L2, the inductor L5 and the capacitor C18 are all connected to the high-stability reference source voltage stabilizing module, the inductor L6 is connected to the inductor L5 and the high-stability reference source voltage stabilizing module, the resistor R23 is connected to the inductor L6, the capacitor C21 and the resistor R24 ​​are both connected to the resistor R23, the capacitor C21 is grounded, the transistor Q5 and the transistor Q4 are both connected to the resistor R24, the resistor R26 is connected to the transistor Q5 and the transistor Q4, the capacitor C20 and the inductor L3 are both connected to the inductor L2, the resistor R20 is connected to the inductor L3, the resistor R 21 are connected to the capacitor C18 and the resistor R20, the capacitor C19 is connected to the capacitor C18, the capacitor C19 is grounded, the transistor Q2 and the transistor Q3 are connected to the resistor R21, the inductor L4 is connected to the transistor Q2 and the transistor Q3, the inductor L7 is connected to the capacitor C20, the transistor Q5 and the transistor Q4, the resistor R22 and the resistor R25 are connected to the inductor L4 and the inductor L7 respectively, and the resistor R22, the resistor R25, the resistor R26, the transistor Q2 and the transistor Q3 are all connected to the oscillation circuit module.

[0037] Wherein, the oscillation circuit module includes resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, resistor R11, resistor R12, resistor R13, resistor R14, resistor R15, resistor R16, resistor R17, resistor R18, resistor R19, capacitor C2, capacitor C3, capacitor C4, capacitor C5, capacitor C6, capacitor C7, capacitor C8, capacitor C9, capacitor C10, capacitor C11, capacitor C12, capacitor C13, capacitor C14, capacitor C15, capacitor C16, capacitor C17, diode D1, transistor Q2, CX1, crystal XT1 and inductor L1;

[0038] The resistor R5 is connected to the resistor R1, the resistor R9, the crystal XT1, the diode D1 and the CX1 are all connected to the resistor R5, the resistor R6 is all connected to the diode D1 and the CX1, the capacitor C3, the capacitor C4 and the resistor R7 are all connected to the resistor R6, the capacitor C5 is all connected to the capacitor C3 and the capacitor C4, the capacitor C5 is connected to the field effect tube amplifier module, the resistor R8 and the capacitor C2 are all connected to the resistor R7, the resistor R8 and the capacitor C2 are all grounded, the capacitor C8 is all connected to the resistor R9 and the crystal XT1, the capacitor C7 is connected to the capacitor C8, the capacitor C6, the capacitor C9, the capacitor C10 and the capacitor C11 are all connected to the capacitor C7, the inductor L1, the resistor R11 and the capacitor C12 are all connected to the capacitor C9, and the inductor L1, the resistor R11 and the capacitor C12 are all connected to the inductor The resistor R11 and the capacitor C12 are both connected to ground, the resistor R19 is connected to the inductor L1 and the capacitor C13, the resistor R19 is also connected to the field effect tube amplification module, the resistor R18 is connected to the capacitor C11 and the transistor Q1, the resistor R10 and the resistor R12 are both connected to the resistor R11, the resistor R12 is connected to the transistor Q1, the capacitor C17 and the resistor R17 are both connected to the transistor Q 1 is connected, the capacitor C18 is connected to the resistor R17 and is grounded, the capacitor C17 is grounded, the resistor R16 is connected to the resistor R10, the resistor R17 and a power supply, the resistor R15 is connected to the transistor Q1, the capacitor C14 is connected to the resistor R15 and is grounded, the resistor R14 is connected to the resistor R15, the capacitor C15 is connected to the resistor 14 and the resistor R13 and is grounded, and the resistor R13 is connected to the VCO.

[0039] Wherein, the constant temperature bath heating module includes VREF2, resistor R32, resistor R33, resistor R34, resistor R35, resistor R36, resistor R37, resistor R38, resistor R39, resistor R40, resistor R41, resistor R42, resistor R43, resistor R44, resistor R45, resistor R46, resistor R47, resistor R48, resistor R49, capacitor C40, capacitor C41, capacitor C42, capacitor C43, operational amplifier IC3, transistor Q7, transistor Q8, transistor Q9, transistor Q10, transistor Q11, transistor Q12, thermistor TM1, thermistor TM2, thermistor TM3, thermistor TM4 and thermistor TM5;

[0040] The resistor R32, the resistor R36 and the resistor R37 are all connected to a power supply, the resistor R38 and the resistor R33 are all connected to the resistor R32, the resistor R34 and the resistor R35 are all connected to the resistor R33 and are all grounded, the VREF2 is connected to the resistor R37, the resistor R39, the thermistor TM1, the thermistor TM2, the thermistor TM3 and the thermistor TM4 are all connected to the resistor R36, and the thermistor TM1, the thermistor TM2, the thermistor TM3 and the thermistor TM4 are all connected to the resistor R36. The resistor TM2, the thermistor TM3 and the thermistor TM4 are all grounded, the interface 3 and the interface 4 of the operational amplifier IC3 are respectively connected to the resistor R38 and the resistor R39, the interface 5 of the operational amplifier IC3 is grounded, the capacitor C41 and the capacitor C42 are both connected to the resistor R39, the capacitor C41 and the resistor R40 are both connected to the interface 1 of the operational amplifier IC3, the resistor R41 is connected to the capacitor C42, the capacitor C40 and the capacitor C43 are both connected to the The capacitor C40 is grounded, the interface 2 of the chip IC is connected to the VDC, the transistor Q7 is connected to the capacitor C43 and the resistor R40, the transistor Q7, the resistor R45, the resistor R46, the resistor R47, the resistor R48 and the resistor R49 are connected to the VCO, the resistor R43 is connected to the resistor R42 and the transistor Q7, the thermistor TM5 and the resistor R44 are connected to the resistor R43, the thermistor The resistor TM5 and the resistor R44 are both connected to the resistor R45, the transistor Q8 is both connected to the resistor R40 and the resistor R45 and is grounded, the transistor Q9 is both connected to the resistor R40 and the resistor R46 and is grounded, the transistor Q10 is both connected to the resistor R40 and the resistor R47 and is grounded, the transistor Q11 is both connected to the resistor R40 and the resistor R48 and is grounded, and the transistor Q12 is both connected to the resistor R40 and the resistor R48 and is grounded.

[0041] An ultra-low noise 10M constant temperature crystal oscillator of the present embodiment is used, by placing the high-stability reference source voltage stabilizing module, the test oscillation circuit module and the field effect tube amplification module on the PCB1; the crystal is mounted on the PCB1, located on the reverse side of the PCB, the constant temperature bath module is placed on the PCB2, located on the reverse side of the PCB, the heating temperature is set at 93°C, the hot air flow rises, and the cycle is repeated to keep the entire space constant at 93°C;

[0042] The high-stability reference source voltage stabilization module uses ultra-low noise, wide-range voltage stabilization chips, in conjunction with filter capacitors and power amplifier chips. After stabilizing the input voltage, it is divided into two paths and output to the oscillation circuit and the amplifier circuit respectively. The crystal generates a signal due to the piezoelectric effect after power is turned on, and oscillates through the frequency selection network and the transistor to generate a stable signal. The amplifier circuit then uses a field effect transistor to amplify the signal so that the output power meets the design requirements. After the temperature control circuit is powered on, the current limiting module limits the startup current to a reasonable range. The thermostat senses the temperature change through the thermistor TM1. As the temperature rises, the resistance value decreases, the operational amplifier outputs a high level, and the heating module stops working. As the temperature decreases, the resistance value increases, the operational amplifier outputs a low level, the heating module starts working, and eventually the thermostat reaches the set temperature;

[0043] The high-stability reference source voltage stabilization module of the PCB1 adopts a high-stability reference source chip and a power amplifier chip to provide two voltages to power the oscillation circuit and the amplifier circuit respectively, thereby minimizing the noise interference of the power supply.

[0044] The amplifier circuit uses field effect tubes, which have the advantages of low noise, low power consumption and large dynamic range, making the amplified signal cleaner and the phase noise level of the final product better.

[0045] The oscillation circuit uses triode oscillation mode, selects 10M crystal in TO8 package, and uses LC frequency selection network. The final output 10M signal has the advantages of low noise, low power consumption and high reliability.

[0046] The temperature control circuit of PCB2 uses a current limiting chip to control the startup current, senses the temperature through the thermistor, changes the resistance value, breaks the balance of the bridge circuit, and uses the operational amplifier to output high and low levels to control the output of the heating module to reach the preset temperature.

[0047] The present invention mostly uses integrated devices, which does not affect performance while reducing space. A chip mounter can be used for direct chip mounting, without manual mounting and welding, which simplifies the processing technology. The phase noise level of the product at 1HZ can reach -120dBc / Hz, which greatly improves the product performance; this method can effectively solve the technical problem that the crystal oscillator used in the prior art is difficult to achieve a phase noise of -120dBc / Hz or lower at a 1Hz offset frequency.

[0048] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. An ultra-low noise 10M oven-controlled crystal oscillator, characterized in that: It includes a base, a shell, a PCB board and a circuit module, wherein the shell is connected to the base, the PCB board is arranged on the base, the PCB board includes PCB1 and PCB2, the circuit module includes resistor R1, resistor R2, resistor R3, resistor R4, resistor R13, resistor R30, capacitor C1, capacitor C25, capacitor C26, VCO, a high-stability reference source voltage stabilizing module, an oscillation circuit module, a field effect tube amplifying module and a constant temperature bath heating module, the high-stability reference source voltage stabilizing module, the oscillation circuit module and the field effect tube amplifying module are all arranged on the PCB1, and the constant temperature bath heating module is arranged on the PCB2; The resistor R1 and the resistor R13 are both connected to the VCO, the resistor R2 and the field effect tube amplifier module are both connected to the high-stable reference source voltage stabilizing module, the resistor R3 and the capacitor C1 are both connected to the resistor R2, the capacitor C1 is grounded, the oscillation circuit module and the resistor R4 are both connected to the resistor R3, the resistor R4 is grounded, the resistor R1 is connected to the resistor R3, the resistor R4 and the oscillation circuit module, the capacitor C25 is connected to the field effect tube amplifier module, the resistor R30 and the capacitor C26 are both connected to the capacitor C25, the capacitor C26 is grounded, and the resistor R30 is connected to the high-stable reference source voltage stabilizing module.

2. The ultra-low noise 10M oven-controlled crystal oscillator according to claim 1, characterized in that: The high-stability reference source voltage stabilizing module includes VDC, diode D2, VCC1, capacitor C24, capacitor C28, capacitor C30, capacitor C31, capacitor C32, capacitor C33, capacitor C36, capacitor C37, chip IC1, capacitor C38, VRF1, resistor R27, resistor R28, resistor R29, resistor R31, capacitor C22, capacitor C23, capacitor C27, capacitor C29, capacitor C34, capacitor C35, capacitor C39, chip U2, transistor Q6, NC1, NC2, VCC2; The diode D2 is connected to the VDC, the VCC1 is connected to the diode D2, the capacitor C30, the capacitor C32, the capacitor C33, the capacitor C36 and the capacitor C37 are all connected to the VCC1, and the capacitor C30, the capacitor C32, the capacitor C33, the capacitor C36 and the capacitor C37 are all grounded, the interface 2 of the chip IC1 is connected to the VCC1, the interface 3 of the chip IC1 is connected to the capacitor C38, the interface 4 of the chip IC1 is connected to the field effect tube amplifier module, the capacitor C24, the capacitor C28 and the capacitor C31 are all connected to the interface 6 of the chip IC1, and the capacitor C24, the capacitor C28 and the capacitor C31 are all connected to the power supply, and the capacitor C24, the capacitor C28 and the capacitor C31 are all connected to the field effect tube amplifier module; The resistor R27 is connected to the VRF1, the capacitor C22, the capacitor C23, the NC1 and the capacitor C27 are all connected to the resistor R27, and the capacitor C22, the capacitor C23, the NC1 and the capacitor C27 are all grounded, the capacitor C29 is connected to the capacitor C22, the capacitor C23, the NC1 and the capacitor C27, the resistor R29 is connected to the capacitor C29 and the resistor R28, the resistor R29 is grounded, the transistor Q6 is connected to the resistor R28, the VCC2 is connected to the transistor The transistor Q6 is connected, the NC2, the capacitor C34 and the interface 1 of the chip U2 are all connected to the transistor Q6, the NC2 is grounded, the interface 4 of the chip U2 is connected to the capacitor C34, the capacitor C29, the resistor R28 and the resistor R29, the interface 2 of the chip U2 is grounded, the interface 3 of the chip U2 is connected to the capacitor C35, the resistor R31 and the capacitor C39, and the capacitor C35 and the capacitor C39 are both grounded, the resistor R31 is connected to the power supply, and the interface 5 of the chip U2 is connected to the VCC2.

3. The ultra-low noise 10M oven-controlled crystal oscillator according to claim 2, characterized in that: The field effect tube amplification module includes an inductor L2, an inductor L3, an inductor L4, an inductor L5, an inductor L6, an inductor L7, a capacitor C18, a capacitor C19, a capacitor C20, a capacitor C21, a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R25, a transistor Q2, a transistor Q3, a transistor Q4 and a transistor Q5; The inductor L2, the inductor L5 and the capacitor C18 are all connected to the high-stability reference source voltage stabilizing module, the inductor L6 is connected to the inductor L5 and the high-stability reference source voltage stabilizing module, the resistor R23 is connected to the inductor L6, the capacitor C21 and the resistor R24 ​​are both connected to the resistor R23, the capacitor C21 is grounded, the transistor Q5 and the transistor Q4 are both connected to the resistor R24, the resistor R26 is connected to the transistor Q5 and the transistor Q4, the capacitor C20 and the inductor L3 are both connected to the inductor L2, the resistor R20 is connected to the inductor L3, the resistor R 21 are connected to the capacitor C18 and the resistor R20, the capacitor C19 is connected to the capacitor C18, the capacitor C19 is grounded, the transistor Q2 and the transistor Q3 are connected to the resistor R21, the inductor L4 is connected to the transistor Q2 and the transistor Q3, the inductor L7 is connected to the capacitor C20, the transistor Q5 and the transistor Q4, the resistor R22 and the resistor R25 are connected to the inductor L4 and the inductor L7 respectively, and the resistor R22, the resistor R25, the resistor R26, the transistor Q2 and the transistor Q3 are all connected to the oscillation circuit module.

4. The ultra-low noise 10M oven-controlled crystal oscillator according to claim 3, characterized in that: The oscillation circuit module includes a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a capacitor C8, a capacitor C9, a capacitor C10, a capacitor C11, a capacitor C12, a capacitor C13, a capacitor C14, a capacitor C15, a capacitor C16, a capacitor C17, a diode D1, a transistor Q2, a CX1, a crystal XT1 and an inductor L1; The resistor R5 is connected to the resistor R1, the resistor R9, the crystal XT1, the diode D1 and the CX1 are all connected to the resistor R5, the resistor R6 is all connected to the diode D1 and the CX1, the capacitor C3, the capacitor C4 and the resistor R7 are all connected to the resistor R6, the capacitor C5 is all connected to the capacitor C3 and the capacitor C4, the capacitor C5 is connected to the field effect tube amplifier module, the resistor R8 and the capacitor C2 are all connected to the resistor R7, the resistor R8 and the capacitor C2 are all grounded, the capacitor C8 is all connected to the resistor R9 and the crystal XT1, the capacitor C7 is connected to the capacitor C8, the capacitor C6, the capacitor C9, the capacitor C10 and the capacitor C11 are all connected to the capacitor C7, the inductor L1, the resistor R11 and the capacitor C12 are all connected to the capacitor C9, and the inductor L1, the resistor R11 and the capacitor C12 are all connected to the inductor The resistor R11 and the capacitor C12 are both connected to ground, the resistor R19 is connected to the inductor L1 and the capacitor C13, the resistor R19 is also connected to the field effect tube amplification module, the resistor R18 is connected to the capacitor C11 and the transistor Q1, the resistor R10 and the resistor R12 are both connected to the resistor R11, the resistor R12 is connected to the transistor Q1, the capacitor C17 and the resistor R17 are both connected to the transistor Q 1 is connected, the capacitor C18 is connected to the resistor R17 and is grounded, the capacitor C17 is grounded, the resistor R16 is connected to the resistor R10, the resistor R17 and a power supply, the resistor R15 is connected to the transistor Q1, the capacitor C14 is connected to the resistor R15 and is grounded, the resistor R14 is connected to the resistor R15, the capacitor C15 is connected to the resistor 14 and the resistor R13 and is grounded, and the resistor R13 is connected to the VCO.

5. The ultra-low noise 10M oven-controlled crystal oscillator according to claim 4, characterized in that: The constant temperature bath heating module includes VREF2, resistor R32, resistor R33, resistor R34, resistor R35, resistor R36, resistor R37, resistor R38, resistor R39, resistor R40, resistor R41, resistor R42, resistor R43, resistor R44, resistor R45, resistor R46, resistor R47, resistor R48, resistor R49, capacitor C40, capacitor C41, capacitor C42, capacitor C43, operational amplifier IC3, transistor Q7, transistor Q8, transistor Q9, transistor Q10, transistor Q11, transistor Q12, thermistor TM1, thermistor TM2, thermistor TM3, thermistor TM4 and thermistor TM5; The resistor R32, the resistor R36 and the resistor R37 are all connected to a power supply, the resistor R38 and the resistor R33 are all connected to the resistor R32, the resistor R34 and the resistor R35 are all connected to the resistor R33 and are all grounded, the VREF2 is connected to the resistor R37, the resistor R39, the thermistor TM1, the thermistor TM2, the thermistor TM3 and the thermistor TM4 are all connected to the resistor R36, and the thermistor TM1, the thermistor TM2, the thermistor TM3 and the thermistor TM4 are all connected to the resistor R36. The resistor TM2, the thermistor TM3 and the thermistor TM4 are all grounded, the interface 3 and the interface 4 of the operational amplifier IC3 are respectively connected to the resistor R38 and the resistor R39, the interface 5 of the operational amplifier IC3 is grounded, the capacitor C41 and the capacitor C42 are both connected to the resistor R39, the capacitor C41 and the resistor R40 are both connected to the interface 1 of the operational amplifier IC3, the resistor R41 is connected to the capacitor C42, the capacitor C40 and the capacitor C43 are both connected to the The capacitor C40 is grounded, the interface 2 of the chip IC is connected to the VDC, the transistor Q7 is connected to the capacitor C43 and the resistor R40, the transistor Q7, the resistor R45, the resistor R46, the resistor R47, the resistor R48 and the resistor R49 are connected to the VCO, the resistor R43 is connected to the resistor R42 and the transistor Q7, the thermistor TM5 and the resistor R44 are connected to the resistor R43, the thermistor The resistor TM5 and the resistor R44 are both connected to the resistor R45, the transistor Q8 is both connected to the resistor R40 and the resistor R45 and is grounded, the transistor Q9 is both connected to the resistor R40 and the resistor R46 and is grounded, the transistor Q10 is both connected to the resistor R40 and the resistor R47 and is grounded, the transistor Q11 is both connected to the resistor R40 and the resistor R48 and is grounded, and the transistor Q12 is both connected to the resistor R40 and the resistor R48 and is grounded.

Images