CN201409125Y

CN201409125Y - Constant temperature phase locked crystal oscillator

Info

Publication number: CN201409125Y
Application number: CN200920057402XU
Authority: CN
Inventors: 官国阳
Original assignee: Guangzhou Shengda Electronic Co Ltd
Current assignee: Guangdong Shengda Electronic Co., Ltd.
Priority date: 2009-05-27
Filing date: 2009-05-27
Publication date: 2010-02-17
Anticipated expiration: 2019-05-27

Abstract

The utility model discloses a constant temperature phase locked crystal oscillator, which comprises a constant temperature control circuit, a standard frequency oscillatory circuit, a PLL phase lockedloop, a voltage control oscillatory output circuit and a power control circuit. The constant temperature control circuit is sequentially connected with the standard frequency oscillatory circuit, thePLL phase locked loop and the voltage control oscillatory output circuit, and the power control circuit provides stable voltage to each circuit. By utilizing novel circuit structural designs of the PLL phase locked loop with low-phase noise, the temperature constant control circuit, the standard frequency oscillatory output circuit and the like, the constant temperature phase locked crystal oscillator can keep long-term work stability at a high-frequency band and has the advantages of low phase noise and low manufacturing cost.

Description

The phase-locked crystal resonator of constant temperature

Technical field

The utility model relates to electronic communication field, relate in particular to a kind of under high-frequency the constant-temperature crystal oscillator device of working stability.

Background technology

At present the design weak point of constant-temperature crystal oscillator device is poor in high frequency band (more than the 80M) stability that works long hours, and can not reach customer requirements.Present domestic best high frequency constant-temperature crystal oscillator, index are that day is aging: 0.01ppm, annual aging: 0.1ppm.Phase noise 100K place-140dBC/Hz, temperature characterisitic can't be implemented in high frequency band and keep product work high stability, and small product size is big, the manufacturing cost height at 5E-08.

Summary of the invention

For overcoming the deficiencies in the prior art, the utility model embodiment provides a kind of constant temperature phase-locked crystal resonator, adopts new circuit structure design, can keep long working stability degree at high frequency band, and have low phase noise.

The utility model embodiment provides a kind of constant temperature phase-locked crystal resonator, and it comprises constant temperature control circuit, mark frequency oscillator circuit, PLL phase lock circuitry, VCO output circuit, power control circuit; Described constant temperature control circuit connects mark frequency oscillator circuit, PLL phase lock circuitry, VCO output circuit successively, and described power control circuit provides stable voltage for each circuit; The phase-locked crystal resonator of described constant temperature reaches working stability under high frequency environment by the described PLL phase lock circuitry control of low phase noise.

Further, described mark frequency oscillator circuit comprises high stable crystal resonator X1, an improved Ke Er oscillating circuit now; Described improved Ke Er now in the oscillating circuit: inductance L 4 and capacitor C 14 series connection constitute the B moulds and suppress networks, produce the B mould frequency that suppresses overtone crystal; Inductance L 5 and capacitor C 17 formation harmonic suppression networks in parallel produce and suppress the overtone crystal harmonic frequency; Inductance L 2 in parallel, capacitor C 13, capacitor C 12 constitute the frequency-selecting output network; Resistance R 11, capacitor C 3, resistance R 12, capacitor C 11 constitute filter circuit.Described mark frequency oscillator circuit provides effectively stable standard oscillation frequency signal for the PLL phase lock circuitry.

Further, described constant temperature control circuit is included in computing comparison amplifying circuit, heating power pipe, thermistor and the crystal that connects on the circuit substrate.Described constant temperature control circuit provides stable temperature environment for the mark frequency oscillator circuit produces the standard oscillation frequency signal, makes the standard oscillation frequency signal more stable.

Further, described PLL phase lock circuitry comprises that 12F629 model chip and LMX2306 model chip connect to form, the standard oscillation frequency signal of the phase-locked crystal oscillator of described constant temperature is by the input of LMX2306 model chip the 8th pin, and the voltage controlled frequency signal is imported by LMX2306 model chip the 6th pin; Described standard oscillation frequency signal and voltage controlled frequency signal carry out the mixing analysis in LMX2306 model chip.Read the single-chip microcomputer prestored information, from the voltage-controlled capister of LMX2306 model chip the 2nd pin Output Tracking Control voltage to described VCO output circuit, the frequency of regulating 131.04MHz reaches the effect of two frequency tracking locks.Voltage-controlled voltage carries out Filtering Processing makes the product phase noise improve 5dBc/Hz.

Further again, described VCO output circuit comprises voltage-controlled main vibration circuit, two-stage cascode level selective frequency amplifier circuit, T type filter circuit, voltage-controlled regulating circuit and the impedance matching output circuit that connects successively.Make product that better impedance matching ability and load capacity be arranged.

Further, improved Ke Er of described mark frequency oscillator circuit also comprises in the oscillating circuit now: the frequency modulation network, and the voltage of regulating diode D2 by variable resistor RV1 current potential changes capacitance realization frequency modulation; Temperature compensation network, by a B value preferably the paster thermistor be placed on outside the thermostat, change the capacity of diode D1 according to the variation of external temperature, the influence that compensation produces the phase-locked crystal oscillator of constant temperature because of the external environment temperature.Can remedy the relatively poor product of temperature characterisitic effectively.

Implement the utility model embodiment, by adopting structural designs such as new constant temperature control circuit, mark frequency oscillator circuit, PLL phase lock circuitry, can allow the phase-locked crystal resonator of constant temperature keep working stability for a long time at high frequency band, and has a low phase noise, attainable index is that day is aging:＜0.001ppm, annual aging:＜0.03ppm.And phase noise is at 100K place-150dBc/Hz, and temperature characterisitic can reach＜1E-08 in batches.And can realize that small product size minimizes, the length of product can reach the 36*27*16 millimeter.The phase-locked crystal oscillator product cost of constant temperature also can be controlled by getting the raw materials ready, and can select for use the oscillating crystal of a general high target to get the raw materials ready, and need only change the voltage-controlled crystal (oscillator) of low index when making the different frequent points product, has significantly reduced production cost.

Description of drawings

Fig. 1 is the phase-locked crystal resonator structural representation of the constant temperature block diagram that the utility model embodiment provides;

Fig. 2 is the phase-locked crystal resonator each several part of the constant temperature circuit signal process chart that the utility model embodiment provides;

Fig. 3 is the mark frequency oscillator circuit connection diagram that the utility model embodiment provides;

Fig. 4 is the constant temperature control circuit connection diagram that the utility model embodiment provides;

Fig. 5 is that the constant temperature control circuit structure that the utility model embodiment provides is provided with schematic diagram;

Fig. 6 is the phase-locked crystal resonator product performance index of the constant temperature figure that the utility model embodiment provides.

Embodiment

For making this purpose of this utility model, technical scheme and advantage clearer, the utility model is described in further detail below in conjunction with accompanying drawing.

As shown in Figure 1, the utility model embodiment provides a kind of constant temperature phase-locked crystal resonator, comprises constant temperature control circuit 10, mark frequency oscillator circuit 20, PLL phase lock circuitry 30, VCO output circuit 40, power control circuit 50; Described constant temperature control circuit 10 connects mark frequency oscillator circuit 20, PLL phase lock circuitry 30, VCO output circuit 40 successively, and described power control circuit 50 usefulness stabilized voltage power supply IC provide stable voltage for constant temperature control circuit 10, mark frequency oscillator circuit 20, PLL phase lock circuitry 30, VCO output circuit 40; The phase-locked crystal resonator of described constant temperature reaches working stability under high frequency environment by the described PLL phase lock circuitry control of low phase noise.

The phase-locked crystal resonator each several part of described constant temperature circuit signal handling process as shown in Figure 2, the variations in temperature of described constant temperature control circuit control mark frequency oscillator circuit, described mark frequency oscillator circuit is the effective stable standard oscillation frequency signal of PLL phase lock circuitry input, VCO output circuit input voltage controlled frequency signal is given the PLL phase lock circuitry, in the PLL phase lock circuitry, carry out the mixing analysis together with described standard oscillation frequency signal, and then Output Tracking Control voltage is given the voltage-controlled capister of described VCO output circuit, the regulating circuit frequency reaches the effect of two frequency tracking locks, signal after the conciliation amplifies through the frequency-selecting of two-stage cascode level again, the filtering of T type, voltage-controlled adjusting is exported by impedance matching at last.

Concrete, as shown in Figure 3, above-mentioned mark frequency oscillator circuit 20 comprise a high stable crystal resonator X1 (frequency is 10MHz), improved Ke Er now oscillating circuit, also have transistor Q1 and peripheral auxiliary circuits.Described improved Ke Er now in the oscillating circuit: inductance L 4 and capacitor C 14 series connection constitute the B moulds and suppress networks, produce the B mould frequency that suppresses overtone crystal; Inductance L 5 and capacitor C 17 formation harmonic suppression networks in parallel produce and suppress the overtone crystal harmonic frequency; Inductance L 2 in parallel, capacitor C 13, capacitor C 12 constitute the frequency-selecting output network, and the phase-locked crystal oscillator product of this constant temperature is pure because of signal output, so adopt directly output.Resistance R 11, capacitor C 3, resistance R 12, capacitor C 11 constitute filter circuit, can reduce effectively more than the oscillator far-end phaser noise 3dBc.Described mark frequency oscillator circuit provides effectively stable standard oscillation frequency signal for the PLL phase lock circuitry.

Improved Ke Er also comprises in the oscillating circuit now in the described mark frequency oscillator circuit: the frequency modulation network, and the voltage of regulating diode D2 by variable resistor RV1 current potential changes capacitance realization frequency modulation; Temperature compensation network, comprise original paper compositions such as potentiometer RT1, by a B value preferably the paster thermistor be placed on outside the thermostat, change the capacity of diode D1 according to the variation of external temperature, the influence that compensation produces the phase-locked crystal oscillator of constant temperature because of the external environment temperature, said temperature compensating network circuit can use when product requirement higher temperature characteristic.

Mark frequency oscillator circuit 20 is an important component part in the phase-locked crystal oscillator of whole constant temperature, be the benchmark of all signals, its stability directly influences the stability of product, also depends on choosing of crystal simultaneously, therefore it is very important clearly selecting its index, adopts the SC crystal of import can satisfy fully.Described mark frequency oscillator circuit circuit will be carried out isolation processing when design circuit, reduce the interference of high-frequency signal to it.

As shown in Figure 4, described constant temperature control circuit 10 is included in computing comparison amplifying circuit IC1, heating power pipe, thermistor, the crystal Q2 that connects successively on the circuit substrate.Its structure setting as shown in Figure 5, crystal 1 and heating power pipe 2 are arranged on the thermostat 3 of circuit substrate 5 among Fig. 5, paster thermistor 4 is placed on outside the thermostat and closely contacts with thermostat 3, accurately detected temperatures changes the heat that adds by computing comparison amplifying circuit control heating power pipe, makes crystal 1 be operated in stable temperature and is issued to frequency stabilization.

Described PLL phase lock circuitry 30 is made up of 12F629 model chip and LMX2306 model chip, the standard oscillation frequency signal of the phase-locked crystal oscillator of described constant temperature is by the input of LMX2306 model chip the 8th pin, and the voltage controlled frequency signal is imported by LMX2306 model chip the 6th pin; Described standard oscillation frequency signal and voltage controlled frequency signal carry out the mixing analysis in LMX2306 model chip, and read the single-chip microcomputer prestored information, from the voltage-controlled capister of LMX2306 model chip the 2nd pin Output Tracking Control voltage to described VCO output circuit, the frequency of regulating 131.04MHz reaches the effect of two frequency tracking locks.

Described VCO output circuit 40 comprises voltage-controlled main vibration circuit, two-stage cascode level selective frequency amplifier circuit, T type filter circuit, voltage-controlled regulating circuit and the impedance matching output circuit that connects successively.

The utility model is by adopting structural designs such as new constant temperature control circuit, mark frequency oscillator circuit, PLL phase lock circuitry, can allow the phase-locked crystal resonator of constant temperature keep long working stability degree at high frequency band, and having low phase noise, the attainable index of product is as shown in Figure 6.

The above is a preferred implementation of the present utility model; certainly can not limit the interest field of the utility model with this; should be understood that; for those skilled in the art; under the prerequisite that does not break away from the utility model principle; can also make some improvement and change, these improvement and change also are considered as protection range of the present utility model.

Claims

1, the phase-locked crystal resonator of a kind of constant temperature is characterized in that, comprises constant temperature control circuit, mark frequency oscillator circuit, PLL phase lock circuitry, VCO output circuit, power control circuit; Described constant temperature control circuit connects mark frequency oscillator circuit, PLL phase lock circuitry, VCO output circuit successively, and described power control circuit provides stable voltage for each circuit; The phase-locked crystal resonator of described constant temperature reaches working stability under high frequency environment by the described PLL phase lock circuitry control of low phase noise.

2, the phase-locked crystal resonator of constant temperature according to claim 1 is characterized in that, described mark frequency oscillator circuit comprises high stable crystal resonator X1, an improved Ke Er oscillating circuit now; Described improved Ke Er now in the oscillating circuit: inductance L 4 and capacitor C 14 series connection constitute the B moulds and suppress networks, produce the B mould frequency that suppresses overtone crystal, inductance L 5 and capacitor C 17 formation harmonic suppression networks in parallel, produce and suppress the overtone crystal harmonic frequency, inductance L 2 in parallel, capacitor C 13, capacitor C 12 constitute the frequency-selecting output network, and resistance R 11, capacitor C 3, resistance R 12, capacitor C 11 constitute filter circuit; Described mark frequency oscillator circuit provides effectively stable standard oscillation frequency signal for the PLL phase lock circuitry.

3, the phase-locked crystal resonator of constant temperature according to claim 2, it is characterized in that, improved Ke Er of described mark frequency oscillator circuit also comprises in the oscillating circuit now: the frequency modulation network, and the voltage of regulating diode D2 by variable resistor RV1 current potential changes capacitance realization frequency modulation; Temperature compensation network, by a B value preferably the paster thermistor be placed on outside the thermostat, change the capacity of diode D1 according to the variation of external temperature, the influence that compensation produces the phase-locked crystal resonator of constant temperature because of the external environment temperature.

4, the phase-locked crystal resonator of constant temperature according to claim 1, it is characterized in that, described constant temperature control circuit is included in the computing that connects on the circuit substrate and compares amplifying circuit, heating power pipe, thermistor and crystal, and described constant temperature control circuit provides stable temperature environment for the mark frequency oscillator circuit produces the standard oscillation frequency signal.

5, the phase-locked crystal resonator of constant temperature according to claim 1, it is characterized in that described VCO output circuit comprises voltage-controlled main vibration circuit, two-stage cascode level selective frequency amplifier circuit, T type filter circuit, voltage-controlled regulating circuit and the impedance matching output circuit that connects successively.

6, the phase-locked crystal resonator of constant temperature according to claim 1, it is characterized in that, described PLL phase lock circuitry comprises that 12F629 model chip and LMX2306 model chip connect to form, the standard oscillation frequency signal of the phase-locked crystal oscillator of described constant temperature is by the input of LMX2306 model chip the 8th pin, and the voltage controlled frequency signal is imported by LMX2306 model chip the 6th pin; Described standard oscillation frequency signal and voltage controlled frequency signal carry out the mixing analysis in LMX2306 model chip, and then Output Tracking Control voltage reaches two effects of tracking locks frequently for described VCO output circuit, regulating frequency.