JP2003069422A - Reference frequency generating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reference frequency generating apparatus with low power consumption that can generate a synchronizing signal with high accuracy and a reference frequency signal with high stability and reduce a time until the reference frequency is stabilized at starting. SOLUTION: A GPS receiver 2 generates an intermediate frequency signal A and a 1-second pulse signal B synchronously with the coordinated universal time, a frequency converter 4 converts an oscillation signal of a voltage- controlled crystal oscillator 3 covered by a metal-made case 100 into a signal A' with the intermediate frequency, a phase comparator 5 compares the phase of the intermediate frequency signal A with that of the signal A', a crystal voltage controller 6 controls a voltage applied to the voltage-controlled crystal oscillator 3 so as to synchronize the signal A' with the intermediate frequency A on the basis of the result of comparison, a Peltier current controller 9 controls a current supplied to a Peltier element 7 on the basis of the measurement result of an in-case temperature sensor 8 to bring the temperature in the metal-made case 100 to a target setting value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reference frequency generator.

[0002]

2. Description of the Related Art A radio base station for a mobile phone requires an oscillator for generating a highly accurate synchronizing signal and a highly stable reference frequency for forming a carrier frequency depending on the system system. And therefore GPS
(Global Positioning System
m) A receiving device is used. The oscillator that forms the reference frequency is a heater-type crystal oscillator with an oven (OCXO: Open Controlled Cry).
stal Oscillator) was used.

[0003]

However, in the OCXO, since the crystal oscillator is warmed to a temperature higher than the operating temperature range of the device in which it is incorporated, it takes time for the temperature to stabilize at the time of startup, and power consumption is large. was there. In addition, OCXO guarantees long-term stability.
There is also a drawback that adjustment and aging after manufacturing take time and effort.

The present invention has been made in view of the above circumstances, and an object thereof is to generate a highly accurate synchronization signal and a highly stable reference frequency, and to stabilize the reference frequency at the time of startup. It is an object of the present invention to provide a reference frequency generator with reduced power consumption and low power consumption.

[0005]

The invention of claim 1 is the GP
GPS antenna for receiving S satellite radio waves and received GP
A GPS receiver that forms an intermediate frequency signal and a synchronous pulse signal that is synchronized with the Coordinated Universal Time based on the S satellite radio wave, a voltage-controlled crystal oscillator whose oscillation frequency is controlled by an applied voltage, and the oscillation signal. To a signal of an intermediate frequency, and a phase comparator for comparing the phase of the intermediate frequency signal formed by the GPS receiver with the phase of the signal formed by the frequency converter and outputting the comparison result. And a crystal voltage for controlling the voltage applied to the voltage controlled crystal oscillator so that the signal formed by the frequency converter is synchronized with the intermediate frequency signal formed by the GPS receiver based on the output signal of the phase comparator. A controller,
A metal case that covers the voltage controlled crystal oscillator so as not to directly contact the outside air, a Peltier element that is in close contact with the metal case, a case temperature sensor that measures the temperature inside the metal case, and a temperature inside the metal case. A Peltier current controller for controlling a current flowing through the Peltier element based on the measurement result of the temperature sensor in the case to bring the temperature to a predetermined temperature, and a reference frequency signal and the synchronization pulse signal according to the oscillation signal. It is characterized by outputting and.

According to the second aspect of the present invention, a GPS antenna for receiving a GPS satellite radio wave and a G for forming a synchronous pulse signal synchronized with the Coordinated Universal Time based on the received GPS satellite radio wave.
A PS receiver, a voltage-controlled crystal oscillator whose oscillation frequency is controlled by an applied voltage, a frequency converter which converts the oscillation signal into a signal having the same frequency as the synchronization pulse signal, and the GPS receiver A phase comparator that compares the phase of the formed sync pulse signal with the phase of the signal formed by the frequency converter and outputs the comparison result, and the frequency converter based on the output signal of the phase comparator The crystal voltage controller for controlling the voltage applied to the voltage controlled crystal oscillator so as to synchronize the generated signal with the synchronizing pulse signal formed by the GPS receiver, and the crystal voltage controller for covering the voltage controlled crystal oscillator so as not to directly touch the outside air. With a metal case
A Peltier element in close contact with the metal case, an in-case temperature sensor for measuring the temperature in the metal case, and a measurement result of the in-case temperature sensor to bring the temperature in the metal case to a predetermined temperature. A Peltier current controller for controlling a current flowing through the Peltier element, and outputting a reference frequency signal and the synchronization pulse signal according to the oscillation signal.

According to a third aspect of the present invention, in the first aspect of the present invention, the frequency converter outputs an oscillation signal of the voltage controlled crystal oscillator having the same frequency as the intermediate frequency signal and the same frequency as the synchronization pulse signal. It is characterized in that it is converted into a signal.

According to a fourth aspect of the invention, in the third aspect of the invention, the synchronization accuracy of the synchronization pulse signal formed by the GPS receiver or the stability of the intermediate frequency signal cannot be guaranteed, and the GPS satellite radio wave is not received. And a satellite non-reception detector that detects that the satellite non-reception detector outputs a synchronization pulse signal formed by the GPS receiver when the satellite non-reception detector does not detect the non-reception state. When a non-reception state is detected, a satellite non-reception controller that outputs a signal of the same frequency as the synchronization pulse signal converted from the oscillation signal by the frequency converter is provided, and the satellite non-reception detector indicates the non-reception state. When detected, the crystal voltage controller holds the voltage applied to the voltage controlled crystal oscillator at the voltage before detection of the unreceived state.

According to a fifth aspect of the invention, in the third aspect of the invention, the synchronization accuracy of the synchronization pulse signal formed by the GPS receiver or the stability of the intermediate frequency signal cannot be guaranteed, and the GPS satellite radio wave is not received. A satellite non-reception detector for detecting that the satellite non-reception detector detects a non-reception state by outputting a signal having the same frequency as the synchronization pulse signal converted from the oscillation signal by the frequency converter. In this case, the crystal voltage controller holds the voltage applied to the voltage controlled crystal oscillator at the voltage before detection of the unreceived state.

A sixth aspect of the present invention is the reference frequency converter according to any one of the first to fifth aspects, wherein the oscillation frequency of the oscillation signal of the voltage controlled crystal oscillator is converted to a reference frequency to form a reference frequency signal. It is characterized by being provided.

According to a seventh aspect of the invention, in the invention according to any one of the first to sixth aspects, the metal case directly exposes the voltage-controlled crystal oscillator and a component whose performance is easily influenced by a change in outside air temperature. It is characterized by being covered so that it does not exist.

According to an eighth aspect of the present invention, in the invention of any of the first to seventh aspects, the Peltier current controller sets the temperature in the metal case measured by the temperature sensor in the case to the voltage controlled crystal oscillator. A current flowing through the Peltier element is controlled so as to reach an adjusted temperature at which adjustment is performed at the time of manufacturing the constituent crystal unit.

According to a ninth aspect of the present invention, in the invention according to any one of the first to eighth aspects, the voltage-controlled crystal oscillator has temperature correction means for suppressing fluctuations in oscillation frequency due to changes in operating environment temperature. To do.

According to a tenth aspect of the present invention, in any one of the first to ninth aspects, an ambient temperature sensor for measuring the ambient temperature of the metal case is provided, and the Peltier current controller controls the temperature in the metal case. It is characterized in that the current flowing through the Peltier element is controlled to bring the temperature to a temperature based on the ambient temperature measured by the ambient temperature sensor.

According to an eleventh aspect of the invention, in the tenth aspect of the invention, the Peltier current controller sets the temperature in the metal case to an average temperature of the ambient temperature measured by the ambient temperature sensor in a predetermined period. In addition, the current flowing through the Peltier element is controlled.

According to a twelfth aspect of the present invention, in the tenth aspect of the present invention, the Peltier current controller causes the temperature in the metal case to flow to the Peltier element so as to approach the ambient temperature measured by the ambient temperature sensor. It is characterized by controlling the current.

The invention of claim 13 is the same as claim 11 or 1.
In the invention of 2, the satellite non-reception detector for detecting that the synchronization accuracy of the synchronization pulse signal formed by the GPS receiver or the stability of the intermediate frequency signal cannot be guaranteed and the GPS satellite radio wave is in the non-reception state is provided. When the satellite non-reception detector detects a non-reception state, the Peltier current controller holds the temperature in the metal case at the temperature before the detection of the non-reception state.

According to a fourteenth aspect of the present invention, in the thirteenth aspect of the present invention, the printed circuit board is provided with one printed circuit board on which components other than the GPS antenna are arranged, and the printed circuit board surrounds the metal case arranged on the circuit board. Is characterized in that holes are formed in the substrate surface.

A fifteenth aspect of the present invention is characterized in that, in any one of the first to fourteenth aspects, the metal case is provided with a heat insulating material on an outer wall or an inner wall.

According to a sixteenth aspect of the present invention, in any one of the first to fifteenth aspects of the present invention, the target predetermined temperature in the metal case and the temperature in the metal case measured by the temperature sensor in the case are set. When the difference is larger than a predetermined difference, the Peltier current controller increases the current flowing through the Peltier element.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) In this embodiment, the GPS (G
(Global Positioning System)
The satellite radio waves are received, and based on the received satellite radio waves, a highly stable intermediate frequency signal and Coordinated Universal Time (UTC:
High accuracy by synchronizing the intermediate frequency signal generated by the oscillation frequency of the voltage controlled crystal oscillator with the intermediate frequency signal output by the device that forms the synchronization pulse signal of 1 pps (1 pulse / second) synchronized with the ral Time Coordinated). Generate the reference frequency of
The voltage-controlled crystal oscillator is housed in a metal case that can perform temperature control using a Peltier element, which makes the reference frequency more stable and shortens the time until the reference frequency stabilizes at start-up with low power consumption. It is characterized by being a device, and its circuit configuration is shown in FIG.

The fundamental frequency generator of this embodiment is a GP
GPS antenna 1 for receiving S satellite radio waves and received G antenna
A GPS receiver 2 that forms an intermediate frequency signal A and a 1-second pulse signal B as a synchronization pulse signal that is synchronized with UTC based on PS satellite radio waves, and a voltage whose oscillation frequency is controlled by an applied voltage. Control crystal oscillator 3
, A frequency converter 4 for converting an oscillation signal output from the voltage controlled crystal oscillator 3 into an intermediate frequency signal A ′, a phase of the intermediate frequency signal A formed by the GPS receiver 2, and a signal formed by the frequency converter 4. The phase comparator 5 that compares the phase of A'and outputs the comparison result, and the signal A'formed by the frequency converter 4 based on the output signal of the phase comparator 5
A crystal voltage controller 6 that controls the voltage applied to the voltage-controlled crystal oscillator 3 so as to synchronize with the intermediate frequency signal A formed by the receiver 2, and a metal that covers the voltage-controlled crystal oscillator 3 so as not to directly contact the outside air. Case 100 and metal case 1
Peltier element 7 in close contact with 00, an in-case temperature sensor 8 for measuring the temperature in the metal case 100, and a measurement result of the in-case temperature sensor 8 for keeping the temperature in the metal case 100 at a target set value. A Peltier current controller 9 for controlling the current flowing through the Peltier element 7.

Next, the operation of this embodiment will be described. First, the GPS receiver 2 receives an intermediate frequency signal A with high stability from GPS satellite radio waves received by the GPS antenna 1.
And a 1-second pulse signal B synchronized with UTC. Generally, the one-second pulse signal B formed by the GPS receiver 2
Can obtain a synchronization accuracy of ± several tens ns with respect to UTC. A highly accurate sync pulse signal is required between wireless base stations of mobile phones, and this 1-second pulse signal B is output to the outside as a sync pulse signal.

Then, the oscillation signal output from the voltage controlled crystal oscillator 3 is output to the outside as the reference frequency signal C having a high stability necessary for forming the carrier frequency. Here, if the control voltage applied to the voltage controlled crystal oscillator 3 by the crystal voltage controller 6 is constant, the oscillation frequency can be set to a constant frequency. However, in reality, the oscillation frequency fluctuates due to changes in the operating environment temperature. To do. Therefore, the voltage-controlled crystal oscillator 3 is covered with the metal case 100 in order to block heat from the outside air. However, the temperature equivalent to the outside air will eventually be reached only by covering with the metal case 100, so that the case temperature measured by the case temperature sensor 8 installed inside the metal case 100 is kept at the target set value. The Peltier element 7 is brought into close contact with the Peltier element 7, and the current flowing through the Peltier element 7 is controlled by the Peltier current controller 9 to control the heating / cooling capacity of the Peltier element 7.

Further, the oscillation signal (reference frequency signal C) output from the voltage controlled crystal oscillator 3 is converted by the frequency converter 4 into the intermediate frequency signal A'having the same frequency as the intermediate frequency signal A, and the intermediate frequency signal. A and the signal A ′ are compared in phase by the phase comparator 5. The phase comparator 5 outputs the comparison result to the crystal voltage controller 6, and the crystal voltage controller 6
Applies a control voltage to the voltage controlled crystal oscillator 3 so that the signal A ′ is synchronized with the intermediate frequency signal A. in this way,
By constantly synchronizing the signal A ′ with the intermediate frequency signal A, the reference frequency of the reference frequency signal C can achieve a stability of 10 ⁻¹⁰ or more in a few seconds.

In the prior art, in order to maintain the stability of the reference frequency to the same extent as in the present invention, an expensive heater-type crystal oscillator with an oven (OCXO: Open Cont) is used.
rolled Crystal Oscilato
It was necessary to use r). The OCXO has an internal heater for maintaining the temperature in the constant temperature bath at a temperature equal to or higher than the use environment temperature, and it takes several tens of minutes until the internal temperature stabilizes, and the current consumption is as large as several hundred mA. In contrast to such a conventional technique, in the present embodiment, the metal case 100
If the target set value of the internal temperature is set to the room temperature level, the time until the reference frequency becomes stable can be several tens of seconds or less, and the current consumption of the Peltier element can be brought close to zero.

(Second Embodiment) The circuit configuration of the present embodiment is shown in FIG. 2, and the basic configuration is substantially the same as that of the first embodiment. In the present embodiment, the GPS receiver 2 forms only the 1-second pulse signal B which is a synchronization pulse signal. Then, the oscillation signal (reference frequency signal C) output from the voltage controlled crystal oscillator 3
Is converted into a signal B ′ having the same frequency as the 1-second pulse signal B by the frequency converter 4, and the phases of the 1-second pulse signal B and the signal B ′ are compared by the phase comparator 5. The phase comparator 5 outputs the comparison result to the crystal voltage controller 6, and the crystal voltage controller 6 applies a control voltage to the voltage controlled crystal oscillator 3 so that the signal B ′ is synchronized with the 1-second pulse signal B.

When phase comparison is performed using the 1-second pulse signal B as in the present embodiment, it takes several tens to several tens of seconds until the signal B ′ is synchronized with the 1-second pulse signal B, as compared with the first embodiment. Although slightly inferior, even if the GPS receiver 2 that does not form an intermediate frequency signal is used as the reference frequency generation device, a high stability reference frequency can be generated.

(Embodiment 3) The circuit configuration of this embodiment is shown in FIG. 3, and the basic configuration is substantially the same as that of the first embodiment. In the present embodiment, the oscillation signal output from the voltage controlled crystal oscillator 3 is not used as the reference frequency signal C as in the first embodiment, but the voltage controlled crystal oscillator 3 having an oscillation frequency that is easily available is used. The reference frequency converter 10 is connected to the subsequent stage of the voltage controlled crystal oscillator 3 to output the reference frequency signal C obtained by converting the frequency of the oscillation signal to the reference frequency to the outside. Further, a plurality of reference frequencies can be generated by preparing a plurality of reference frequency converters 10 instead of one.

(Embodiment 4) The circuit configuration of this embodiment is shown in FIG. 4, the basic configuration is substantially the same as that of the first embodiment, and the same reference numerals are given to the same configurations and the description thereof is omitted. In the present embodiment, the oscillation signal (reference frequency signal C) output by the voltage controlled crystal oscillator 3 is an intermediate frequency signal A ′ having the same frequency as the intermediate frequency signal A by the frequency converter 4, and the 1-second pulse signal B. Is converted into a signal B ′ having the same frequency as The signal A ′ is GP as in the first embodiment.
Intermediate frequency signal A formed by S receiver 2 and phase comparator 5
, The phase comparator 5 outputs the comparison result to the crystal voltage controller 6, and the crystal voltage controller 6 controls the voltage controlled crystal oscillator 3 so that the signal A ′ is synchronized with the intermediate frequency signal A.
A control voltage is applied to.

Further, when the reception condition of the GPS satellite radio wave becomes poor and the synchronization accuracy of the 1-second pulse signal B formed by the GPS receiver 2 cannot be guaranteed, the GPS satellite radio wave is not received yet. Satellite unreceived detector 11 to detect
When the satellite unreceived detector 11 does not detect the unreceived state, the 1-second pulse signal B formed by the GPS receiver 2 is selected as an external output, and the satellite unreceived detector 11 detects the unreceived state. In this case, the satellite non-reception controller 12 that selects the 1-second pulse signal B ′ formed by the frequency converter 4 as an external output is provided. Furthermore, the satellite unreceived detector 11
4 is connected to the crystal voltage controller 6 as shown by the dotted line in FIG. 4, and when the unreceived state is detected, the crystal voltage controller 6 applies the voltage applied to the voltage controlled crystal oscillator 3 to the unreceived state. Is held at the voltage before detection. Therefore, GP
It is possible to generate a high-stability reference frequency signal C and a highly accurate 1-second pulse signal B ′ even when S satellite radio waves cannot be received, and the reference frequency signal C and the 1-second pulse signals B and B ′ are always generated.
Either of them can be output to the outside. In this embodiment, the satellite unreceived detector 11 is
Although the reception state of the GPS satellite radio wave is detected by the synchronization accuracy of the second pulse signal B, the same effect can be obtained even if the reception state of the GPS satellite radio wave is detected by the stability of the intermediate frequency signal A.

(Embodiment 5) The circuit configuration of the present embodiment is shown in FIG. 5, the basic configuration is substantially the same as that of the first embodiment, and the same components are designated by the same reference numerals and the description thereof will be omitted. In the present embodiment, the oscillation signal (reference frequency signal C) output by the voltage controlled crystal oscillator 3 is an intermediate frequency signal A ′ having the same frequency as the intermediate frequency signal A by the frequency converter 4, and the 1-second pulse signal B. Is converted into a signal B ′ having the same frequency as The signal A ′ is GP as in the first embodiment.
Intermediate frequency signal A formed by S receiver 2 and phase comparator 5
, The phase comparator 5 outputs the comparison result to the crystal voltage controller 6, and the crystal voltage controller 6 controls the voltage controlled crystal oscillator 3 so that the signal A ′ is synchronized with the intermediate frequency signal A.
A control voltage is applied to.

When the GPS satellite radio wave reception condition deteriorates and the synchronization accuracy of the one-second pulse signal B formed by the GPS receiver 2 cannot be guaranteed, the GPS satellite radio wave is not yet received. Satellite unreceived detector 11 to detect
Is equipped with. Further, the output of the satellite unreceived detector 11 is connected to the crystal voltage controller 6 as shown by the dotted line in FIG. 4, and when the unreceived state is detected, the crystal voltage controller 6 outputs to the voltage controlled crystal oscillator 3. The applied voltage is maintained at the voltage before detecting the unreceived state. Therefore, even when the GPS satellite radio wave cannot be received, the highly stable reference frequency signal C and the highly accurate 1-second pulse signal B ′ can be generated, and
The reference frequency signal C and the 1-second pulse signal B ′ can be output to the outside. Further, the need for the switching procedure of the 1-second pulse signals B and B ′ depending on the reception state of GPS satellite radio waves as in the fourth embodiment is eliminated. In the present embodiment, the satellite unreceived detector 11 detects the reception state of the GPS satellite radio wave based on the synchronization accuracy of the 1-second pulse signal B, but the reception of the GPS satellite radio wave depends on the stability of the intermediate frequency signal A. The same effect can be obtained by detecting the state.

(Embodiment 6) The circuit configuration of this embodiment is shown in FIG. 6, and the basic configuration is substantially the same as that of the first embodiment. The reference device for setting the reference temperature and the operational amplifier used in the Peltier current controller 9 are easily affected by the operating environment temperature, so that the temperature in the metal case 100 may deviate from the target set value. Therefore, in this embodiment, in addition to the voltage-controlled crystal oscillator 3 and the temperature sensor 8 in the case, the Peltier current controller 9 is provided in the metal case 10 for heat insulation from the outside air.
It is stored in 0. However, the Peltier current controller 9 also uses a component serving as a current source of the Peltier element 7, and such a component generates heat to cause a metal case 100.
Since the temperature inside fluctuates, it is better to install it outside the metal case 100.

Also, what is housed in the metal case 100 is
Not only the components of the Peltier current controller 9 but also components such as the components forming the reference frequency of the reference frequency signal C used in the crystal voltage controller 6 that are easily influenced by the operating environment temperature are inside the metal case 100. The higher the stability, the higher the reference frequency can be obtained.

(Embodiment 7) In Embodiments 1 to 6,
The crystal oscillator incorporated in the voltage controlled crystal oscillator 3 is adjusted at room temperature level at the time of manufacturing, and if it is used at this adjustment temperature, a high-stability reference frequency can be obtained.
Therefore, the target set value of the temperature in the metal case 100 is set as the adjustment temperature at the time of manufacturing the crystal unit, and the Peltier current controller 9 sets the Peltier current controller 9 so that the temperature in the metal case 100 maintains the set temperature, that is, the adjustment temperature. By controlling the current flowing through the element 7, it is possible to obtain a reference frequency with higher stability.

Furthermore, the crystal oscillator incorporated in the voltage controlled crystal oscillator 3 is a crystal oscillator (TCX) having temperature correction means for suppressing frequency fluctuations due to changes in the operating environment temperature.
O: Temperature Compensation
n Crystal Oscillator), fluctuations in the oscillation frequency can be suppressed even when the target set value of the temperature inside the metal case 100 and the adjusted temperature during manufacturing of the crystal unit are deviated.

(Embodiment 8) The circuit configuration of this embodiment is shown in FIG. 7, the basic configuration is substantially the same as that of the first embodiment, and the same reference numerals are given to the same configurations and the description thereof is omitted. In the present embodiment, the ambient temperature sensor 13 is provided to measure the ambient temperature of the metal case 100, and the Peltier current controller 9 determines the inside temperature of the metal case 100 based on the ambient temperature measured by the ambient temperature sensor 13. By making the target setting value of the temperature of 1 variable, the current consumption of the Peltier device 7 can be reduced.

As an example, by setting the target set value of the temperature inside the metal case 100 to the average temperature of the ambient temperature measured by the ambient temperature sensor 13 in a predetermined period, for example, the average temperature of the ambient temperature of the day before the previous day, Alternatively, by slowly approaching the ambient temperature measured by the ambient temperature sensor 13, the variation amount of the temperature in the metal case 100 is suppressed to be smaller than the variation amount of the ambient temperature.
Current consumption can be reduced. Furthermore, if the crystal oscillator incorporated in the voltage controlled crystal oscillator 3 has a temperature correction means that suppresses frequency fluctuations due to changes in the operating environment temperature, the effect on the stability of the reference frequency is also reduced.

(Ninth Embodiment) The circuit configuration of this embodiment is shown in FIG. 8, and the basic configuration is substantially the same as that of the seventh embodiment. The same components are designated by the same reference numerals and the description thereof will be omitted. In the present embodiment, when the GPS satellite radio wave reception condition deteriorates and the synchronization accuracy of the 1-second pulse signal B formed by the GPS receiver 2 cannot be guaranteed, the GPS satellite radio wave is not yet received. The satellite non-reception detector 11 that detects the signal and outputs the detection result to the Peltier current controller 9. When the GPS satellite radio wave is in the non-reception state, the Peltier current controller 9 keeps the temperature inside the metal case 100 measured by the in-case temperature sensor 8 at the temperature before detecting the non-reception state. The stability of the reference frequency can be maintained by controlling the current flowing through the Peltier element 7.

In this embodiment, the satellite non-reception detector 11 uses the GP of the 1-second pulse signal B for the synchronization accuracy.
Although the reception state of the S satellite radio wave is detected, the same effect can be obtained even if the reception state of the GPS satellite radio wave is detected depending on the stability of the intermediate frequency signal A.

(Embodiment 10) This embodiment is the first embodiment.
9 to 9, the components other than the GPS antenna 1 are mounted on one printed circuit board 103 as shown in the external view of FIG. 9, and the same as in the first to ninth embodiments. The same reference numerals are given to the configurations and the description thereof will be omitted. In the present embodiment, the printed circuit board 1 is provided by the box-shaped metal case 100 having an opening on the printed circuit board 103 side.
03, the voltage controlled crystal oscillator 3, the temperature sensor 8 in the case (in the sixth embodiment, the Peltier current controller 9).
By covering only the upper part of the component (including), the structure of the entire device can be simplified and the size can be reduced as compared with the case where the entire component is covered by the metal case 100. Furthermore, the heat dissipation performance can be improved by bringing the Peltier element 7 into close contact with the upper surface of the metal case 100 and providing the heat dissipation fin 101 on the upper surface of the Peltier element 7.

In addition, the metal case 1 of the printed circuit board 103
00 holes 102 formed around the mounting portion and a heat insulating material (not shown) provided on the inner wall or outer wall of the metal case 100 where the Peltier element 7 is not adhered,
It is possible to prevent heat conduction to the printed circuit board 103 and heat exchange with the outside air, and it is possible to suppress temperature fluctuations inside the metal case 100.

Here, the Peltier current controller 9 sets the target set value of the temperature in the metal case 100 and the temperature sensor 8 in the case.
The current flowing through the Peltier element 7 is made variable according to the difference from the temperature measured in the above, and the heating / cooling capacity of the Peltier element 7 is made variable, and the amplification factor of the output at this time is fixed to a constant value. However, when the difference between the set temperature and the measured temperature is large, it takes time for the temperature in the metal case 100 to reach the target set value. Therefore, in the present embodiment, when the temperature difference is a certain value or more, the Peltier The current controller 9 is
In order to make the current flowing through the Peltier device 7 larger than usual, the amplification factor of the output is controlled to be large, and when the temperature difference becomes a certain value or less, it is returned to the normal amplification factor. By performing such control, it is possible to further shorten the time until the reference frequency stabilizes at the time of startup.

[0046]

According to the invention of claim 1, a GPS antenna for receiving GPS satellite radio waves, and a GPS receiver for forming an intermediate frequency signal and a synchronous pulse signal synchronized with Coordinated Universal Time based on the received GPS satellite radio waves. A voltage controlled crystal oscillator whose oscillation frequency is controlled by an applied voltage, a frequency converter for converting the oscillation signal into an intermediate frequency signal, and a phase of the intermediate frequency signal formed by the GPS receiver. The phase of the signal formed by the frequency converter is compared, and the GPS receiver receives the signal formed by the frequency converter based on the output signal of the phase comparator, which outputs the comparison result. A crystal voltage controller for controlling the voltage applied to the voltage controlled crystal oscillator so as to synchronize with the formed intermediate frequency signal, and the voltage controlled crystal oscillator In order to keep the temperature inside the metal case at a predetermined temperature, a metal case covered so as not to touch, a Peltier element in close contact with the metal case, a temperature sensor inside the case for measuring the temperature inside the metal case, A Peltier current controller for controlling the current flowing through the Peltier element based on the measurement result of the temperature sensor in the case,
Since the reference frequency signal corresponding to the oscillation signal and the synchronization pulse signal are output, the Coordinated Universal Time (UTC: Univ)
It is possible to generate a synchronization pulse signal with high synchronization accuracy and a reference frequency with high stability with respect to personal time coordinated (ERS), and a conventional heater-type crystal oscillator with an oven (OCXO: Open Control).
(olled Crystal Oscillator)
By using a voltage-controlled crystal oscillator to generate the reference frequency instead of the oscillator, there is no need for post-fabrication adjustments or aging of the oscillator, and it is possible to guarantee long-term maintenance of constant frequency with high stability by voltage control. it can. Further, since the Peltier device is provided in the metal case to control the temperature of the signal generation source, lower power consumption can be achieved as compared with the prior art, and the time until the reference frequency stabilizes at start-up can be greatly shortened. You can Further, if a Peltier element is provided outside the metal case, the case volume can be made smaller than that of the OCXO, so that there is an effect that the power consumption can be further reduced.

According to a second aspect of the present invention, a GPS antenna that receives GPS satellite radio waves and a G pulse that forms a synchronous pulse signal synchronized with the Coordinated Universal Time based on the received GPS satellite radio waves.
A PS receiver, a voltage-controlled crystal oscillator whose oscillation frequency is controlled by an applied voltage, a frequency converter which converts the oscillation signal into a signal having the same frequency as the synchronization pulse signal, and the GPS receiver A phase comparator that compares the phase of the formed sync pulse signal with the phase of the signal formed by the frequency converter and outputs the comparison result, and the frequency converter based on the output signal of the phase comparator The crystal voltage controller for controlling the voltage applied to the voltage controlled crystal oscillator so as to synchronize the generated signal with the synchronizing pulse signal formed by the GPS receiver, and the crystal voltage controller for covering the voltage controlled crystal oscillator so as not to directly touch the outside air. With a metal case
A Peltier element in close contact with the metal case, an in-case temperature sensor for measuring the temperature in the metal case, and a measurement result of the in-case temperature sensor to bring the temperature in the metal case to a predetermined temperature. A GPS that does not form an intermediate frequency signal, since a Peltier current controller that controls the current flowing through the Peltier element is output, and the reference frequency signal and the synchronization pulse signal according to the oscillation signal are output.
Even if a receiver is used, a highly stable reference frequency can be generated, and the same effect as that of claim 1 can be obtained.

According to a third aspect of the present invention, in the first aspect of the present invention, the frequency converter outputs an oscillation signal of the voltage controlled crystal oscillator having the same frequency as the intermediate frequency signal and the same frequency as the synchronization pulse signal. Because it converts to a signal,
There is an effect that the reference frequency signal and the synchronization pulse signal can be generated even when GPS satellite radio waves cannot be received.

According to a fourth aspect of the invention, in the third aspect of the invention, the synchronization accuracy of the synchronization pulse signal formed by the GPS receiver or the stability of the intermediate frequency signal cannot be guaranteed, and the GPS satellite radio wave is not received. And a satellite non-reception detector that detects that the satellite non-reception detector outputs a synchronization pulse signal formed by the GPS receiver when the satellite non-reception detector does not detect the non-reception state. When a non-reception state is detected, a satellite non-reception controller that outputs a signal of the same frequency as the synchronization pulse signal converted from the oscillation signal by the frequency converter is provided, and the satellite non-reception detector indicates the non-reception state. When detected, the crystal voltage controller holds the voltage applied to the voltage controlled crystal oscillator at the voltage before the detection of the unreceived state, so when the GPS satellite radio wave cannot be received, the voltage is Holding a voltage applied to the control crystal oscillator voltage at the time can be received, GPS output of the synchronizing pulse signal
By switching from the output of the receiver to the output of the frequency converter, it is possible to generate a reference frequency signal with high stability and a synchronization pulse signal with high synchronization accuracy even when GPS satellite radio waves cannot be received. There is an effect that the signal can be output to the outside.

According to a fifth aspect of the invention, in the third aspect of the invention, the synchronization accuracy of the synchronization pulse signal formed by the GPS receiver or the stability of the intermediate frequency signal cannot be guaranteed, and the GPS satellite radio wave is not received. A satellite non-reception detector for detecting that the satellite non-reception detector detects a non-reception state by outputting a signal having the same frequency as the synchronization pulse signal converted from the oscillation signal by the frequency converter. In that case, since the crystal voltage controller holds the voltage applied to the voltage controlled crystal oscillator at the voltage before detection of the unreceived state, by always outputting the synchronization pulse signal formed by the frequency converter to the outside, According to the fourth aspect, there is an effect that it is not necessary to switch the synchronization pulse signal depending on the reception status of the GPS satellite radio wave.

A sixth aspect of the present invention is the reference frequency converter according to any one of the first to fifth aspects, wherein the oscillation frequency of the oscillation signal of the voltage controlled crystal oscillator is converted to a reference frequency to form a reference frequency signal. Since it is equipped with, it is possible to expand the choice of voltage controlled crystal oscillators by using a voltage controlled crystal oscillator whose oscillation frequency is easily available,
Furthermore, by providing a plurality of reference frequency converters instead of one, it is possible to simultaneously generate a plurality of reference frequency signals.

According to a seventh aspect of the present invention, in the invention according to any one of the first to sixth aspects, the metal case directly exposes the voltage-controlled crystal oscillator and a component whose performance is easily influenced by a change in ambient temperature. Since it is covered so that the GPS satellite radio wave is not received, there is an effect that the high stability of the reference frequency signal can be maintained for a long time. For example, by placing a reference device for setting a reference temperature and an operational amplifier used in a Peltier current controller in a metal case, the difference between the set temperature and the actual temperature can be reduced, and a highly stable reference frequency can be generated. Can be made.

According to an eighth aspect of the present invention, in the invention according to any one of the first to seventh aspects, the Peltier current controller sets the temperature in the metal case measured by the temperature sensor in the case to the voltage controlled crystal oscillator. Since the current flowing through the Peltier element is controlled in order to adjust the temperature to be adjusted when manufacturing the crystal unit to be configured, it is possible to oscillate the voltage-controlled crystal oscillator most stably, and Even if the temperature in the metal case deviates from the target set value, the deviation of the oscillation frequency can be minimized.

According to a ninth aspect of the present invention, in the invention according to any one of the first to eighth aspects, the voltage controlled crystal oscillator has temperature correction means for suppressing fluctuations in the oscillation frequency due to changes in the operating environment temperature. It is possible to obtain a comparatively high stability reference frequency from, and even if the target set value of the temperature inside the metal case deviates from the adjustment temperature during the manufacturing of the crystal unit, the oscillation frequency of the voltage controlled crystal oscillator is There is an effect that high stability can be maintained.

According to a tenth aspect of the invention, in any one of the first to ninth aspects, an ambient temperature sensor for measuring the ambient temperature of the metal case is provided, and the Peltier current controller controls the temperature inside the metal case. Since the current flowing through the Peltier element is controlled to bring the temperature based on the ambient temperature measured by the ambient temperature sensor, an appropriate current based on the measured ambient temperature is passed through the Peltier element to reduce current consumption. There is an effect that can be done.

According to an eleventh aspect of the present invention, in the tenth aspect of the invention, the Peltier current controller sets the temperature in the metal case to an average temperature of the ambient temperature measured by the ambient temperature sensor in a predetermined period. In addition, since the current flowing through the Peltier element is controlled, there is an effect that the current consumption in the Peltier element can be reduced.

According to a twelfth aspect of the present invention, in the tenth aspect of the present invention, the Peltier current controller causes the temperature in the metal case to flow to the Peltier element in order to approach the ambient temperature measured by the ambient temperature sensor. Since the current is controlled, the same effect as the eleventh aspect can be obtained.

The invention of claim 13 is the same as claim 11 or 1.
In the invention of 2, the satellite non-reception detector for detecting that the synchronization accuracy of the synchronization pulse signal formed by the GPS receiver or the stability of the intermediate frequency signal cannot be guaranteed and the GPS satellite radio wave is in the non-reception state is provided. When the satellite non-reception detector detects a non-reception state, the Peltier current controller holds the temperature in the metal case at the temperature before the detection of the non-reception state, so that the GPS satellite radio wave cannot be received. In this case, there is an effect that a high stability of the reference frequency can be maintained by keeping the temperature inside the metal case constant.

According to a fourteenth aspect of the present invention, in the thirteenth aspect of the present invention, the printed circuit board is provided with one printed circuit board on which components other than the GPS antenna are disposed, and the printed circuit board surrounds the metal case disposed on the circuit board. Since the holes are formed on the board surface of the substrate, it is possible to prevent heat conduction to the printed board, suppress the temperature fluctuation in the metal case, and reduce the current flowing to the Peltier element. is there.

According to a fifteenth aspect of the present invention, in the invention according to any one of the first to fourteenth aspects, since the metal case is provided with a heat insulating material on an outer wall or an inner wall, heat exchange between the inside of the metal case and the outside air is prevented, There is an effect that the temperature variation in the metal case can be suppressed and the current flowing through the Peltier element can be reduced.

According to a sixteenth aspect of the present invention, in any one of the first to fifteenth aspects, the target predetermined temperature in the metal case and the temperature in the metal case measured by the temperature sensor in the case are set. When the difference is larger than the predetermined difference, the Peltier current controller increases the current flowing through the Peltier element, so that there is an effect that it is possible to further shorten the time until the reference frequency is stabilized at the time of startup.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram showing a second embodiment of the present invention.

FIG. 3 is a circuit configuration diagram showing a third embodiment of the present invention.

FIG. 4 is a circuit configuration diagram showing a fourth embodiment of the present invention.

FIG. 5 is a circuit configuration diagram showing a fifth embodiment of the present invention.

FIG. 6 is a circuit configuration diagram showing a sixth embodiment of the present invention.

FIG. 7 is a circuit configuration diagram showing an eighth embodiment of the present invention.

FIG. 8 is a circuit configuration diagram showing a ninth embodiment of the present invention.

FIG. 9 is an external view showing a tenth embodiment of the present invention.

[Explanation of symbols]

1 GPS antenna 2 GPS receiver 3 Voltage controlled crystal oscillator 4 frequency converter 5 Phase comparator 6 Crystal voltage controller 7 Peltier element 8 Case temperature sensor 9 Peltier current controller 100 metal cases

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F002 AA13 AF01 CA04 CB02 CB16                       DA00 GA06                 5J062 AA08 AA13 CC07 DD12 EE01                 5J079 AA04 BA02 BA39 BA41 CA15                       KA06                 5J106 AA04 BB01 CC01 CC21 CC51                       EE02 GG01 HH01 KK13 LL08

Claims (16)

[Claims] 1. A GPS antenna for receiving a GPS satellite radio wave, a GPS receiver for forming an intermediate frequency signal and a synchronous pulse signal synchronized with Coordinated Universal Time based on the received GPS satellite radio wave, and oscillation by an applied voltage. A voltage controlled crystal oscillator whose oscillation frequency is controlled, a frequency converter which converts the oscillation signal into an intermediate frequency signal, a phase of the intermediate frequency signal formed by the GPS receiver, and the frequency converter. A phase comparator that compares the phase of a signal and outputs the comparison result, and a signal formed by the frequency converter based on the output signal of the phase comparator is synchronized with an intermediate frequency signal formed by the GPS receiver. The crystal voltage controller for controlling the voltage applied to the voltage controlled crystal oscillator and the voltage controlled crystal oscillator are covered so as not to come into direct contact with the outside air. A metal case, a Peltier element in close contact with the metal case, an in-case temperature sensor for measuring the temperature in the metal case, and an in-case temperature sensor for controlling the temperature in the metal case to a predetermined temperature. A Peltier current controller that controls a current flowing through the Peltier element based on the measurement result of 1., and outputs a reference frequency signal and the synchronization pulse signal according to the oscillation signal. . 2. A GPS antenna for receiving a GPS satellite radio wave, a GPS receiver for forming a synchronization pulse signal synchronized with the Coordinated Universal Time based on the received GPS satellite radio wave, and an oscillation frequency of an oscillation signal by an applied voltage. Controlled voltage controlled crystal oscillator, frequency converter for converting the oscillation signal into a signal having the same frequency as the synchronization pulse signal, phase of the synchronization pulse signal formed by the GPS receiver and signal formed by the frequency converter The phase of the frequency converter and the signal formed by the frequency converter based on the output signal of the phase comparator.
A crystal voltage controller for controlling a voltage applied to the voltage controlled crystal oscillator so as to be synchronized with a synchronization pulse signal formed by a PS receiver, and a metal case covering the voltage controlled crystal oscillator so as not to directly contact the outside air. A Peltier element in close contact with the metal case, a temperature sensor in the case for measuring the temperature in the metal case, and a measurement result of the temperature sensor in the case to bring the temperature in the metal case to a predetermined temperature. A Peltier current controller for controlling a current flowing through the Peltier element, and outputs a reference frequency signal and the synchronizing pulse signal according to the oscillation signal. 3. The frequency converter converts an oscillation signal of the voltage controlled crystal oscillator into a signal having the same frequency as the intermediate frequency signal and a signal having the same frequency as the synchronization pulse signal. The reference frequency generator described. 4. A satellite non-reception detector for detecting that the synchronization accuracy of a synchronization pulse signal formed by the GPS receiver or the stability of an intermediate frequency signal cannot be guaranteed and a GPS satellite radio wave is in a non-reception state. When the satellite unreceived detector does not detect the unreceived state, the synchronous pulse signal formed by the GPS receiver is output, and when the satellite unreceived detector detects the unreceived state, the frequency converter When the satellite non-reception detector detects a non-reception state, the crystal voltage controller is configured to output the same voltage as the synchronous pulse signal converted from the oscillation signal by the satellite non-reception controller. 4. The reference frequency generator according to claim 3, wherein the voltage applied to the controlled crystal oscillator is held at the voltage before detection of the unreceived state. 5. A satellite non-reception detector for detecting that the GPS satellite radio wave is in a non-reception state because the synchronization accuracy of the synchronization pulse signal formed by the GPS receiver or the stability of the intermediate frequency signal cannot be guaranteed. When the satellite non-reception detector detects a non-reception state by outputting a signal having the same frequency as the synchronizing pulse signal converted from the oscillation signal by the frequency converter, the crystal voltage controller controls the voltage control. 4. The reference frequency generator according to claim 3, wherein the voltage applied to the crystal oscillator is held at the voltage before detection of the unreceived state. 6. The reference according to claim 1, further comprising a reference frequency converter that converts an oscillation frequency of an oscillation signal of the voltage controlled crystal oscillator into a reference frequency to form a reference frequency signal. Frequency generator. 7. The metal case covers the voltage controlled crystal oscillator and parts whose performance is easily affected by changes in the outside temperature so as not to directly contact the outside air. The reference frequency generator described above. 8. The Peltier current controller sets the temperature in the metal case, which is measured by the temperature sensor in the case, to an adjustment temperature for adjusting the crystal oscillator that constitutes the voltage controlled crystal oscillator. The reference frequency generator according to any one of claims 1 to 7, further comprising: controlling a current flowing through the Peltier element. 9. The reference frequency generation device according to claim 1, wherein the voltage controlled crystal oscillator has a temperature correction unit that suppresses fluctuations in oscillation frequency due to changes in operating environment temperature. 10. An ambient temperature sensor for measuring an ambient temperature of the metal case, wherein the Peltier current controller sets the temperature in the metal case to a temperature based on the ambient temperature measured by the ambient temperature sensor. The reference frequency generator according to any one of claims 1 to 9, further comprising: controlling a current flowing through the Peltier element. 11. The Peltier current controller controls a current flowing through the Peltier element so that the temperature in the metal case becomes an average temperature of the ambient temperature measured by the ambient temperature sensor in a predetermined period. 11. The method according to claim 10,
The reference frequency generator described. 12. The Peltier current controller controls a current flowing through the Peltier element in order to bring the temperature in the metal case close to the ambient temperature measured by the ambient temperature sensor. The reference frequency generator described. 13. A satellite non-reception detector for detecting that the GPS satellite radio wave is in a non-reception state because the synchronization accuracy of the synchronization pulse signal formed by the GPS receiver or the stability of the intermediate frequency signal cannot be guaranteed. When the satellite non-reception detector detects a non-reception state, the Peltier current controller holds the temperature in the metal case at the temperature before the detection of the non-reception state. 1
2. The reference frequency generator described in 2. 14. A printed circuit board having a component other than the GPS antenna arranged therein, wherein the printed circuit board has holes formed in a surface of the circuit board around the metal case arranged on the circuit board. The reference frequency generator according to claim 13. 15. The reference frequency generator according to claim 1, wherein the metal case has a heat insulating material on an outer wall or an inner wall. 16. The Peltier current controller, when a difference between a target predetermined temperature in the metal case and a temperature in the metal case measured by the temperature sensor in the case is larger than a predetermined difference. 16. The reference frequency generator according to claim 1, wherein a current supplied to the Peltier element is increased.