JP2009005182A - Voltage controlled temperature compensated crystal oscillator, and temperature-oscillation frequency characteristics adjustment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain an oscillation frequency with high accuracy despite a change of an impressed voltage accompanying a temperature change in a VC-TCXO10 generating a nominal oscillation frequency upon impressing a reference voltage to a control voltage input terminal 22. <P>SOLUTION: A constant voltage circuit 11 generates a constant voltage supplied to a crystal oscillation circuit 14. A constant voltage output terminal 20 is a terminal which derives the constant voltage to the outside. At the time of an adjustment of a temperature-oscillation frequency characteristic of a VC-TCXO10 in a thermostatic oven 30, a connection line 38 is connected between the constant voltage output terminal 20 and a control voltage input terminal 22, and control data of a temperature compensation circuit 12 is set from a temperature compensation circuit adjustment terminal 21 so that the oscillation frequency may become a nominal value over the whole operating allowable temperature range. At the time of mounting the VC-TCXO10 on a mobile wireless device 45, a connection line 52 is connected between the constant voltage output terminal 20 and the control voltage input terminal 22. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a voltage-controlled temperature compensated crystal oscillator (VC-TCXO) mounted on a radio device, for example, and a temperature-oscillation frequency characteristic adjusting method thereof.

  Patent Document 1 discloses a communication device equipped with VC-TCXO (FIG. 1 of Patent Document 1). In the communication device, a voltage holding unit is interposed between the DAC (digital / analog converter) of the baseband unit and the VC-TCXO, and in the non-transmission period, the FET of the voltage holding unit is turned on to start from the DAC. Is stored in the capacitor of the voltage holding unit, and the FET of the voltage holding unit is turned off during the transmission period, thereby removing noise from the control voltage of the VC-TCXO during the transmission period. Thus, the modulation accuracy of the transmission wave is improved (paragraph 0020 of Patent Document 1).

  A conventional VC-TCXO 150 will be described with reference to FIGS. 12 is a configuration diagram of the VC-TCXO 150, FIG. 13 is a connection status diagram when the VC-TCXO 150 is adjusted before shipment from the manufacturer, and FIG. 14 is a diagram showing a connection status of the VC-TCXO 150 in the portable wireless device 45. Among the elements shown in FIGS. 12 to 14, the same elements as those shown in FIGS. 1 to 3 according to the present invention to be described later are designated by the same reference numerals as those shown in FIGS. Only the main points will be described.

  In FIG. 12, the constant voltage generated by the constant voltage circuit 11 is supplied to the temperature compensation circuit 12, the frequency control circuit 13, and the crystal oscillation circuit 14 that are mounted in the same VC-TCXO 150. The VC-TCXO 150 includes the temperature compensation circuit 12 to improve the stability of the oscillation frequency against temperature changes. The oscillation frequency of the oscillation signal output terminal 23 can be finely adjusted by the voltage applied to the control voltage input terminal 22. When this applied voltage is equal to a preset reference voltage, the oscillation frequency of the oscillation signal output terminal 23 is equal to its nominal frequency, and when the applied voltage is higher and lower than the reference voltage, the oscillation frequency is accordingly adjusted. The oscillation frequency of the oscillation signal output terminal 23 becomes higher and lower, respectively. There is also a VC-TCXO in which the relationship between the applied voltage level and the VC-TCXO frequency level is opposite to that of the VC-TCXO 150.

  In FIG. 13, the VC-TCXO 150 is housed in the thermostat 30 and the temperature-oscillation frequency characteristics are adjusted one by one. At the time of adjustment, the control voltage input terminal 22 is connected to a constant voltage source 160 outside the thermostat 30 via a connection line 161. The temperature in the thermostat 30 changes over the entire allowable temperature range of the VC-TCXO 150, and the VC-TCXO 150 has a constant voltage from the constant voltage source 160 outside the thermostat 30 to the control voltage input terminal 22 at each temperature. Control data of a storage device (not shown) of the temperature compensation circuit 12 is set by the jig 32 so that a nominal oscillation frequency is output to the temperature compensation circuit adjustment terminal 21 while a reference voltage is applied. Since the constant voltage source 160 is used with very high accuracy, the voltage applied to the control voltage input terminal 22 in the adjusting engine in the thermostat 30 is an extremely stable voltage.

The VC-TCXO 150 is mounted on a predetermined product in a manufacturer such as the portable wireless device 45 after shipment from the manufacturer. When the VC-TCXO 150 is mounted on, for example, the portable wireless device 45 (FIG. 14), the VC-TCXO 150 is applied with the control voltage from the constant voltage circuit 165 to the control voltage input terminal 22 thereof.
JP 2003-174380 A

  A temperature-compensated series regulator or shunt regulator is used for the constant voltage circuit 165 inside the portable radio 45 that generates the reference voltage applied to the control voltage input terminal 22. A portable type such as the portable radio 45 has restrictions on its size, current consumption, etc., and what is currently used is not as accurate as the constant voltage source 160 (FIG. 13), and the temperature of the voltage is stable. Even if the property is the best, the limit is about 30 ppm / ° C. Assuming that the temperature stability of the constant voltage circuit 165 is 30 ppm / ° C., problems of the VC-TCXO 150 will be described below.

The temperature deviation of the constant voltage source when the VC-TCXO 150 is used in the temperature range of 120 ° C. from −35 ° C. to + 85 ° C. is calculated as follows.
30 [ppm / ° C] × 120 [° C] = 3600 [ppm] (= 0.36%)

When the reference voltage of the control voltage input terminal 22 is set to 1.5V, the amount of change of the reference voltage is calculated as follows.
1.5 [V] × 3600 [ppm] = 5.4 [mV]

When the sensitivity to frequency of the control voltage input terminal 22 is 40 ppm / V (when the oscillation frequency changes by 40 ppm per 1 V of the control voltage), the amount of change in the oscillation frequency is calculated as follows.
40 [ppm / V] × 5.4 [mV] = 0.216 [ppm]

  That is, since the reference voltage applied to the control voltage input terminal 22 changes by 5.4 mV in temperature, the oscillation frequency of the oscillation signal output terminal 23 moves about 0.22 ppm.

  When adjusting by the manufacturer of the VC-TCXO 150, a constant reference voltage is used over the entire temperature range of -35 ° C to + 85 ° C. That is, the constant voltage source 160 (FIG. 13) itself applies a constant reference voltage to the control voltage input terminal 22 without any temperature change, regardless of the temperature change of the VC-TCXO 150 in the thermostat 30, and VC -Since the oscillation frequency of the TCXO 150 is adjusted, the oscillation frequency of the oscillation signal output terminal 23 becomes very stable. However, when the VC-TCXO 150 is actually mounted on the portable wireless device 45, the control voltage input terminal 22 is supplied with a control voltage from the constant voltage circuit 165, which is less accurate than the constant voltage source 160. In addition, unlike the constant voltage source 160 of FIG. 12, the constant voltage circuit 165 itself changes in temperature together with the VC-TCXO 150, so that the constant voltage circuit 165 goes to the control voltage input terminal 22 from the constant voltage circuit 165. The actual applied voltage is more unstable with respect to temperature than during adjustment in the thermostat 30. Therefore, the shift of the control voltage in the portable radio device 45 is sufficiently larger than the above-described about 0.22 ppm.

  Although Patent Document 1 mentions improvement in the accuracy of the oscillation frequency of the VC-TCXO by noise removal, it does not disclose a solution for improving the accuracy of the oscillation frequency with respect to fluctuations in the control voltage caused by a temperature change.

  An object of the present invention is to provide a voltage-controlled temperature-compensated crystal oscillator capable of improving the accuracy of an oscillation frequency with respect to fluctuations in a control voltage caused by a temperature change in a mounted state in an actual machine and a method for adjusting the temperature-oscillation frequency characteristics It is.

  According to the present invention, paying attention to the constant voltage circuit built in the voltage-controlled temperature-compensated crystal oscillator, the temperature-oscillation frequency characteristic of each voltage-controlled temperature-compensated crystal oscillator is adjusted, and each voltage-controlled temperature compensation is applied to the actual machine. The voltage-controlled temperature-compensated crystal oscillator is constructed so that the voltage generated by the constant voltage circuit can be used as the control voltage of the crystal-oscillated circuit of the voltage-controlled temperature-compensated crystal oscillator when the crystal oscillator is mounted. Specifically, a terminal for deriving the voltage related to the power supply voltage generated by the constant voltage circuit (including the power supply voltage itself) is added to the outside, or the voltage controlled temperature compensation crystal oscillator Or form wiring.

The voltage controlled temperature compensated crystal oscillator of the present invention includes the following.
Control voltage input terminal,
A crystal oscillation circuit that oscillates at a frequency based on a control voltage applied to the control voltage input terminal;
An oscillation signal output terminal for deriving the oscillation signal of the crystal oscillation circuit to the outside;
A constant voltage circuit for generating a constant voltage supply voltage to be supplied to the crystal oscillation circuit;
A temperature compensation circuit for compensating temperature with respect to an output of the crystal oscillation circuit; and a constant voltage output terminal for deriving a constant voltage related to a power supply voltage of the constant voltage circuit to the outside.

Another voltage controlled temperature compensated crystal oscillator of the present invention comprises:
A crystal oscillation circuit that oscillates at a frequency based on the control voltage,
An oscillation signal output terminal for deriving the oscillation signal of the crystal oscillation circuit to the outside;
A constant voltage circuit for generating a constant voltage supply voltage to be supplied to the crystal oscillation circuit;
A temperature compensation circuit that compensates the temperature of the output of the crystal oscillation circuit; and a control voltage supply circuit that supplies a constant voltage related to a power supply voltage of the constant voltage circuit to the crystal oscillation circuit as the control voltage.

The temperature-oscillation frequency characteristic adjusting method of the present invention includes the following steps.
The above-mentioned voltage controlled temperature compensated crystal oscillator is connected so that the input side reference voltage of the crystal oscillation circuit becomes a voltage related to the generated voltage of the constant voltage circuit, and is housed in a thermostatic chamber,
Changing the temperature in the thermostat over a predetermined range; and oscillation in the voltage controlled temperature compensated crystal oscillator so that the oscillation frequency of the crystal oscillator circuit is maintained at a nominal value at each temperature in the thermostat. Setting a frequency control factor;

  According to the present invention, in the adjustment of the temperature-oscillation frequency characteristic of the voltage controlled temperature compensated crystal oscillator, or in the actual equipment, the voltage related to the power supply voltage generated by the constant voltage circuit is used as the control voltage of the crystal oscillation circuit. Therefore, the change in the control voltage accompanying the change in temperature is reproduced in the same way as the change in the control voltage when adjusting the temperature-oscillation frequency characteristic when the actual machine is equipped. Therefore, the temperature-oscillation frequency characteristic when the actual device is mounted is the same as that when adjusting the temperature-oscillation frequency characteristic, and the accuracy of the oscillation frequency of the voltage controlled temperature compensation crystal oscillator can be improved.

  FIG. 1 is a block diagram of the VC-TCXO 10. The VC-TCXO 10 is manufactured in a chip form, and a constant voltage circuit 11, a temperature compensation circuit 12, a frequency control circuit 13, and a crystal oscillation circuit 14 are built therein. The VC-TCXO 10 includes a power supply input terminal 19, a constant voltage output terminal 20, a temperature compensation circuit adjustment terminal 21, a control voltage input terminal 22, an oscillation signal output terminal 23, and a ground terminal 24 for connection to the outside. .

  The constant voltage circuit 11 generates a predetermined constant voltage from the voltage supplied from the power input terminal 19, and distributes the constant voltage to the temperature compensation circuit 12, the frequency control circuit 13, the crystal oscillation circuit 14, and the constant voltage output terminal 20. To do.

  The temperature compensation circuit 12 includes, for example, a thermistor that detects temperature, a DAC (digital / analog converter) that adjusts the reverse voltage of the output-side variable capacitance diode, and a storage device that stores the adjustment value (eg, EPROM or FLHROM). And a microcomputer for controlling the output of the DAC according to the temperature based on the setting data of the storage device. The temperature compensation circuit 12 is configured to set data in the storage device based on a signal input from the temperature compensation circuit adjustment terminal 21 when adjusting a temperature-oscillation frequency characteristic of FIG.

  The frequency control circuit 13 applies a voltage corresponding to the voltage applied to the control voltage input terminal 22 to the output side variable capacitance diode as its reverse voltage. The variable capacitance diode on the output side of the temperature compensation circuit 12 and the variable capacitance diode on the output side of the frequency control circuit 13 are connected with their one ends facing each other to determine the input voltage of the crystal oscillation circuit 14. The crystal oscillation circuit 14 outputs an oscillation signal having a frequency related to the input voltage to the oscillation signal output terminal 23.

  FIG. 2 is a connection state diagram at the time of adjusting the temperature-oscillation frequency characteristic performed for each VC-TCXO 10 in the manufacturer of the VC-TCXO 10. The VC-TCXO 10 is housed in the thermostat 30 and during the adjustment of the temperature-oscillation frequency characteristics in the thermostat 30, the entire allowable temperature range of the VC-TCXO 10, for example, the entire temperature range of −35 ° C. to + 85 ° C. Subject to temperature changes. The constant voltage source 31, the jig 32, and the frequency counter 33 are provided outside the thermostat 30 and are connected to the power input terminal 19 of the VC-TCXO 10 in the thermostat 30 via the connection lines 37, 39, and 40, and the constant voltage output, respectively. The terminal 20 and the temperature compensation circuit adjustment terminal 21 are connected.

  The constant voltage source 31 supplies power to the power input terminal 19 of the VC-TCXO 10, and the frequency counter 33 measures the frequency of the oscillation signal output from the oscillation signal output terminal 23. The jig 32 is supplied to the temperature compensation circuit 12 via the temperature compensation circuit adjustment terminal 21 so that the frequency becomes a nominal value at each temperature in the change temperature range in the thermostatic chamber 30 in the temperature-oscillation frequency characteristic adjustment of the VC-TCXO 10. Data is sent and stored in the storage device of the temperature compensation circuit 12.

  FIG. 3 is a connection diagram when the VC-TCXO 10 is installed in the portable radio device 45. The portable radio device 45 is equipped with a housing 46 and an antenna 47. The VC-TCXO 10 is disposed in the housing 46 together with the battery 50, the constant voltage circuit 51, and the local oscillation circuit 53. The power input terminal 19 is supplied with power from the battery 50 via the constant voltage circuit 51. The constant voltage output terminal 20 and the control voltage input terminal 22 are connected to each other by a connection line 52. The oscillation signal output terminal 23 is connected to the local oscillation circuit 53 and supplies an oscillation signal to the local oscillation circuit 53. The ground terminal 24 is connected to a ground 54 in the housing 46.

  In the portable radio device 45, the output voltage of the constant voltage circuit 11 of the VC-TCXO 10 changes slightly as the temperature in the portable radio device 45 changes. The generated voltage of the temperature compensation circuit 12 is supplied not only to the temperature compensation circuit 12, the frequency control circuit 13 and the crystal oscillation circuit 14 in the VC-TCXO 10, but also to the control voltage input terminal 22 via the connection line 52. As described with reference to FIG. 2, this is the same situation as when the VC-TCXO 10 is housed in the thermostatic chamber 30 at the shipping manufacturer and the temperature-oscillation frequency characteristics are adjusted. Therefore, even if the voltage applied to the control voltage input terminal 22 changes as the temperature in the housing 46 changes, the frequency of the oscillation signal at the oscillation signal output terminal 23 is the temperature-oscillation frequency at the manufacturer that shipped the VC-TCXO 10. As with the characteristic adjustment, the nominal value can be maintained.

  FIG. 4 is a circuit diagram to cope with the case where the voltage divider 61 is externally attached to the VC-TCXO 60 when the generated voltage of the constant voltage circuit 11 and the reference voltage of the control voltage input terminal 22 are different. The reference voltage at the control voltage input terminal 22 is defined as the voltage at the control voltage input terminal 22 when a nominal oscillation frequency is output to the oscillation signal output terminal 23 at each temperature. Among the elements of the VC-TCXO 60, the same elements as those of the VC-TCXO 10 of FIG. 1 are designated by the reference numerals attached to the elements of the VC-TCXO 10 and their description is omitted.

  The voltage divider 61 is provided outside the VC-TCXO 60, and both ends thereof are connected to the constant voltage output terminal 20 and the ground, respectively, and the voltage dividing terminal is connected to the control voltage input terminal 22. The voltage divider 61 externally attached to the VC-TCXO 60 is used both for adjusting the temperature-oscillation frequency characteristics of the VC-TCXO 60 in the thermostat 30 and for mounting the VC-TCXO 60 in the portable radio 45. Used in place of line 38 (FIG. 2) and connecting line 52 (FIG. 3). Actually, the voltage divider 61 used when adjusting the temperature-oscillation frequency characteristics of the VC-TCXO 60 in the thermostat 30 is different from the voltage divider 61 used when mounting the VC-TCXO 60 on the portable radio 45. The former and latter voltage dividers 61 are distinguished from each other as voltage dividers 61a and 61b for convenience of explanation.

  In the temperature-oscillation frequency characteristic adjustment, the voltage divider 61a is previously connected to the control voltage input terminal 22 at a predetermined temperature at which the voltage of the voltage dividing terminal is appropriately selected within the range of -35 ° C to + 85 ° C. The voltage dividing resistor is set so as to be the reference voltage. And the voltage divider 61a is connected with VC-TCXO60 like the voltage divider 61 of FIG. 4, and is accommodated in the thermostat 30. FIG. Thereafter, the temperature in the thermostatic chamber 30 is changed over the entire allowable use temperature range of the VC-TCXO 60. In the VC-TCXO 60, the data in the storage device of the temperature compensation circuit 12 is set by the jig 32 so that the oscillation frequency of the oscillation signal output terminal 23 becomes a nominal value at each temperature.

  In the portable wireless device 45, the voltage divider 61b is connected to the VC-TCXO 60 like the voltage divider 61 in FIG. 4 and the voltage dividing point is adjusted so that the reference voltage is generated at the control voltage input terminal 22. The Note that the temperatures of the VC-TCXO 60 and the voltage divider 61 b at this time are both the same, and are included in the temperature change range received by the VC-TCXO 60 in the thermostatic chamber 30. Therefore, even if the temperature in the housing 46 changes thereafter, it is the temperature adjusted so that the VC-TCXO 60 outputs the nominal oscillation frequency in the thermostatic bath 30. As a result, the VC-TCXO 60 generates the nominal oscillation frequency at the oscillation signal output terminal 23 in the portable radio device 45 regardless of the temperature change.

  FIG. 5 is a circuit diagram of the VC-TCXO 65 to cope with the case where the voltage divider 66 is incorporated when the generated voltage of the constant voltage circuit 11 and the reference voltage of the control voltage input terminal 22 are different. Among the elements of the VC-TCXO 65, the same elements as the elements of the VC-TCXO 60 in FIG. 4 are designated by the reference numerals attached to the elements of the VC-TCXO 60, and their description is omitted.

  The VC-TCXO 65 includes a voltage divider 66 and includes a constant voltage output terminal 67. The voltage divider 66 plays the same role as the voltage divider 61 of FIG. 4, and is connected to the output terminal of the constant voltage circuit 11 and the ground at both ends, and the voltage dividing point is a constant voltage output terminal. 67. The voltage dividing point of the voltage divider 66 generates the same voltage as the voltage dividing point of the voltage divider 61.

  The VC-TCXO 65 has a connection line 38 (FIG. 2) connected between the constant voltage output terminal 67 and the control voltage input terminal 22 in the temperature-oscillation frequency characteristic adjustment in the thermostatic chamber 30, and is connected to the portable radio device 45. At the time of mounting, the connection line 52 (FIG. 3) is connected between the constant voltage output terminal 67 and the control voltage input terminal 22. In the VC-TCXO 60 of FIG. 4, the voltage dividers 61 a and 61 b are necessary when adjusting the temperature-oscillation frequency characteristics in the thermostatic chamber 30 and mounting the portable radio device 45. In the VC-TCXO 65, The pressure devices 61a and 61b can be omitted. In addition, the connection lines 38 and 52 have a smaller product variation in resistance value than the voltage dividers 61a and 61b.

  In the VC-TCXO 65, if the voltage dividing point of the voltage divider 66 is connected to the input side of the frequency control circuit 13 by the internal wiring of the VC-TCXO 65, the constant voltage output terminal 67 can be omitted. An example is VC-TCXO 88 in FIG. 8 described later. Further, in the VC-TCXO 88 of FIG. 8, the control voltage input terminal 22 remains, but when the voltage dividing point of the voltage divider 66 is connected to the input side of the frequency control circuit 13 by the internal wiring of the VC-TCXO 65, The control voltage input terminal 22 may be omitted.

  FIG. 6 is a circuit diagram of the VC-TCXO 72 in which the oscillation signal output terminal 23 also serves as a terminal for deriving the constant voltage of the constant voltage circuit 11. Among the elements of the VC-TCXO 72, the same elements as those of the VC-TCXO 10 in FIG. 1 are designated by the reference numerals attached to the elements of the VC-TCXO 10, and their description is omitted.

  In the VC-TCXO 72, the constant voltage output terminal 20 (FIG. 1) of the VC-TCXO 10 is omitted. The capacitor 73 is interposed between the output terminal of the crystal oscillation circuit 14 and the oscillation signal output terminal 23. The resistor 74 is interposed between the output terminal of the constant voltage circuit 11 and the oscillation signal output terminal 23. The output of the constant voltage circuit 11 is a direct current, whereas the output of the crystal oscillation circuit 14 is an alternating current. The capacitor 73 prevents the output terminal of the crystal oscillation circuit 14 from being affected by the DC generated voltage of the constant voltage circuit 11.

  In the VC-TCXO 72 in the portable radio device 45, the oscillation signal output terminal 23 is connected to the input side of the local oscillation circuit 53 via the capacitor 78. The oscillation signal output terminal 23 is also connected to the control voltage input terminal 22 via an LPF (low-pass filter) 79. The capacitor 78 allows the oscillation signal generated by the crystal oscillation circuit 14 to pass while preventing the DC constant voltage of the constant voltage circuit 11 from being sent to the local oscillation circuit 53. The LPF 79 prevents the oscillation signal generated by the crystal oscillation circuit 14 from being transmitted to the control voltage input terminal 22.

  When the temperature-oscillation frequency characteristic of the VC-TCXO 72 is adjusted in the thermostatic chamber 30, the power source input terminal 19 and the temperature compensation circuit adjustment terminal 21 are connected to the constant voltage source 31 and the jig 32 of FIG. A frequency counter 33 is connected to the voltage input terminal 22 and the oscillation signal output terminal 23 in place of the local oscillation circuit 53 while leaving the capacitor 78 and the LPF 79 of FIG. The capacitor 78 and LPF 79 used when the VC-TCXO 72 is mounted on the portable radio 45 and the capacitor 78 and LPF 79 used when adjusting the VC-TCXO 72 in the thermostat 30 are not the same, but the portable radio At the time of manufacture of the machine 45, the VC-TCXO 72, the capacitor 78 and the LPF 79 are set at predetermined values in the capacitor 78 and the LPF 79 so that the oscillation frequency on the input side of the local oscillation circuit 53 becomes a nominal frequency at a certain temperature under the same temperature environment. If the value of the element is adjusted, the element value at the time of adjusting the temperature-oscillation frequency characteristic in the thermostatic chamber 30 is reproduced at the temperature. Therefore, even if the temperature changes to another temperature, the oscillation signal output terminal The frequency of the 23 oscillating signals is maintained at a nominal value.

  FIG. 7 is a circuit diagram of the VC-TCXO 82 in which the temperature compensation circuit adjustment terminal 21 also serves as a terminal for deriving the constant voltage of the constant voltage circuit 11. Among the elements of the VC-TCXO 82, the same elements as those of the VC-TCXO 72 of FIG. 6 are designated by the reference numerals attached to the elements of the VC-TCXO 72, and the description thereof is omitted. In the VC-TCXO 82, a resistor 83 is added in the VC-TCXO 82 in place of the capacitor 73 and the resistor 74 of the VC-TCXO 72.

  The resistor 83 is interposed between the output terminal of the constant voltage circuit 11 and one of the temperature compensation circuit adjustment terminals 21. The output impedance of the jig 32 (FIG. 2) is sufficiently lower than the resistance value of the resistor 83. When adjusting the VC-TCXO 82 in the thermostat 30 and when mounting the VC-TCXO 82 on the portable wireless device 45, one temperature compensation circuit adjustment terminal 21 for outputting the rated voltage of the constant voltage circuit 11 and a control voltage input terminal 22 is connected to a connection line such as the connection line 52 (FIG. 3) or a voltage divider such as the voltage divider 61 (FIG. 4). That is, in the case of a connection line, the connection line connects the constant voltage output temperature compensation circuit adjustment terminal 21 and the control voltage input terminal 22. In the case of a voltage divider, both ends of the voltage divider are connected to the constant voltage output temperature compensation circuit adjustment terminal 21 and the ground, and the voltage dividing point is connected to the control voltage input terminal 22.

  FIG. 8 shows a VC-TCXO 88 used for signal generation such as FM and its connection diagram. Among the elements of the VC-TCXO 88, the same elements as those of the VC-TCXO 65 of FIG. 5 are designated by the reference numerals attached to the elements of the VC-TCXO 65, and the description thereof is omitted.

  In the VC-TCXO 65, the voltage dividing point of the voltage divider 66 is connected to the constant voltage output terminal 67, whereas in the VC-TCXO 88, the constant voltage output terminal 67 is omitted, and the voltage dividing point of the voltage divider 66 is The VC-TCXO 88 is connected to the control voltage input terminal 22 by an internal wiring. The modulation signal generation circuit 91 generates a modulation signal (baseband signal) such as FM or FSK, and is connected to the control voltage input terminal 22 via the capacitor 92. The capacitor 92 prevents the direct current component from the modulation signal generation circuit 91 from being sent to the control voltage input terminal 22.

  The VC-TCXO 88 is separated from the modulation signal generation circuit 91 and the capacitor 92 and accommodated in the thermostatic chamber 30 when adjusting the temperature-oscillation frequency characteristics before shipment from the manufacturer. In this case, a constant voltage source 31, a jig 32, and a frequency counter 33 are connected to the power input terminal 19, the temperature compensation circuit adjustment terminal 21, and the oscillation signal output terminal 23, respectively. Also, nothing is connected to the control voltage input terminal 22. The VC-TCXO 88 is connected to a modulation signal generation circuit 91 and a capacitor 92 as shown in FIG. 8 when mounted on the portable wireless device 45. In the VC-TCXO 88 in the housing 46 of the portable radio 45, the DC voltage applied to the control voltage input terminal 22 is adjusted when the temperature-oscillation frequency characteristics in the thermostatic chamber 30 are adjusted with respect to the temperature change in the housing 46. It changes in the same way as the corresponding temperature change in. Therefore, the VC-TCXO 88 generates an oscillation frequency accurately associated with the modulation signal by superimposing the modulation signal from the modulation signal generation circuit 91 on the control voltage input terminal 22 to eliminate the influence of temperature. To do.

  FIG. 9 is a block diagram of the voltage controlled temperature compensated crystal oscillator 100. The voltage control temperature compensation crystal oscillator 100 includes at least a control voltage input terminal 101, a crystal oscillation circuit 102, an oscillation signal output terminal 103, a constant voltage circuit 104, a temperature compensation circuit 105, and a constant voltage output terminal 106. Specific examples of the voltage controlled temperature compensating crystal oscillator 100 are the VC-TCXO 10 (FIG. 1), 60 (FIG. 4), 65 (FIG. 5), 72 (FIG. 6), and 82 (FIG. 7).

  The crystal oscillation circuit 102 oscillates at a frequency based on the control voltage applied to the control voltage input terminal 101. The oscillation signal output terminal 103 leads the oscillation signal of the crystal oscillation circuit 102 to the outside. The constant voltage circuit 104 generates a constant power supply voltage to be supplied to the crystal oscillation circuit 102. The temperature compensation circuit 105 performs temperature compensation on the output of the crystal oscillation circuit 102. The constant voltage output terminal 106 derives a constant voltage related to the power supply voltage of the constant voltage circuit 104 to the outside.

  The control voltage input terminal 101, the crystal oscillation circuit 102, the oscillation signal output terminal 103, the constant voltage circuit 104, the temperature compensation circuit 105, and the constant voltage output terminal 106 are, for example, the control voltage input terminal 22 and the crystal oscillation circuit in the VC-TCXO 10, respectively. 14, the oscillation signal output terminal 23, the constant voltage circuit 11, the temperature compensation circuit 12, and the constant voltage output terminal 20. In the constant voltage output terminal 106, the constant voltage related to the power supply voltage of the constant voltage circuit 104 includes the power supply voltage itself of the constant voltage circuit 104.

  It is necessary to apply a reference voltage to the control voltage input terminal 101 when adjusting the temperature-oscillation frequency characteristics of the voltage controlled temperature compensated crystal oscillator 100 and when mounting the voltage controlled temperature compensated crystal oscillator 100 on an actual device. As a result of the constant voltage output terminal 106 being provided in the voltage controlled temperature compensation crystal oscillator 100, the constant voltage related to the power supply voltage of the constant voltage circuit 104 can be used as the reference voltage in common during adjustment and mounting. Therefore, it is possible to suppress the fluctuation of the oscillation frequency with respect to the temperature change at the time of mounting and improve the accuracy of the oscillation frequency.

  In one example, the voltage controlled temperature compensation crystal oscillator 100 includes a voltage dividing circuit 115. The voltage dividing circuit 115 generates the divided voltage of the power supply voltage of the constant voltage circuit 104 as a constant voltage related to the power supply voltage of the constant voltage circuit 104. A specific example of the voltage dividing circuit 115 is a voltage divider 66 (FIG. 5). Even when the constant voltage generated by the constant voltage circuit 104 is different from the reference voltage of the control voltage input terminal 101 by the voltage dividing circuit 115, it is possible to appropriately cope with it.

  The constant voltage output terminal 106 can also serve as the oscillation signal output terminal 103. A specific example of the constant voltage output terminal 106 also serving as the oscillation signal output terminal 103 is the oscillation signal output terminal 23 of the VC-TCXO 72 (FIG. 6). The temperature compensation circuit adjustment terminal 116 may also serve as the constant voltage output terminal 106. The temperature compensation circuit adjustment terminal 116 is for supplying a setting signal for setting temperature control data to the temperature compensation circuit 105 from the outside. A specific example of the temperature compensation circuit adjustment terminal 116 that also serves as the oscillation signal output terminal 103 is the temperature compensation circuit adjustment terminal 21 of the VC-TCXO 82 (FIG. 7). The voltage-controlled temperature compensation crystal oscillator 100 may include both the oscillation signal output terminal 103 that also serves as the constant voltage output terminal 106 and the temperature compensation circuit adjustment terminal 116 that also serves as the constant voltage output terminal 106.

  FIG. 10 is a block diagram of the voltage controlled temperature compensated crystal oscillator 120. Among the elements of the voltage-controlled temperature-compensated crystal oscillator 120, the same elements as those of the voltage-controlled temperature-compensated crystal oscillator 100 of FIG. The differences are described below. The crystal oscillation circuit 102 oscillates at a frequency based on the control voltage. The control voltage supply circuit 121 supplies a constant voltage related to the power supply voltage of the constant voltage circuit 104 to the crystal oscillation circuit 102 as a control voltage.

  A specific example of the voltage controlled temperature compensating crystal oscillator 120 is a VC-TCXO 88 (FIG. 8). In the voltage controlled temperature compensated crystal oscillator 100 (FIG. 9), the constant voltage output terminal 106 is required, but in the voltage controlled temperature compensated crystal oscillator 120, the constant voltage output terminal 106 can be omitted. Further, when the temperature-oscillation frequency characteristic adjusting method 130 described later is performed on the voltage-controlled temperature-compensated crystal oscillator 120, it is necessary in the voltage-controlled temperature-compensated crystal oscillator 100 when adjusting the temperature-oscillation frequency characteristic or mounting. The connection circuit between the control voltage input terminal 101 and the constant voltage output terminal 106 can be omitted.

  In the voltage controlled temperature compensated crystal oscillator 120, the control voltage supply circuit 121 can be a voltage dividing circuit that generates the divided voltage of the power supply voltage of the constant voltage circuit as the control voltage.

  FIG. 11 is a flowchart of the temperature-oscillation frequency characteristic adjusting method 130. The temperature-oscillation frequency characteristic adjustment method 130 is applied to the voltage controlled temperature compensated crystal oscillators 100 and 120.

  In S131, connection is performed so that the input-side reference voltage of the crystal oscillation circuit 102 becomes a voltage related to the generated voltage of the constant voltage circuit, and the crystal oscillation circuit 102 is accommodated in the thermostatic chamber. Regarding the connection, the voltage controlled temperature compensated crystal oscillator 100 is like the connection line 38 in FIG. 2, but the voltage controlled temperature compensated crystal oscillator 120 is connected to the inside thereof. No external connection is required.

  In S132, the temperature in the thermostat is changed over a predetermined range. In S133, the oscillation frequency control factor in the voltage controlled temperature compensation crystal oscillators 100 and 120 is set so that the oscillation frequency of the crystal oscillation circuit 102 is maintained at a nominal value at each temperature in the thermostat.

  In the VC-TCXO 10 as a specific example of the voltage controlled temperature compensation crystal oscillator 100, when adjusting the temperature-oscillation frequency characteristics in the thermostat 30, data is sent from the jig 32 to the temperature compensation circuit 12 via the temperature compensation circuit adjustment terminal 21. Although the temperature control data in the storage device of the temperature compensation circuit 12 is set, the oscillation frequency control factor in the voltage controlled temperature compensation crystal oscillators 100 and 120 may be an element value other than the temperature compensation circuit 105. To do.

  This specification discloses various inventions. In these inventions, in the best mode of the invention in the present specification, one or a plurality of elements exhibiting independent actions and effects are extracted, or one or a plurality of elements are changed within the obvious range In addition, a combination of one or a plurality of elements is interchanged between modes of the invention within the obvious range.

It is a block diagram of VC-TCXO. It is a connection condition figure at the time of the temperature-oscillation frequency characteristic adjustment performed about each VC-TCXO in the manufacturer of VC-TCXO. It is a connection diagram when VC-TCXO is equipped in a portable radio. FIG. 5 is a circuit diagram for dealing with a case where a voltage divider is externally attached to VC-TCXO when a generated voltage of a constant voltage circuit is different from a reference voltage of a control voltage input terminal. It is a circuit diagram of VC-TCXO which copes with the case where the generated voltage of the constant voltage circuit is different from the reference voltage of the control voltage input terminal by incorporating a voltage divider. It is a circuit diagram of VC-TCXO in which an oscillation signal output terminal also serves as a terminal for deriving a constant voltage of a constant voltage circuit. It is a circuit diagram of VC-TCXO in which a temperature compensation circuit adjustment terminal also serves as a terminal for deriving a constant voltage of a constant voltage circuit.

It is a figure which shows VC-TCXO currently utilized for signal generation, such as FM, and its connection diagram. It is a block diagram of a voltage control temperature compensation crystal oscillator. It is a block diagram of another voltage control temperature compensation crystal oscillator. It is a flowchart of the temperature-oscillation frequency characteristic adjustment method. It is a block diagram of conventional VC-TCXO. It is a connection condition figure at the time of adjustment of the conventional VC-TCXO before maker shipment. It is a figure which shows the connection state of the conventional VC-TCXO in a portable radio | wireless machine.

Explanation of symbols

100: Voltage control temperature compensation crystal oscillator 101: Control voltage input terminal 102: Crystal oscillation circuit 103: Oscillation signal output terminal 104: Constant voltage circuit 105: Temperature compensation circuit 106: Constant voltage output terminal 115: Voltage divider circuit 116: Temperature compensation circuit adjustment terminal 120: Voltage control temperature compensation crystal oscillator 121: Control voltage supply circuit 130: Temperature-oscillation frequency characteristic adjustment method

Claims (7)

Control voltage input terminal,
A crystal oscillation circuit that oscillates at a frequency based on a control voltage applied to the control voltage input terminal;
An oscillation signal output terminal for deriving the oscillation signal of the crystal oscillation circuit to the outside;
A constant voltage circuit for generating a constant voltage supply voltage to be supplied to the crystal oscillation circuit;
A temperature compensation circuit for temperature compensation of the output of the crystal oscillation circuit, and a constant voltage output terminal for deriving a constant voltage related to a power supply voltage of the constant voltage circuit to the outside,
A voltage-controlled temperature-compensated crystal oscillator comprising: A voltage dividing circuit for generating a divided voltage of the power supply voltage of the constant voltage circuit as a constant voltage related to the power supply voltage of the constant voltage circuit;
The voltage controlled temperature compensated crystal oscillator according to claim 1, further comprising:   3. The voltage controlled temperature compensated crystal oscillator according to claim 1, wherein the oscillation signal output terminal also serves as the constant voltage output terminal.   The temperature compensation circuit adjustment terminal supplied from outside with a setting signal for setting temperature control data to the temperature compensation circuit also serves as the constant voltage output terminal. The voltage-controlled temperature-compensated crystal oscillator described. A crystal oscillation circuit that oscillates at a frequency based on the control voltage,
An oscillation signal output terminal for deriving the oscillation signal of the crystal oscillation circuit to the outside;
A constant voltage circuit for generating a constant voltage supply voltage to be supplied to the crystal oscillation circuit;
A temperature compensation circuit that compensates the temperature of the output of the crystal oscillation circuit, and a control voltage supply circuit that supplies, as the control voltage, a constant voltage related to a power supply voltage of the constant voltage circuit to the crystal oscillation circuit;
A voltage-controlled temperature-compensated crystal oscillator comprising:   6. The voltage-controlled temperature-compensated crystal oscillator according to claim 5, wherein the control voltage supply circuit is a voltage dividing circuit that generates a divided voltage of a power supply voltage of a constant voltage circuit as the control voltage. A temperature controlled temperature controlled crystal oscillator according to any one of claims 1 to 6, wherein a connection is made so that an input side reference voltage of the crystal oscillation circuit becomes a voltage related to a generated voltage of the constant voltage circuit, Step to house,
Changing the temperature in the thermostat over a predetermined range; and oscillation in the voltage controlled temperature compensated crystal oscillator so that the oscillation frequency of the crystal oscillator circuit is maintained at a nominal value at each temperature in the thermostat. Setting a frequency control factor;
A temperature-oscillation frequency characteristic adjustment method comprising:

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