JP2013156149A - Radio wave correction clock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio wave correction clock capable of obtaining high receiving sensitivity without depending upon a frequency of a standard radio wave received.SOLUTION: A radio wave correction clock 1 can receive a plurality of standard radio waves having carrier frequencies different from one another and corrects time of a time counter 43 on the basis of any one of the plurality of standard radio waves. The radio wave correction clock 1 comprises: a controller 45 for setting a carrier frequency of a standard radio wave received out of the plurality of standard radio waves; a tuned circuit 31 that receives the standard radio wave of the set carrier frequency and acquires a reception signal; a frequency conversion section 34 for converting the acquired reception signal into a processing signal of a predetermined intermediate frequency; and a BPF 35 for extracting a signal of a frequency component having a predetermined bandwidth from the processing signal. The higher the carrier frequency is, the more the BPF 35 widens the bandwidth.

Description

  The present invention relates to a radio-controlled timepiece that receives a standard radio wave having time information and corrects the time based on the received standard radio wave.

A radio-controlled timepiece that receives a standard radio wave including time information and corrects the time is known.
The standard radio wave received by the radio-controlled timepiece has a different frequency depending on the region. For example, in Japan, there is a standard radio wave with a frequency of 40 kHz transmitted from the Fukushima station of a long wave standard radio wave facility and a standard radio wave with a frequency of 60 kHz transmitted from the Kyushu station. In addition, standard radio waves with other frequencies are used outside of Japan. For example, standard radio waves with a frequency of 77.5 kHz are used in Germany.

Since these standard radio waves have different frequency wavelength bands, when extracting the received signal envelope from the standard radio wave using a filter in a radio-controlled watch, it is necessary to prepare a filter with a bandwidth corresponding to each frequency. There is a problem that the watch becomes larger and more complicated.
On the other hand, a radio-controlled timepiece has been proposed in which the frequency of a standard radio wave is converted to a predetermined fixed frequency and the envelope of the received signal is extracted with a single filter (see, for example, Patent Document 1).

  The radio-controlled timepiece of Patent Document 1 includes a superheterodyne type radio wave receiver, and in a frequency conversion circuit, synthesizes the frequency of the standard radio wave input from the antenna and the local oscillation frequency input from the local oscillation circuit, Conversion to a predetermined intermediate frequency. A signal necessary for time correction from the intermediate frequency signal converted by the frequency conversion circuit using a bandpass filter that passes a predetermined range of frequencies centered on the intermediate frequency and cuts off frequency components outside the range. Extract ingredients.

JP 2004-80073 A

By the way, when a superheterodyne frequency conversion circuit is used, a signal of the local oscillation frequency input from the local oscillation circuit is easily affected by a temperature change, thereby causing a shift in the intermediate frequency converted by the frequency conversion circuit. There is a case.
FIG. 6 is a diagram showing the relationship between the amount of deviation (ΔF) of the converted frequency and the temperature when frequency conversion is performed using a superheterodyne frequency conversion circuit.
As shown in FIG. 6, the frequency deviation amount ΔF converted by the frequency conversion circuit becomes a minimum value (0) at a predetermined reference temperature T ₀ (for example, 25 degrees), and the temperature difference from the reference temperature is It grows as it grows. In particular, a standard radio wave with a high frequency has a larger frequency deviation amount ΔF during frequency conversion due to a temperature change than a standard radio wave with a low frequency.
For this reason, the radio-controlled timepiece as described in Patent Document 1 has a problem that the reception sensitivity is lower when receiving a high-frequency standard radio wave than when receiving a low-frequency standard radio wave. .

  An object of the present invention is to provide a radio-controlled timepiece capable of obtaining high reception sensitivity regardless of the frequency of a standard radio wave to be received.

  The radio-controlled timepiece of the present invention is a radio-controlled timepiece that can receive a plurality of standard radio waves having different carrier frequencies and corrects the time of the internal clock based on any one of the plurality of standard radio waves. Among the plurality of standard radio waves, a reception frequency setting unit for setting a carrier frequency of the standard radio wave to be received, the standard radio wave of the carrier frequency set by the reception frequency setting unit is received, and the carrier frequency is defined as a reception frequency. A received signal acquisition unit for acquiring a received signal, a frequency converter for converting the acquired received signal into a processing signal of a predetermined intermediate frequency, and a signal of a frequency component of a predetermined bandwidth from the processing signal And a filter unit that extracts the frequency band, and the filter unit increases the bandwidth as the carrier frequency set by the reception frequency setting unit increases.

In the present invention, when the standard radio wave of the carrier frequency set by the reception frequency setting unit is received by the reception signal acquisition unit and the reception signal is acquired, the frequency conversion unit converts the acquired reception signal to a predetermined intermediate frequency. Convert to processing signal. At this time, as described above, the intermediate frequency of the processing signal converted by the frequency conversion unit may be shifted with respect to the target frequency due to the influence of temperature. The frequency increases as the frequency (carrier frequency of standard radio waves) increases.
On the other hand, the filter unit of the present invention expands the bandwidth of the frequency component to be passed as the carrier frequency increases based on the carrier frequency set by the reception frequency setting unit. For example, JJY, which is a standard radio wave used in Japan, includes a standard radio wave of 40 kHz and a standard radio wave of 60 kHz, and time codes having the same data structure are embedded in each. In this case, when the filter unit of the present invention receives the standard radio wave of 60 kHz, the bandwidth of the frequency component to be passed is wider than when the standard radio wave of 40 kHz is received.
As a result, even when the amount of deviation of the intermediate frequency of the processing signal increases, the frequency component including the signal necessary for time correction is not blocked, and reception sensitivity can be improved.
On the other hand, in the present invention, when the reception frequency of the received signal (the carrier frequency of the standard radio wave) is low, the bandwidth of the filter unit is narrowed. In other words, when the reception frequency of the received signal is low, the amount of deviation of the intermediate frequency due to temperature changes is small, so even if the bandwidth of the filter section is narrow, the frequency component containing the signal necessary for time correction is passed. Is possible. In this case, noise components and the like can be satisfactorily blocked by the filter unit, and reception sensitivity can be improved.

  A radio-controlled timepiece according to the present invention includes a reference signal generation unit that generates a reference signal having a predetermined reference frequency, and a local oscillation signal generation unit that generates a local oscillation signal having a predetermined local oscillation frequency from the reference signal. The frequency converter preferably synthesizes the received signal and the local oscillation signal to convert the received signal into the processing signal.

In the present invention, the local oscillation signal generation unit generates a local oscillation signal of a predetermined local oscillation frequency based on the reference signal of the reference frequency output from the reference signal generation unit, and the frequency conversion unit generates the generated local By combining the oscillation signal and the reception signal, the reception signal is converted into a processing signal. That is, in the present invention, frequency conversion using the superheterodyne method is performed. By using such a superheterodyne system, even when standard radio waves having different carrier frequencies are received, it is possible to align with one intermediate frequency, and a signal can be extracted by one filter unit. Therefore, it is possible to simplify the configuration of the radio-controlled timepiece.
Examples of the reference signal generator include an oscillation circuit using a crystal resonator (reference frequency: 32.768 kHz), and the oscillation circuit using a crystal resonator is particularly small and lightweight. Therefore, it is suitable for a reference signal generation unit incorporated in a wristwatch or the like. On the other hand, in such a reference signal generator, the oscillation frequency may change due to the influence of temperature. In this case, the local oscillation frequency of the local oscillation signal generated based on the reference signal also changes, and the reference signal reference The greater the difference between the frequency and the local oscillation frequency (the greater the frequency change rate), the greater the amount of change. As a result, especially in the upper heterodyne system, the higher the carrier frequency of the standard radio wave, the greater the amount of deviation of the intermediate frequency of the processing signal. However, in the present invention, even when such a shift occurs, as described above, it is possible to suppress a decrease in reception sensitivity by widening the bandwidth of the filter unit.

  The radio-controlled timepiece according to the present invention includes a temperature sensor that detects a temperature, and the filter unit is configured to detect the band based on a temperature detected by the temperature sensor and a carrier frequency set by the reception frequency setting unit. It is preferable to change the width.

In the present invention, the filter unit changes the bandwidth based on the temperature detected by the temperature sensor and the carrier frequency of the received standard radio wave.
That is, as shown in FIG. 6, the amount of deviation of the intermediate frequency converted by the frequency converter becomes minimum at a predetermined reference temperature, and increases as the temperature difference from the reference temperature increases. Accordingly, even when a standard radio wave having a high carrier frequency is received as long as it is near the reference temperature, the amount of deviation of the intermediate frequency converted by the frequency converter is small. Conversely, even when a standard radio wave with a low carrier frequency is received, if the temperature difference from the reference temperature is large, the amount of deviation of the intermediate frequency converted by the frequency converter becomes large.
In contrast, the filter unit of the present invention narrows the bandwidth when the temperature difference between the detected temperature and the reference temperature is small even when the carrier frequency of the received standard radio wave is high. Further, even when the carrier frequency is low, the filter unit widens the bandwidth when the temperature difference between the detected temperature and the reference temperature is large.
In such a configuration, the bandwidth of the filter unit can be set to an appropriate value based on the actual temperature detected by the temperature sensor, and the reception sensitivity can be further improved.

  In the radio-controlled timepiece according to the invention, the filter unit includes a filter body incorporated in a circuit chip, an external resistor provided outside the circuit chip, and a switch for switching an external resistor connected to the filter body. Are preferably provided.

In the present invention, the resistance value of the external resistor connected to the filter body is changed in order to change the bandwidth of the frequency that is passed through the filter unit. At this time, in the present invention, the external resistor is provided outside the filter main body incorporated by a circuit chip such as an IC. And when changing the bandwidth of a filter part, the connection state in a switch is switched and the external resistance connected to a filter main body is switched.
The bandwidth setting in the filter unit varies depending on the type of the radio-controlled clock. Therefore, in order to set the optimal bandwidth for each standard radio wave, the resistance connected to the filter body is switched or exchanged at the prototype stage of the radio-controlled watch, and the filter bandwidth is set to the optimal value. It is preferable to set to. Here, in setting the optimum bandwidth of the filter unit, it may be necessary to replace the resistor. At this time, when a resistor connected to the filter main body is incorporated in the circuit chip, the resistor in the circuit chip is replaced, which is very complicated. On the other hand, in the present invention, since an external resistor is provided outside the circuit chip, it is easy to replace or switch the resistor, and the manufacturing efficiency can be improved.

In the radio-controlled timepiece of the invention, the filter unit includes a filter main body and an adjustment resistor connected in series to the filter main body, and the bandwidth is changed by changing a resistance value of the adjustment resistor. It is preferable to make it.
In the present invention, an adjustment resistor is connected in series to the filter body. In such a configuration, the bandwidth of the filter unit can be easily increased by reducing the resistance of the adjustment resistor as the reception frequency increases. The adjustment resistor may be configured to change the resistance value using a variable resistor, and a plurality of adjustment resistors having different resistance values are provided, and the resistance value is changed by switching the adjustment resistor connected to the filter body. It is good also as composition changed.

In the radio-controlled timepiece according to the aspect of the invention, it is preferable that the filter unit changes the bandwidth by changing a bias resistance of the filter unit.
In the present invention, the bandwidth of the filter unit can be easily widened by reducing the bias resistance as the reception frequency increases. As a method for changing the bias resistor, the resistance value may be changed using a variable resistor, or a plurality of bias resistors having different resistance values may be provided and the bias resistor connected to the filter body may be switched.

1 is a block diagram showing a schematic configuration of a radio-controlled timepiece according to a first embodiment of the present invention. The figure which shows the circuit structure of the band pass filter of 1st embodiment. The block diagram which shows schematic structure of the electromagnetic wave correction timepiece in 2nd embodiment of this invention. The figure which shows the receiving sensitivity with respect to the signal of the frequency component of a received signal. The figure which shows schematic structure of the band pass filter in other embodiment. The figure which shows the intermediate frequency which fluctuates with a temperature change.

[First embodiment]
Hereinafter, a first embodiment of the present invention will be described in detail based on the drawings.
[Basic configuration of radio-controlled watch]
As shown in FIG. 1, the radio-controlled timepiece 1 includes an antenna 2, a receiving circuit unit 3, a control circuit unit 4, a display unit 5, an external operation member 6, and a crystal oscillator that is a reference signal generating unit. And a reference oscillation circuit 47 provided.
The antenna 2 receives a long-wave standard radio wave (hereinafter sometimes abbreviated as “standard radio wave”), and outputs the received standard radio wave to the receiving circuit unit 3.
The receiving circuit unit 3 demodulates the received signal of the standard radio wave received by the antenna 2 and outputs it to the control circuit unit 4 as TCO (Time Code Out). A detailed description of the receiving circuit unit 3 will be described later.

The control circuit unit 4 decodes the input TCO to generate a TC (time code), and sets the time of the time counter 43 based on the generated TC. Further, the control circuit unit 4 displays the time of the time counter 43 on the display unit 5. Further, the control circuit unit 4 outputs a control signal to the receiving circuit unit 3.
The detailed description of the control circuit unit 4 will be described later.

  The display unit 5 is driven and controlled by the drive circuit unit 44 of the control circuit unit 4 and displays the time counted by the time counter 43. For example, the display unit 5 may include a liquid crystal panel and display the time on the liquid crystal panel. The display unit 5 may include a dial and a pointer, and the control circuit unit 4 may move the pointer and display the time. There may be.

  The external operation member 6 is constituted by, for example, a crown or a setting button, and outputs a predetermined operation signal to the control circuit unit 4 when operated by a user. As the operation signal, for example, a radio wave type setting data for setting the type of standard radio wave received by the antenna 2 (for example, JJY in Japan, WWVB in the United States, DCF77 in Germany, etc.), standard radio waves are received. Examples include correction request information for correcting the time.

  The reference oscillation circuit 47 includes a crystal resonator and outputs a reference signal having a predetermined reference clock frequency (for example, 32.768 kHz, which will be described as 32 kHz hereinafter) oscillated by the crystal resonator. The reference signal output from the reference oscillation circuit 47 is input to the control circuit unit 4. This signal is frequency-divided into a signal of 1 Hz by a frequency dividing circuit in the control unit 45.

[Receiver circuit configuration]
As shown in FIG. 1, the receiving circuit unit 3 includes a tuning circuit 31, a first amplifying circuit 32, a local oscillation signal generating unit 33, a frequency converting unit 34, and a main circuit constituting the received signal acquiring unit of the present invention. A band-pass filter (hereinafter sometimes abbreviated as “BPF”) 35, a second amplification circuit 36, a detection circuit 37, a binarization circuit 38, and a decoding that constitute the filter unit of the invention The circuit 39 is provided.

The tuning circuit 31 includes a capacitor, and the tuning circuit 31 and the antenna 2 constitute a parallel resonance circuit. The tuning circuit 31 causes the antenna 2 to receive a radio wave having a specific frequency. The tuning circuit 31 converts the standard radio wave received by the antenna 2 into a voltage signal and outputs the voltage signal to the first amplifier circuit 32 as a received signal.
Here, in the receiving circuit unit 3 of this embodiment, in addition to JJY (carrier frequency: 40 kHz, 60 kHz) which is a Japanese standard radio wave, DCF77 (carrier frequency: 77.5 kHz) which is a German standard radio wave, a standard of the United States. A radio wave WWVB (carrier frequency: 60 kHz) can be received. Note that the receiving circuit unit 3 may be configured to be able to receive standard radio waves in other regions such as BPC, which is a Chinese standard radio wave.
In the present embodiment, when the external operation member 6 is operated and radio wave type setting data is input, a control signal is input to the tuning circuit 31 from the control unit 45 of the control circuit unit 4 described later. As a result, the tuning circuit 31 is set to a state in which the standard radio wave corresponding to the radio wave type setting data can be received. That is, in the present embodiment, the control unit 45 constitutes a reception frequency setting unit of the present invention.
Here, an example in which the type of the standard radio wave to be received is switched by the external operation member 6 is shown. However, for example, a configuration in which a receivable standard radio wave is automatically detected by sequentially switching the reception frequency may be used. .

The first amplifier circuit 32 amplifies the reception signal input from the tuning circuit 31 to a constant amplitude.
An AGC circuit may be provided, and the gain of the first amplifier circuit 32 may be adjusted based on the envelope of the received signal detected by the detection circuit 37 using the AGC circuit.

The local oscillation signal generation unit 33 includes a local oscillation circuit 33A and a frequency generation unit 33B.
The local oscillation circuit 33A generates a signal having a predetermined frequency based on the reference signal having the reference clock frequency input from the control circuit unit 4.
The frequency generation unit 33B generates a local oscillation signal having a predetermined local oscillation frequency based on the signal input from the local oscillation circuit 33A. This local oscillation signal is oscillated at a local oscillation frequency for aligning the frequency of the received signal with a predetermined intermediate frequency in the frequency converter 34.
For example, in the present embodiment, the frequency converter 34 converts the reception frequency of the received signal (the carrier frequency of the received standard radio wave) into an intermediate frequency of 30 kHz. In this case, the frequency generation unit 33B generates a local oscillation frequency for converting the carrier frequency of the standard radio wave to an intermediate frequency of 30 kHz by dividing the frequency of the signal input from the local oscillation circuit 33A. Specifically, the frequency generation unit 33B outputs a local oscillation signal with a local oscillation frequency of 70 kHz when receiving a standard radio wave of 40 kHz, and a local oscillation frequency of 90 kHz when receiving a standard radio wave of 60 kHz. When a local oscillation signal is output and a standard radio wave of 77.5 kHz is received, a local oscillation signal having a local oscillation frequency of 107.5 kHz is output.

The frequency conversion unit 34 mixes the reception signal input from the first amplifier circuit 32 and the local oscillation signal from the local oscillation signal generation unit 33, and outputs a processing signal having an intermediate frequency. That is, the frequency conversion unit 34 converts the reception signal having the reception frequency into the processing signal having the intermediate frequency.
Here, assuming that the reception frequency is f ₀ and the local oscillation frequency is f ₁ , the frequency conversion unit 34 generates a processing signal having an intermediate frequency f _IF1 = | f ₀ −f ₁ | and outputs it to the BPF 35.
In the present embodiment, as described above, the local oscillation frequencies of 70 kHz, 90 kHz, and 107.5 kHz are respectively supplied from the local oscillation signal generation unit 33 corresponding to the standard radio waves of the carrier frequencies of 40 kHz, 60 kHz, and 77.5 kHz. A local oscillation signal is output. For this reason, the intermediate frequency of the processing signal converted by the frequency converter 34 is 30 kHz.

[Configuration of BPF]
FIG. 2 is a diagram illustrating a circuit configuration of the BPF 35.
The BPF 35 passes only the signal component of a predetermined frequency band among the processing signals input from the frequency converter 34 and blocks the signal of the frequency component outside the band.
As shown in FIG. 2, the BPF 35 sets a crystal filter (crystal oscillator) 35A that is a filter body, a first adjustment unit 35B connected in series to the crystal filter 35A, and a bias resistance of the BPF 35. A second adjustment unit 35C.
The first adjustment unit 35B includes a plurality of (for example, two) adjustment resistors 35D having different resistance values and a switch SW1 that switches between the adjustment resistors 35D connected to the crystal filter 35A. Similarly, the second adjustment unit 35C includes a plurality of (for example, two) bias resistors 35E having different resistance values, and a switch SW2 for switching the bias resistor 35E connected to the crystal filter 35A.

In the BPF 35, the switches SW1 and SW2 are switched according to the carrier frequency of the standard radio wave (the reception frequency of the reception signal), and the frequency bandwidth is switched.
As described above, in this embodiment, the local oscillation signal generation unit 33 generates a local oscillation signal based on the reference signal oscillated from the reference oscillation circuit 47. Here, the crystal oscillator of the reference oscillation circuit 47 is shifted in the reference clock frequency oscillated due to the influence of temperature change. Therefore, the local oscillation signal generated by the local oscillation signal generation unit 33 also causes a frequency shift corresponding to the fluctuation of the reference clock frequency. At this time, the higher the frequency of oscillation, the greater the amount of frequency deviation.
For example, as a temperature characteristic of the crystal oscillator of the reference oscillation circuit 47, when the frequency characteristic fluctuates by −50 PPM due to a temperature change of −10 degrees, the local oscillation signals of 70 kHz, 90 kHz, and 107.5 kHz are respectively −3. The frequency fluctuates by 5 kHz, −4.5 kHz, and −5.4 kHz. Accordingly, the frequency of the processing signal generated in the frequency converter 34 also varies by the same amount, and the frequency fluctuation value increases as the carrier frequency of the standard radio wave increases (see FIG. 6).
In such a case, if the bandwidth of the BPF 35 is fixed to a value corresponding to a standard radio wave of 40 kHz, the necessary signal components are blocked by the BPF 35 when receiving a standard radio wave of 60 kHz or 77.5 kHz. The reception sensitivity may be reduced. On the other hand, the BPF 35 of the present embodiment suppresses deterioration of reception sensitivity by changing the bandwidth (changing the Q value) corresponding to the frequency of each standard radio wave.

Specifically, when the radio-controlled timepiece 1 is manufactured, a combination of resistors (switch SW1 and switch SW2 connection settings) for setting the bandwidth of the BPF 35 to an optimum value with respect to the standard radio wave received is measured in advance. The connection measurement data is stored in the storage unit 42, for example. When the external operation member 6 is operated and the radio wave type setting data is input, the control unit 45 of the control circuit unit 4 reads the connection setting corresponding to the radio wave type setting data from the storage unit 42, and sends it to the BPF 35. A control signal for switching the switch SW1 and the switch SW2 is output. Thereby, the switch SW1 and the switch SW2 of the BPF 35 are switched to the connection state corresponding to the type of the standard radio wave, and the bandwidth of the frequency component that allows the signal to pass is changed in the BPF 35.
Table 1 shows a setting example of the bandwidth of the BPF 35 in the present embodiment.

In this embodiment, in order to generate a processing signal having an intermediate frequency (30 kHz) for each standard radio wave having a carrier frequency of 40 kHz, 60 kHz, or 77.5 kHz, a local oscillation is generated from the local oscillation signal generation unit 33, respectively. A local oscillation signal having a frequency of 70 kHz, 90 kHz, or 107.5 kHz is output. Here, as described above, when the temperature characteristic of the crystal resonator of the reference oscillation circuit 47 has a frequency variation of −50 PPM due to a temperature change of −10 degrees, each local oscillation frequency (70 kHz, 90 kHz, 107.5 kHz) The local oscillation signals fluctuate by −3.5 kHz, −4.5 kHz, and −5.4 kHz, respectively.
In this embodiment, in order to suppress a decrease in reception sensitivity due to the frequency fluctuation, the 3 dB bandwidth of the BPF 35 is twice the frequency fluctuation value with respect to the carrier frequencies of 40 kHz, 60 kHz, and 77.5 kHz of the standard radio wave. Set to 7 Hz, 9 Hz, and 10.8 Hz. Therefore, for example, even for JJY having the same time code, the bandwidth of the BPF 35 when receiving the standard radio wave of 60 kHz is set wider than the bandwidth of the BPF 35 when receiving the standard radio wave of 40 kHz. Further, even when the time codes are different as in JJY (60 kHz) and WWVB, the bandwidth of the BPF 35 is set to the same value when the carrier frequency is the same.

As a result, even when a shift in the intermediate frequency of the processing signal due to a temperature change occurs, the inconvenience that the signal component necessary for time correction is blocked by the BPF 35 can be avoided. Can be improved.
In the above example, the processing signal of the intermediate frequency is generated by the upper heterodyne method. However, the lower heterodyne using the local oscillation signal having the local oscillation frequency lower than the reception frequency (carrier frequency) of the reception signal. A method may be used. Even in this case, it is necessary to increase the local oscillation frequency as the reception frequency (carrier frequency) is higher, and the amount of deviation due to temperature is larger than that when the reception frequency is low. Therefore, as described above, the reception sensitivity can be improved by increasing the bandwidth of the BPF 35 as the carrier frequency of the standard radio wave increases.

The second amplification circuit 36 further amplifies the reception signal input from the BPF 35 with a fixed gain.
The detection circuit 37 includes a rectifier (not shown) and a low-pass filter (LPF) (not shown), and is obtained by rectifying, filtering, and filtering the received signal input from the second amplifier circuit 36. The envelope signal thus output is output to the binarization circuit 38.

  The binarization circuit 38 is composed of, for example, a binarization comparator. This binarization comparator is a comparator having hysteresis, and compares the envelope signal input from the detection circuit 37 with a reference voltage (threshold value) having a predetermined voltage, so that the binarization signal, that is, Outputs the TCO signal. The envelope signal is noisy, and flickering of the TCO signal can be suppressed by providing the binary comparator with a hysteresis of several mV.

  Specifically, the binarization circuit 38 determines that the signal having an H level (high level) voltage when the voltage of the envelope signal exceeds the reference voltage, and the voltage of the envelope signal is equal to or lower than the reference voltage. In this case, an L level (low level) signal having a voltage value lower than that of the H level signal is output to the control circuit unit 4 as a TCO signal. When the voltage of the envelope signal is higher than the reference voltage, the control circuit unit 4 uses the L level as the TCO signal, and the L level when the voltage of the envelope signal is lower than the reference voltage. It is also possible to configure so as to output to

  The binarization circuit 38 may use an AD converter and a level selection unit. For example, when a 10-bit AD converter is used as an AD converter that digitizes an analog signal after envelope detection, 10 digital signals are output to the level selection unit. Therefore, the level selection unit may binarize the 10-bit signal of the AD converter at a predetermined level based on the control signal to obtain a TCO output.

  The decode circuit 39 is connected to the control circuit unit 4 described later via a serial communication line. The decode circuit 39 decodes the control signal input from the control circuit unit 4 and outputs it to the binarization circuit 38 or the like.

[Configuration of control circuit section]
As described above, the control circuit unit 4 controls the operation of the reception circuit unit 3, and specifically controls the decoding circuit 39 of the reception circuit unit 3 to operate the reception circuit unit 3. A signal and a control signal for setting a reference voltage of the binarization circuit 38 are output. In addition, the control circuit unit 4 decodes the TCO signal input from the binarization circuit 38 and sets the time of the time counter 43 based on the time code generated by decoding. Furthermore, the control circuit unit 4 displays the time of the time counter 43 on the display unit 5.
As shown in FIG. 1, the control circuit unit 4 includes a TCO decoding unit 41 as a time code decoding unit, a storage unit 42 as a storage unit, a time counter 43, a drive circuit unit 44, a control unit 45, It is configured with. Note that the reference signal output from the reference oscillation circuit 47 is input to the control unit 45.

  The TCO decoding unit 41 decodes the TCO signal input from the binarization circuit 38 of the receiving circuit unit 3 and extracts a time code (TC) having date information and time information included in the TCO signal. Then, the TCO decoding unit 41 outputs the extracted TC to the control unit 45. Note that the TCO decoding unit 41 of this embodiment includes a plurality of types of standard radio waves such as JJY which is a Japanese standard radio wave, WWVB which is a standard radio wave of the United States, DCF77 which is a standard radio wave of Germany, and BPC which is a standard radio wave of China. The time code can be decoded and output.

  The storage unit 42 is a memory that stores various data, programs, and the like necessary for controlling the reception circuit unit 3 by the control circuit unit 4. The various data includes connection setting data of the switches SW1 and SW2 for switching the bandwidth of the BPF 35 as described above.

The time counter 43 counts time based on the reference signal output from the reference oscillation circuit 47. Specifically, the time counter 43 includes a second counter that counts seconds, a minute counter that counts minutes, and an hour counter that counts hours.
For example, when a 1 Hz reference signal is output, the second counter is a counter that loops the signal at 60 counts, that is, 60 seconds. The minute counter is a counter that counts once when the reference signal of 1 Hz is multiplied 60 times and loops at 60 counts, that is, 60 minutes. The hour counter is a counter that counts once when the 1 Hz reference signal is coefficiented 3600 times and loops in 24 counts, that is, 24 hours.
The minute counter may be configured to count up the minute counter by outputting a signal from the second counter to the minute counter every time the second counter counts 60 times. Similarly, the hour counter may be configured to output a signal from the minute counter to the hour counter every time the minute counter counts 60 to count up the hour counter.

  The drive circuit unit 44 controls the display state of the display unit 5 based on the time display control signal output from the control unit 45 and causes the display unit 5 to display the time. For example, when the display unit 5 includes a liquid crystal panel and displays the time on the liquid crystal panel, the drive circuit unit 44 controls the liquid crystal panel based on the time display control signal and displays the time on the liquid crystal panel. Let When the display unit 5 has a dial and a pointer, the drive circuit unit 44 outputs a pulse signal to the stepping motor that drives the pointer and moves the pointer by the driving force of the stepping motor.

  The control unit 45 is driven based on the drive frequency input from the reference oscillation circuit 47 and performs various control processes. That is, the control unit 45 outputs the TC input from the TCO decoding unit 41 to the time counter 43 and corrects the count of the time counter 43. Further, the control unit 45 outputs a time display control signal for causing the display unit 5 to display the time counted by the time counter 43 to the drive circuit unit 44.

  Further, as described above, the control unit 45 also functions as a reception frequency setting unit of the present invention, and sets the carrier frequency of the standard radio wave to be received based on the radio wave type setting data when the external operation member 6 is operated. . Then, the control unit 45 outputs a control signal to the tuning circuit 31 to receive the set standard radio wave. Further, the control unit 45 reads the connection settings of the switches SW1 and SW2 corresponding to the set carrier frequency from the storage unit 42, and outputs a control signal for switching the connection state of the switches SW1 and SW2 to the BPF 35.

The control unit 45 and the decode circuit 39 are connected by a serial communication line, and the control signal is input to the decode circuit 39 via the serial communication line. As a result, a control signal for controlling the receiving circuit unit 3 can be output to the receiving circuit unit 3 via the decoding circuit 39.
Here, in the serial communication between the control unit 45 and the reception circuit unit 3, a two-line synchronous interface capable of bidirectional communication between the control unit 45 and the reception circuit unit 3 is used to perform bidirectional communication. Serial communication may be performed. In such a case, after outputting a control signal from the control unit 45 to the receiving circuit unit 3, the receiving circuit unit 3 retransmits the received and recognized control signal to the control unit 45 and outputs it from the control unit 45. By confirming the data difference between the control signal and the input control signal, serial communication with higher reliability can be performed.

[Effects of Embodiment]
In the radio-controlled timepiece 1 of this embodiment, when the radio wave type setting data is input by operating the external operation member 6, the control unit 45 sets the carrier frequency to be received and sets it for the tuning circuit 31. A control signal for receiving the standard radio wave of the carrier frequency is output. Further, the control unit 45 changes the connection state of the switch SW1 and the switch SW2 of the BPF 35 in accordance with the set carrier frequency, and changes the bandwidth of the BPF 35. At this time, the connection state of the switch SW1 and the switch SW2 is switched so that the bandwidth becomes wider as the carrier frequency is higher.
In such a configuration, when a received signal of a standard radio wave having a high carrier frequency (for example, 60 kHz or 77.5 kHz) is converted into an intermediate frequency by the frequency conversion unit 34, the amount of frequency deviation increases due to the influence of temperature. Even in this case, since the bandwidth of the BPF 35 is set wide, signal components necessary for time correction are not blocked, and a decrease in reception sensitivity can be suppressed. Further, when a standard radio wave (for example, 40 kHz) having a low carrier frequency band is received, the bandwidth of the BPF 35 is narrowed, so that unnecessary signal components such as noise can be blocked and reception sensitivity can be improved.

  In the present embodiment, reception processing of the superheterodyne method is performed, and the local oscillation signal generation unit 33 is based on the reference signal of the fundamental frequency output from the reference oscillation circuit 47 provided with a crystal resonator, in the frequency conversion unit 34. A local oscillation signal for generating an intermediate frequency processing signal is generated. Then, the frequency conversion unit 34 mixes the reception signal acquired by the tuning circuit 31 and the local oscillation signal generated by the local oscillation signal generation unit 33 to generate an intermediate frequency processing signal. By using such a superheterodyne system, even when receiving standard radio waves of different carrier frequencies, it is possible to align to one intermediate frequency, and a signal necessary for time correction by one BPF 35 Components can be extracted, and the configuration of the radio-controlled timepiece 1 can be simplified.

The BPF 35 of the present embodiment includes a crystal filter 35A and a first adjustment unit 35B connected in series to the crystal filter 35A. The first adjustment unit 35B includes a plurality of adjustment resistors 35D having different resistance values, and a switch SW1 that switches a connection state between the adjustment resistors 35D and the crystal filter 35A.
In such a configuration, the adjustment resistor 35D connected to the crystal filter 35A can be easily changed by simply switching the connection state of the switch SW1 in accordance with the carrier frequency of the standard radio wave. Bandwidth can be switched.

In addition, the BPF 35 of the present embodiment includes a second adjustment unit 35C, and the second adjustment unit 35C includes a switch SW2 that switches between a plurality of bias resistors 35E having different resistance values and a bias resistor 35E connected to the crystal filter 35A. Prepare.
Therefore, similarly to the above, the bias resistor 35E connected to the crystal filter 35A can be easily changed by simply switching the connection state of the switch SW2 in accordance with the carrier frequency of the standard radio wave. The filter bandwidth of the crystal filter 35A can be switched.

[Second Embodiment]
Next, 2nd embodiment which concerns on this invention is described based on drawing.
In the radio-controlled timepiece 1 of the first embodiment described above, the bandwidth of the signal passed through the BPF 35 is switched depending on the carrier frequency of the received standard radio wave. On the other hand, in the second embodiment, the first embodiment is provided in that the temperature sensor is provided and the bandwidth of the BPF is switched based on the temperature detected by the temperature sensor and the carrier frequency of the received standard radio wave. It differs from the form.
FIG. 3 is a block diagram showing a schematic configuration of the radio-controlled timepiece 1A in the second embodiment. FIG. 4 is a diagram illustrating the reception sensitivity with respect to the frequency component of the received signal, where “0” on the horizontal axis indicates the intermediate frequency, and Δf indicates the amount of deviation from the intermediate frequency. As shown in FIG. 4, when the Q value is large (the bandwidth of the BPF 35 is narrow), the reception sensitivity of a signal component having a large deviation from the intermediate frequency is deteriorated, but the reception sensitivity at the intermediate frequency is increased. On the other hand, when the Q value is small (the bandwidth of the BPF 35 is wide), a certain degree of reception sensitivity can be obtained even for a signal with a large amount of deviation from the intermediate frequency, compared to when the Q value is large. Reception sensitivity is lowered.
In the description of the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  As shown in FIG. 3, the radio wave correction timepiece 1 </ b> A of the present embodiment is provided with a temperature sensor 7. The temperature sensor 7 detects the temperature and outputs a detection signal based on the detected temperature to the control unit 45 of the control circuit unit 4.

In the present embodiment, the bandwidth of the BPF 35 is switched based on the temperature detected by the temperature sensor 7 in addition to the carrier frequency of the standard radio wave.
For example, as shown in FIG. 6, when a standard radio wave having a carrier frequency of 77.5 kHz is received, the amount of deviation of the intermediate frequency converted by the frequency converter 34 is small if it is close to a reference temperature (for example, 25 degrees). Become. Up to such a case, if the bandwidth in the BPF 35 is widened (Q value is reduced), the reception sensitivity at the intermediate frequency is lowered as shown in FIG.
On the other hand, when a standard radio wave with a carrier frequency of 40 kHz is received, the amount of deviation of the intermediate frequency due to temperature is smaller than when the carrier frequency is high. However, if the temperature difference from the reference temperature increases, the amount of deviation of the intermediate frequency also increases. Therefore, if the bandwidth of the BPF 35 is narrow, there is a possibility that necessary signal components may be blocked and reception sensitivity may be reduced.

Therefore, the storage unit 42 of the present embodiment stores the connection settings of SW1 and SW2 of the BPF 35 corresponding to the above pattern.
For example, as shown in FIG. 6, a standard radio wave of 40 kHz received at a temperature T ₁ , a standard radio wave of 60 kHz received at a temperature T ₂ , and a standard radio wave of 77.5 kHz received at a temperature T ₃ are When the conversion unit 34 converts the signal to a processing signal, the amount of deviation from the intermediate frequency becomes substantially the same amount (ΔF ₁ ). Therefore, the storage unit 42, 40 kHz standard radio at these temperatures _{T 1,} the standard radio wave of 60kHz at a temperature _{T 2,} and a connection setting switch SW1, SW2 of BPF35 for standard radio 77.5kHz at a temperature _{T 3} The data for setting the filter bandwidth corresponding to the deviation amount ΔF ₁ is stored.
Focusing only on the temperature T ₁ , the deviation amount when the 40 kHz standard radio wave is converted to the intermediate frequency is ΔF ₁ , and the deviation amount when the 60 kHz standard radio wave is converted to the intermediate frequency is ΔF ₂ ( ΔF ₂ > ΔF ₁ ), and the amount of deviation when the standard radio wave of 77.5 kHz is converted to the intermediate frequency is ΔF ₃ (ΔF ₃ > ΔF ₂ ). Therefore, for the same temperature (excluding the vicinity of the reference temperature), data that widens the bandwidth of the BPF 35 (decreases the Q value) is stored in the storage unit 42 as the carrier frequency increases.
Then, the control unit 45 sets the connection setting of the switches SW1 and SW2 of the BPF 35 from the storage unit 42 based on the detected temperature detected by the temperature sensor 7 and the radio wave type setting data input by operating the external operation member 6. Read and output a control signal to the BPF 35. Thereby, the BPF 35 is set to a bandwidth based on the carrier frequency of the received standard radio wave and the detected temperature.

[Operational effects of this embodiment]
In the radio-controlled timepiece 1A of the present embodiment, the temperature sensor 7 is provided, and the control unit 45 performs a carrier frequency based on the detected temperature detected by the temperature sensor 7 and the radio wave type setting data input by the external operation member 6. Based on the above, the bandwidth of the BPF 35 is switched.
For this reason, even if the carrier frequency is high, if the detected temperature is near the reference temperature where the amount of deviation of the intermediate frequency converted by the frequency converter 34 is small, the bandwidth of the BPF 35 is set narrow, and the signal The reception sensitivity can be improved by removing the noise component. Even when the carrier frequency is low, if the temperature difference between the detected temperature and the reference temperature is large, the bandwidth of the BPF 35 is set wide so that signal components necessary for time correction can be prevented from being blocked. The reception sensitivity can be improved.

[Other Embodiments]
It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, the BPF 35 may be incorporated in a circuit chip (for example, an IC or the like) that constitutes the receiving circuit unit 3, or only a part may be provided outside the circuit chip as shown in FIG.
In the example shown in FIG. 5, this BPF 35 includes a crystal filter 35A, a switch SW1, and a switch SW2 incorporated in the circuit chip 3A, and an adjustment resistor 35D and a bias resistor 35E as external resistors outside the circuit chip 3A. Is provided.
By adopting such a configuration, for example, the efficiency when setting the bandwidth of the BPF 35 in the manufacturing process of the radio-controlled timepiece 1 or 1A can be improved. That is, in the radio-controlled timepieces 1 and 1A, the resistance values of the adjustment resistor 35D and the bias resistor 35E used for setting the bandwidth of the BPF 35 are different depending on the type of the timepiece. Therefore, these adjustment resistor 35D and bias resistor 35E need to be adjusted so that the standard radio wave is received and the bandwidth of the BPF 35 becomes a desired value in the manufacturing stage (prototype stage). At this time, if the adjustment resistor 35D and the bias resistor 35E are incorporated in the circuit chip 3A, a complicated operation such as reassembling the circuit chip 3A is required when the resistors 35D and 35E need to be replaced. Accompany. On the other hand, when the resistors 35D and 35E are external resistors, these resistors 35D and 35E can be easily replaced, the work load can be reduced, and the production efficiency is dramatically improved. Can be made.

  In each of the above embodiments, the control unit 45, which is the reception frequency setting unit of the present invention, sets the carrier frequency of the received standard radio wave based on the radio wave type setting data input by operating the external operation member 6. However, it is not limited to this. For example, as described above, the frequency received by the tuning circuit 31 is sequentially switched. When the standard radio wave is received by the tuning circuit 31, the control unit 45 sets the carrier frequency of the standard radio wave as the carrier frequency to be received. And it is good also as a structure which switches the bandwidth of BPF35.

  Furthermore, in the first embodiment, the bandwidth of the BPF 35 is set according to the carrier frequency of the standard radio wave. However, the bandwidth of the BPF 35 may be changed based on the reception result. For example, in the reception process, when the TCO cannot be acquired due to the influence of noise or the like and the reception process results in an error, the control unit 45 outputs a control signal to switch the switches SW1 and SW2 of the BPF 35, and the bandwidth of the BPF 35 You may carry out the processing which spreads. With such a configuration, errors in reception processing can be avoided, and reception sensitivity can be further improved.

  The BPF 35 has a configuration in which the bandwidth is changed by switching the connection state of the switches SW1 and SW2. However, for example, a variable resistor is connected to the BPF 35, and the resistance of the variable resistor is controlled by the control unit 45. A configuration in which the value is changed continuously or stepwise may be employed.

  In each of the above embodiments, the reference oscillation circuit 47 including a crystal resonator is exemplified as the reference signal generation unit that outputs a reference signal having a reference frequency. For example, an oscillation circuit using a ceramic oscillator or a silicon oscillator is used. May be used.

  Moreover, although the quartz filter 35A was illustrated as a filter main body of BPF35, you may use a ceramic filter, a mechanical filter, etc., for example.

Further, as a specific configuration example for changing the bandwidth of the BPF 35, the BPF 35 includes a first adjustment unit 35B and a second adjustment unit 35C. However, for example, only the first adjustment unit 35B is provided, and the second adjustment unit 35B is provided. A configuration in which the adjustment unit 35C is not provided, a configuration in which only the second adjustment unit 35C is provided, and the first adjustment unit 35B is not provided may be employed.
In addition, the specific structure and procedure for carrying out the present invention can be changed as appropriate to other structures and the like within the scope of achieving the object of the present invention.

  DESCRIPTION OF SYMBOLS 1,1A ... Radio wave correction clock, 2 ... Antenna, 3 ... Reception circuit part, 4 ... Control circuit part, 5 ... Display part, 6 ... External operation member, 7 ... Temperature sensor, 31 ... Tuning circuit (reception signal acquisition part) 33 ... Local oscillation signal generation unit, 33A ... Local oscillation circuit, 33B ... Frequency generation unit, 34 ... Frequency conversion unit, 35 ... Band pass filter (BPF: filter unit), 35A ... Quartz crystal filter (filter body), 35B ... First adjustment unit, 35C ... second adjustment unit, 35D ... adjustment resistor, 35E ... bias resistance, 42 ... storage unit, 43 ... time counter (internal clock), 45 ... control unit (reception frequency setting unit), SW1, SW2 is a switch.

Claims (6)

A radio-controlled timepiece that can receive a plurality of standard radio waves having different carrier frequencies and corrects the time of the internal clock based on any one of the plurality of standard radio waves,
A reception frequency setting unit for setting a carrier frequency of a standard radio wave to be received among a plurality of standard radio waves,
A reception signal acquisition unit that receives the standard radio wave of the carrier frequency set by the reception frequency setting unit and acquires a reception signal having the carrier frequency as a reception frequency;
A frequency converter that converts the acquired received signal into a processing signal having a predetermined intermediate frequency;
A filter unit that extracts a frequency component signal of a predetermined bandwidth from the processing signal;
With
The radio wave correction timepiece, wherein the filter unit widens the bandwidth as the carrier frequency set by the reception frequency setting unit is higher. The radio-controlled timepiece according to claim 1,
A reference signal generator for generating a reference signal of a predetermined reference frequency;
A local oscillation signal generator for generating a local oscillation signal of a predetermined local oscillation frequency from the reference signal;
With
The frequency conversion unit synthesizes the reception signal and the local oscillation signal, and converts the reception signal into the processing signal. In the radio-controlled timepiece according to claim 1 or 2,
Equipped with a temperature sensor to detect the temperature,
The radio wave correction timepiece, wherein the filter unit changes the bandwidth based on a temperature detected by the temperature sensor and a carrier frequency set by the reception frequency setting unit. The radio-controlled timepiece according to any one of claims 1 to 3,
The filter section is
A filter body built into the circuit chip;
An external resistor provided outside the circuit chip;
And a switch for switching an external resistor connected to the filter body. The radio-controlled timepiece according to any one of claims 1 to 4,
The filter section includes a filter main body and an adjustment resistor connected in series to the filter main body, and the bandwidth is changed by changing a resistance value of the adjustment resistor. clock. The radio-controlled timepiece according to any one of claims 1 to 5,
The radio wave correction timepiece, wherein the filter unit changes the bandwidth by changing a bias resistance of the filter unit.

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