JP2011112428A - Radio-controlled timepiece and control method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio-controlled timepiece for improving a receiving performance when a standard radio wave is received. <P>SOLUTION: The radio-controlled timepiece 1 includes: an antenna 2 for receiving and demodulating the standard radio wave, and a receiving circuit 3; a control circuit 4 for controlling the receiving circuit 3; and a time correction means for correcting time information based on the demodulated signal. The receiving circuit 3 includes: a first amplification circuit 32 for amplifying the received signal; an envelope detection circuit 35 for detecting the amplified signal, and outputting an envelope signal; a binarization circuit 37 for comparing the envelope signal with a reference voltage, and outputting a binary signal; and a VREF switching circuit 38 for setting a voltage value of the reference voltage in the binarization circuit 37 to a marker obtaining voltage value or a time code obtaining voltage value. The control circuit 4 includes a controller 47 for controlling the VREF switching circuit 38. When a marker is obtained, the marker obtaining voltage value is set by the controller 47. When a time code is obtained, the time code obtaining voltage value is set by the controller 47. <P>COPYRIGHT: (C)2011,JPO&INPIT

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, and a control method therefor.

A radio-controlled timepiece that receives a standard radio wave and corrects the time is known (see, for example, Patent Documents 1 and 2).
The standard radio wave is amplitude-modulated, and the radio wave correction watch extracts an envelope of a received signal with a filter or the like in a receiving circuit, and then compares an envelope signal and a reference voltage (threshold) with a comparator (comparator) or the like. Is provided with a binarization circuit for binarization. The radio-controlled timepiece obtains time information based on the time code signal obtained by the binarization circuit and displays the time.

  In Patent Documents 1 and 2, the reference voltage (threshold value) is set in accordance with the type of standard radio wave to reduce time code error detection due to the influence of noise or the like.

JP 2008-20298 A JP 2007-139705 A

By the way, each standard radio wave transmits time information by transmitting signals of 1, 0 and P every second. Here, since the duty of each signal (the ratio of the Hi level period in each signal) is different, the voltage level of the envelope signal is also different for each signal.
For example, the voltage of the envelope signal is configured to increase during the Hi level period of each signal and decrease during the Low level period. When a signal with a duty of 50% is used as a reference, the duty is 20%, etc. For a signal with a short level period, the peak voltage of the envelope signal tends to be lower than when the duty is 50%. In addition, for a signal with a short Low level period such as a duty of 80%, the bottom voltage of the envelope signal is likely to be higher than when the duty is 50%.

Therefore, even when the reference voltage (threshold value) of the binarization circuit is set for each standard radio wave, there is a possibility that the reference voltage is not appropriate for individual signals of each standard radio wave. For example, in the case of a radio wave in which the reference voltage is set based on a signal with a duty of 50%, the peak voltage is low for a signal with a small duty, and therefore, there is a problem that the signal cannot be detected correctly because it does not exceed the reference voltage.
Similarly, when the duty is large, the bottom voltage is high, so that the voltage is not less than the reference voltage. In this case, there is a problem that the signal cannot be detected correctly.
In this way, when the reference voltage of the binarization circuit is set according to the type of the standard radio wave to be received, the reception performance can be improved compared to the case where the reference voltage is made constant regardless of the type of the standard radio wave. However, there was a problem that there was a limit to the performance improvement.

  An object of the present invention is to provide a radio-controlled timepiece that can improve the reception performance when receiving a standard radio wave, and a control method therefor.

  The radio-controlled timepiece according to the present invention includes a receiving unit that receives and demodulates a standard radio wave, a control unit that controls the receiving unit, and a time correcting unit that corrects time information based on a signal demodulated by the receiving unit. A radio frequency correction watch comprising: a signal amplifying unit for amplifying the reception signal of the standard radio wave; a detection unit for detecting the amplified reception signal and outputting an envelope signal; and The comparison unit that compares the envelope signal and the reference voltage and outputs a binarized signal, and the voltage value of the reference voltage of the comparison unit is different from the marker acquisition voltage value or the marker acquisition voltage value A reference voltage setting unit that sets a voltage value for obtaining a time code that is a voltage value, the control means includes a reference voltage control unit that controls the reference voltage setting unit, and the reference voltage control unit includes a standard radio wave Remove the marker When obtaining a marker, the voltage value of the reference voltage is set to the voltage value for obtaining the marker, and when obtaining a time code for obtaining a time code of a standard radio wave, the voltage value of the reference voltage is set to the voltage value for obtaining the time code. It is characterized by setting.

According to the present invention, when the standard radio wave is received, the reference voltage of the comparison unit is individually set when the marker is acquired and when the time code is acquired. For this reason, when the level of the envelope signal differs between a signal representing the marker (P, M signal) and a signal representing a time code other than the marker (for example, 1 signal and 0 signal), the respective signals are detected. It can be set to a reference voltage suitable for Therefore, according to the present invention, when receiving a standard radio wave, each signal can be detected with high accuracy, the influence of noise can be reduced, and reception performance can be improved.
Since the reception performance can be improved, correct time information can be acquired, and the time displayed can be corrected correctly based on the acquired time information, so that a radio time correction clock with high time accuracy can be configured. .

  In the radio-controlled timepiece according to the invention, the receiving unit includes a bandpass filter capable of changing a bandwidth, and the control unit includes a bandwidth control unit that sets a bandwidth of the bandpass filter, and the bandwidth The control unit sets a bandwidth of the bandpass filter according to a predetermined condition, and the reference voltage control unit sets the marker acquisition voltage value and the time code acquisition voltage value to the set bandpass filter. It is preferable to set according to the bandwidth.

According to the present invention, since the bandwidth of the bandpass filter can be changed according to a predetermined condition, it is possible to obtain an appropriate reception characteristic according to the condition.
For example, when the bandwidth of the bandpass filter can be switched in two stages, a first bandwidth having a narrow bandwidth (for example, 5 Hz) and a second bandwidth having a wider bandwidth (for example, 10 Hz), When the second bandwidth is set, the current consumption can be reduced, the response of the detection signal is good, and the temperature change is strong as compared with the case where the first bandwidth is set. On the other hand, there is a drawback that it is vulnerable to noise.
Therefore, considering the characteristics of each bandwidth and setting the bandwidth of the bandpass filter according to a predetermined condition, the overall reception performance can be improved.
Also, the waveform of the detection signal (envelope signal level) and the like vary depending on the bandwidth of the bandpass filter, but in the present invention, the marker acquisition voltage value depends on the set bandwidth of the bandpass filter. Since the voltage value for obtaining the time code is set, even when the bandwidth is changed, the marker signal and the time code can be reliably and accurately detected, and the reception performance can also be improved in this respect.

  In the radio-controlled timepiece according to the aspect of the invention, the bandpass filter is configured to be capable of switching a bandwidth between a first bandwidth and a second bandwidth wider than the first bandwidth. The control unit may set the second bandwidth at the start of reception, and may set the first bandwidth when the marker cannot be acquired or the time code cannot be acquired after the start of reception. preferable.

According to the present invention, as a condition for setting the bandwidth, the bandwidth control unit sets a condition as to whether or not reception is started and a condition as to whether or not a marker or a time code has been acquired. Set the bandwidth according to the conditions.
The bandpass filter is set to the second bandwidth at the start of reception, and is set to the first bandwidth only when the marker and time code cannot be detected and acquired after the start of reception. For this reason, since the second bandwidth is set during normal reception, the current consumption can be reduced and the response of the detection signal is better than when receiving with the first bandwidth set. It has the advantage of being resistant to temperature changes.
If the marker or time code cannot be detected or acquired after the start of reception, the first bandwidth is set to be more resistant to noise than the second bandwidth. The probability of acquiring a code can be improved. Therefore, overall reception performance can be improved.

  The radio-controlled timepiece according to the present invention further includes a temperature sensor that measures temperature, and the bandpass filter has a bandwidth that is a first bandwidth and a second bandwidth that is wider than the first bandwidth. When the temperature measured by the temperature sensor is within a preset temperature range, the bandwidth controller is set to the first bandwidth and measured by the temperature sensor. When the temperature is outside the temperature range, the second bandwidth is set.

  According to the present invention, since the bandwidth is set by measuring the ambient temperature, the reception sensitivity can be changed by changing the bandwidth to a wide bandwidth when the center frequency of the bandpass filter varies greatly. Can be suppressed.

  In the radio-controlled timepiece according to the aspect of the invention, the bandpass filter is configured to be capable of switching a bandwidth between a first bandwidth and a second bandwidth wider than the first bandwidth. When the standard radio wave to be received is either the Japanese standard radio wave JJY or the American standard radio wave WWVB, the control unit sets the first bandwidth, and the standard radio wave to be received is the German standard radio wave DCF77 or In the case of any one of British standard radio waves MSF, it is preferable to set the second bandwidth.

According to the present invention, when the pulse duty differs greatly between the signals “1”, “0”, “M or P”, such as JJY and WWVB, the bandwidth of the bandpass filter is set to the first bandwidth. Even if the response of the detection signal is somewhat poor, each signal can be discriminated. On the other hand, if the first bandwidth is set, the influence of external noise can be reduced. For this reason, in JJY and WWVB, the reception performance can be improved by setting the bandwidth of the bandpass filter to the first bandwidth.
On the other hand, when the difference in pulse duty between the signals “1” and “0” is small, such as DCF77 and MSF, if the rising response of the detection signal is poor, one signal is erroneously recognized as the other signal. There is a high possibility that Therefore, if the bandwidth of the bandpass filter is set to the second bandwidth to improve the response of the detection signal, each signal with a small difference in pulse duty can be detected in response to changes in the detection waveform. It can be distinguished and determined. For this reason, in DCF77 and MSF, the reception performance can be improved by setting the bandwidth of the bandpass filter to the second bandwidth.

  In the radio-controlled timepiece of the present invention, the receiving means is configured to be capable of receiving a plurality of standard radio waves, and the reference voltage setting unit sets the marker acquisition voltage value and the time code acquisition voltage value to the standard radio wave type. The reference voltage control unit, when acquiring a marker for acquiring a standard radio wave marker, sets the voltage value for the reference voltage to the marker acquisition voltage corresponding to the type of the standard radio wave to be received. It is preferable to set the voltage value of the reference voltage to the voltage value for time code acquisition corresponding to the type of the standard radio wave to be received when acquiring the time code to set the value and acquire the time code of the standard radio wave.

According to the present invention, since the marker acquisition voltage value is set according to the type of the standard radio wave to be received, even if the level of the envelope signal of the signal representing the marker is different for each standard radio wave, it is suitable for each level. The reference voltage value (marker acquisition voltage value) can be set. For this reason, the marker signal can be detected reliably and accurately, and the synchronization of the standard radio wave can be performed reliably.
In addition, since the time code acquisition voltage value is set according to the type of the standard radio wave to be received, even when the level of the envelope signal of the signal representing the time code (1 signal or 0 signal) is different for each standard radio wave A reference voltage (time code acquisition voltage value) suitable for each level can be set. For this reason, a time code can be detected reliably and accurately, and correct time information can be stably acquired.
For example, the marker acquisition voltage value and the time code acquisition voltage value for each standard radio wave are stored in advance in the storage unit, and data is read according to the type of standard radio wave to be received. The reference voltage setting unit may be controlled based on the data.

  The method for controlling a radio-controlled timepiece according to the present invention includes a receiving unit that receives and demodulates a standard radio wave, a control unit that controls the receiving unit, and a time at which time information is corrected based on a signal demodulated by the receiving unit. A correction method for a radio-controlled timepiece comprising a correction means, wherein the reception means amplifies the reception signal of the standard radio wave, and detects the amplified reception signal and outputs an envelope signal A detection unit that compares the envelope signal with a reference voltage and outputs a binarized signal; a voltage value of a reference voltage of the comparison unit; a voltage value for marker acquisition; or the marker acquisition A reference voltage setting unit that sets a voltage value for time code acquisition that is a voltage value different from the voltage value for use, and when acquiring a marker for acquiring a standard radio wave marker, the voltage value of the reference voltage is set to the marker acquisition voltage. And setting, the time of the time code acquisition for acquiring time code of the standard radio, characterized in that it comprises the steps of setting the voltage value of the reference voltage to the time code acquiring voltage values.

  In this radio-controlled timepiece control method, as with the radio-controlled timepiece, when receiving standard radio waves, each signal can be detected with high accuracy, the influence of noise can be reduced, and reception performance can be improved. A radio-controlled timepiece with high time accuracy can be configured.

1 is a block diagram showing a configuration of a radio wave correction timepiece according to a first embodiment of the present invention. It is a circuit diagram which shows an example of a band pass filter. It is a circuit diagram which shows the other example of a band pass filter. It is a circuit diagram which shows an example of a VREF switching circuit. It is a figure which shows the receiving pulse duty and amplitude change with respect to each signal of the standard radio wave "JJY" in Japan. It is a figure which shows the receiving pulse duty with respect to each signal of standard radio wave "WWVB" in the United States, and an amplitude change. It is a figure which shows the receiving pulse duty and amplitude change with respect to each signal of the standard radio wave "DCF77" in Germany. It is a figure which shows the receiving pulse duty and amplitude change with respect to each signal of the standard radio wave "MSF" in the United Kingdom. It is a figure which shows the time code format of the standard radio wave "JJY" in Japan. It is a figure which shows an example of a reference voltage setting table. It is a wave form diagram which shows a time code, a detection waveform, a reference voltage, and TCO. It is a flowchart which shows the reception process of 1st Embodiment. It is a flowchart which shows the reception process of 2nd Embodiment. It is a wave form diagram which shows the time code of 2nd Embodiment, a detection waveform, a reference voltage, and TCO. It is a flowchart which shows the reception process of 3rd Embodiment. It is a wave form diagram which shows the time code at the time of MSF reception, a detection waveform, and a reference voltage.

Hereinafter, a radio-controlled timepiece 1 according to a first embodiment of the present invention will be described with reference to the drawings.
[Configuration of radio-controlled clock]
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 resonator 48.
The antenna 2 receives a long-wave standard radio wave (hereinafter referred to as “standard radio wave”), and outputs the received standard radio wave signal to the reception 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). Therefore, the antenna 2 and the receiving circuit unit 3 constitute the receiving means of the present invention. A detailed description of the receiving circuit unit 3 will be described later.

  The control circuit unit 4 decodes the input TCO to generate TC (time code, time data), and sets the time of the time counter 43 based on the generated TC. In addition, the control circuit unit 4 controls the display unit 5 to display the time of the time counter 43. Further, the control circuit unit 4 outputs a control signal to the reception circuit unit 3. Therefore, the control circuit unit 4 constitutes the control means of the present invention. 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 46 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 to 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 crystal oscillator 48 for the reference clock outputs a predetermined reference signal (reference clock, for example, a 32.768 kHz signal). The reference signal output from the crystal oscillator 48 is input to the control circuit unit 4. ing.

[Configuration of receiving circuit section]
As shown in FIG. 1, the receiving circuit unit 3 includes a tuning circuit 31, a first amplifier circuit 32, a band-pass filter (hereinafter abbreviated as “BPF”) 33, a second An amplifier circuit 34, an envelope detection circuit 35, an AGC (Auto Gain Control) circuit 36 as an automatic gain control circuit, a binarization circuit 37, a VREF switching circuit 38 as a reference voltage setting unit, and a decoding circuit 39 And is configured.

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. In the receiving circuit unit 3 of this embodiment, in addition to the Japanese standard radio wave “JJY”, the standard radio wave “WWVB” in the United States, the standard radio wave “DCF77” in Germany, the standard radio wave “MSF” in the United Kingdom, etc. It is configured to receive standard radio waves.
Therefore, the antenna 2 and the tuning circuit 31 constitute a receiver that can receive a plurality of types of standard radio waves.

  The first amplifier circuit 32 adjusts the gain in accordance with a signal (AGC voltage) input from an AGC circuit 36 described later, and amplifies the received signal input from the tuning circuit 31 so as to be input to the BPF 33 as a constant amplitude. That is, according to the signal input from the AGC circuit 36, the first amplifying circuit 32 reduces the gain when the amplitude is large, and increases the gain when the amplitude is small. Amplify so that

  The band pass filter 33 is a filter that extracts a signal in a desired frequency band. That is, by passing through the band pass filter 33, other than the carrier wave component is removed from the received signal input from the first amplifier circuit 32.

As shown in FIG. 2, the bandpass filter 33 of the present embodiment includes a crystal resonator 331, resistors 332 and 333, and switches 334 and 335. The resistors 332 and 333 have different resistance values. In FIG. 2, the resistance value of the resistor 332 is set larger than the resistance value of the resistor 333. Each of the resistors 332 and 333 and the switches 334 and 335 are connected in parallel to the second amplifier circuit 34 constituted by an operational amplifier.
In the band-pass filter 33, one of the switches 334 and 335 is turned on and the other is turned off to change the bandwidth WB. That is, when the switch 334 is turned off and the switch 335 is turned on and only the resistor 333 having a small resistance value is connected, the bandwidth of the bandpass filter 33 is set to the first bandwidth WB1, and conversely, the switch 334 is turned on and switched. When 335 is turned off and the bandwidth of the bandpass filter 33 when only the resistor 332 having a large resistance value is connected is the second bandwidth WB2, WB1 <WB2.

As shown in FIG. 3, the band-pass filter 33 is connected in parallel to the resistor 341 connected in parallel to the second amplifier circuit 34 and in parallel to the second amplifier circuit 34. The resistors 342 and 343 and the switches 344 and 345 may be provided. Also in the band pass filter 33, the bandwidth WB can be changed by turning on one of the switches 344 and 345 and turning off the other.
The band-pass filter 33 is not limited to those shown in FIGS. 2 and 3, and various band-pass filters that can be used in a standard radio wave receiving circuit can be used.

  The second amplification circuit 34 further amplifies the reception signal input from the BPF 33 with a fixed gain. Therefore, in the present embodiment, the first amplification circuit 32 and the second amplification circuit 34 constitute a signal amplification unit that amplifies the reception signal.

  The envelope detection circuit 35 includes a rectifier (not shown) and a low-pass filter (LPF) (not shown). The envelope detection circuit 35 rectifies and filters the received signal input from the second amplifier circuit 34, and performs filtering. The envelope signal thus obtained is output to the AGC circuit 36 and the binarization circuit 37. Therefore, in the present embodiment, the envelope detection circuit 35 constitutes a detection unit that detects a received signal and outputs an envelope signal.

  The AGC circuit 36 outputs a signal for determining a gain when the first amplification circuit 32 amplifies the reception signal based on the envelope signal input from the envelope detection circuit 35.

  The binarization circuit 37 constitutes a comparison unit that compares the envelope signal input from the envelope detection circuit 35 with a reference voltage and outputs a binarized signal. Specifically, as shown in FIG. 4, it is composed of a binarization comparator, and one of the two input terminals is connected to the envelope detection circuit 35, and the other input terminal is VREF. The switching circuit 38 is connected. Then, the binarization circuit 37 is based on an envelope signal input from the envelope detection circuit 35 and a reference voltage (threshold value) having a predetermined voltage input from the VREF switching circuit 38, that is, a binarization signal, that is, a TCO signal. Is output.

  Specifically, the binarization circuit 37 uses a 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 sets the reference voltage. If it is lower, an L level (low level) signal having a voltage value lower than that of the H level signal is output to the TCO decoding unit 41 of 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 TCO decoding unit 41.

  The VREF switching circuit 38 constitutes a reference voltage setting unit that sets the reference voltage of the binarization circuit 37. Specifically, as shown in FIG. 4, the VREF switching circuit 38 according to the present embodiment generates reference voltages VREF1 to VREF4 from the power supply voltage VDD output from the constant voltage source 381, and converts the reference voltage into binary values. Output to the circuit 37. The VREF switching circuit 38 includes a constant voltage source 381, four resistors R1 to R4 disposed between the constant voltage source 381 and the ground GND, and between these four resistors R1 to R4 and R3 and the ground GND. And four switches SW1 to SW4 disposed between the binarization circuit 37 and a constant current source 382 disposed between the resistor R4 and the ground GND.

  Among these, each of the switches SW1 to SW4 is configured by an analog switch, the switch SW1 is binarized between the resistors R1 and R2 and the binarization circuit 37, and the switch SW2 is binarized between the resistors R2 and R3. Between the circuit 37, the switch SW3 is between the resistors R3 and R4 and the binarization circuit 37, and the switch SW4 is between the resistor R4 and the constant current source 382 and the binarization circuit 37. Each is arranged. Each of the switches SW1 to SW4 is independently connected to the decode circuit 39 via the selection lines SEL1 to SEL4 so that the on / off state is switched according to a signal input from the decode circuit 39. It is configured. Then, when any one of these switches SW1 to SW4 is turned on (conductive state) and the other switches are turned off (non-conductive state), the power supply voltage VDD output from the constant voltage source 381 is The voltage is changed by the current IS and the resistor R output from the constant current source 382, and the reference voltage VREF is input to the binarization circuit 37.

  Such a VREF switching circuit 38 outputs the highest reference voltage VREF1 to the binarization circuit 37 when only the switch SW1 is in the ON state. The VREF switching circuit 38 outputs the second highest reference voltage VREF2 when only the switch SW2 is in the on state, and the third highest voltage reference when only the switch SW3 is in the on state. When the voltage VREF3 is output and only the switch SW4 is in the ON state, the lowest reference voltage VREF4 is output.

  The decode circuit 39 is connected to the control circuit unit 4 to be described later via a serial communication line SL. The decode circuit 39 decodes the control signal input from the control circuit unit 4, and sets the on / off state of the switches SW1 to SW4 of the VREF switching circuit 38 based on the code included in the control signal. Is output to each of the selection lines SEL1 to SEL4, and a signal for setting the on / off state of each of the switches 334, 335, 344, and 345 of the band pass filter 33 is output.

[Configuration of control circuit section]
As described above, the control circuit unit 4 controls the operation of the receiving circuit unit 3 and outputs a control signal to the decoding circuit 39 of the receiving circuit unit 3. Specifically, the control unit 47 of the control circuit unit 4 performs serial communication through the decode circuit 39 and receives a control signal instructing switching of the tuning capacitor or switching of the bandpass filter 33 according to the received standard radio wave. It is transmitted at the start of reception of a PWRON signal that activates the circuit unit 3.

The control unit 47 outputs a control signal for switching the reference voltage VREF. Specifically, for example, the control unit 47 switches the reference voltage at a predetermined timing in the standard radio wave time code format, switches the reference voltage depending on the type of the standard radio wave to be received, or responds to the switching of the bandpass filter 33. Switch the reference voltage.
Therefore, the control unit 47 constitutes a reference voltage control unit that controls the VREF switching circuit 38 that is a reference voltage setting unit, and a bandwidth control unit that sets the bandwidth of the bandpass filter 33.

The control circuit unit 4 decodes the TCO signal input from the binarization circuit 37 and sets the time of the time counter 43 based on the time code generated by decoding. Furthermore, the control circuit unit 4 controls the display unit 5 to display the time of the time counter 43.
As shown in FIG. 1, the control circuit unit 4 includes a TCO decoding unit 41, a storage unit 42, a time counter 43, a drive circuit unit 46, and a control unit 47. Note that the reference signal output from the crystal resonator 48 is input to the control unit 47.
Accordingly, the time information displayed on the display unit 5 is corrected based on the decoded signal by the control circuit unit 4, specifically, the TCO decoding unit 41, the time counter 43, the drive circuit unit 46, and the control unit 47. The time correction means is configured.

The TCO decoding unit 41 decodes the TCO signal input from the binarization circuit 37 of the receiving circuit unit 3 and extracts a time code (TC, time data) having date information and time information included in the TCO signal. To do. Then, the TCO decoding unit 41 outputs the extracted TC to the control unit 47.
Specifically, the TCO decoding unit 41 recognizes the waveform of the TCO signal and measures the reception pulse duty with respect to a predetermined pulse width (for example, 1 Hz). The TC is recognized from the TCO signal based on the difference in the received pulse duty.

For example, in a standard radio wave (JJY) used in Japan, as shown in FIG. 5, a signal is output by AM modulation in which the amplitude ratio between a high level signal and a low level signal is 100: 10. That is, the ratio of the amplitude of the low level signal to the amplitude of the high level signal is 10%.
Further, as shown in FIG. 5A, the pulse duty is when the pulse width of the high level signal is 0.8 seconds with respect to the pulse width of 1 second (that is, when the duty is 80%). , “0” signal (0 signal) is recognized. Further, as shown in FIG. 5B, when the pulse width of the high level signal is 0.5 seconds (that is, when the duty is 50%) with respect to the pulse width of 1 second, “1”. (1 signal) is recognized. Furthermore, as shown in FIG. 5C, when the pulse width of the high level signal is 0.2 seconds (that is, when the duty is 20%) with respect to the pulse width of 1 second, “M”. Recognize signals (marker signals) and “P” signals (position marker signals). The TCO decoding unit 41 recognizes a predetermined TC from the recognized 1 signal, 0 signal, and M and P signals.

In the above description, TCY recognition in JJY has been exemplified. However, when the received standard radio wave is of another type, TC is recognized based on the duty corresponding to each radio wave.
For example, as shown in FIG. 6, in the standard radio wave (WWVB) in the United States of America, a signal is output by AM modulation with the ratio of the amplitude of the high level signal and the amplitude of the low level signal being 100: 14.
Further, as shown in FIGS. 6A to 6C, the pulse duty is set such that the pulse width of the high level signal is 0.8 seconds (the pulse width of the low level signal is 0.2 seconds), that is, the duty is 80%. 0 signal in some cases, pulse width of high level signal is 0.5 seconds (pulse width of low level signal is 0.5 seconds), that is, if duty is 50%, 1 signal, pulse width of high level signal is 0 .M and P signals are recognized when the pulse width of the low level signal is 0.8 seconds, that is, when the duty is 20%.

Further, in the standard radio wave (DCF 77) in Germany, as shown in FIG. 7, a signal is output by AM modulation in which the ratio of the amplitude of the high level signal and the amplitude of the low level signal is 100: 25.
Further, as shown in FIGS. 7A to 7C, the pulse duty is 0 signal when the pulse width of the low level signal is 0.1 second, that is, when the duty of the low level signal is 10%, Is recognized when the pulse width is 0.2 seconds, that is, when the duty of the low level signal is 20%.
Further, in the DCF 77, the M and P signals are not subjected to AM modulation, and when the high level signal continues for 1 second, the M and P signals are recognized.

Further, as shown in FIG. 8, in the standard radio wave (MSF) in the UK, a signal is output by AM modulation in which the ratio of the amplitude of the high level signal and the amplitude of the low level signal is 100: 0.
Further, as shown in FIGS. 8A to 8C, the pulse duty is 0 signal when the pulse width of the low level signal is 0.1 second, that is, when the duty of the low level signal is 10%, 1 signal when the pulse width of the low level signal is 0.2%, that is, when the duty of the low level signal is 20%, and P signal when the pulse width of the low level signal is 0.5 second, that is, when the duty of the low level signal is 50% Recognize

Then, in the time code format for each standard radio wave, time information is transmitted by using each of the signals 1, 0, M, and P.
For example, in the time code format of JJY, as shown in FIG. 9, one signal is transmitted every second, and one record is formed in 60 seconds. That is, one frame is 60-bit data. The data items also include current time information for minutes and hours, and calendar information such as the date of the current year from January 1, the year (the last two digits of the year), and the day of the week. The value of each item is configured by a combination of numerical values assigned every second, and ON / OFF of this combination is determined from the type of signal. Further, when the P signal and the M signal are continuously input, that is, when the signal having a high level signal pulse width of 0.2 seconds is continuously input, the timing of the second signal is 0 second position. It becomes. Therefore, minute synchronization can be recognized by detecting two consecutive 0.2 second signals.
Although the other standard radio waves are not shown, time code formats are respectively defined.

  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. Such a storage unit 42 is set when the radio-controlled timepiece 1 is manufactured, and stores a reference voltage setting table 421 in which the set value of the reference voltage VREF in the VREF switching circuit 38 is stored as shown in FIG. .

As shown in FIG. 10, the reference voltage setting table 421 is set according to the conditions of the standard radio wave type, the bandwidth of the bandpass filter 33, and the timing.
As the types of standard radio waves, for example, four types of JJY, WWVB, DCF77, and MSF are set.
As the bandwidth of the bandpass filter 33, a first bandwidth WB1 and a second bandwidth WB2 wider than the first bandwidth WB1 are set. Here, the first bandwidth WB1 is, for example, 5 Hz, and the second bandwidth WB2 is, for example, 10 Hz.

As timing, a timing for acquiring a marker and a timing for acquiring a signal are set.
The timing for acquiring the marker is the timing for acquiring the 0 second position in the time code format of each standard radio wave. Specifically, there are timing for performing minute synchronization immediately after the start of reception, and timing for confirming the 0 second position at 1 minute intervals when time information is acquired after minute synchronization. Here, for confirmation of the 0 second position, two marker signals of a P signal (position marker) transmitted at a timing of 59 seconds and an M signal (marker) transmitted at a timing of 0 seconds are continuously received. Can be confirmed.
On the other hand, the timing for acquiring a signal is other than the timing for acquiring the marker in the time code format of each standard radio wave. Specifically, it is other than the timing for acquiring the marker when time information is acquired after minute synchronization. For example, the confirmation of the marker at 1-minute intervals may be performed by receiving signals of 59 seconds and 0 seconds. Therefore, the timing for acquiring signals other than the marker is a signal of 1 second to 58 seconds in the standard time code format. It is the timing to receive.

The reference voltage setting table 421 is set under the above conditions. For example, as shown in FIG. 10, when the standard radio wave is JJY, each reference voltage is set as follows.
That is, the reference voltage VREF4 is set when the marker is acquired with the first bandwidth, and is set with the reference voltage VREF1 when the time code is acquired with the first bandwidth. Further, the reference voltage VREF3 is set when the marker is acquired with the second bandwidth, and the reference voltage VREF2 is set when the time code is acquired with the second bandwidth.
Here, the magnitude of each reference voltage is VREF1>VREF2>VREF3> VREF4. That is, in JJY, when the bandwidth of the bandpass filter 33 is the same, the reference voltage at the time code acquisition time is set higher than the reference voltage at the time of marker acquisition. That is, VREF1> VREF4 and VREF2> VREF3. As shown in FIG. 11, in JJY, the marker signals P and M have a smaller pulse width of the high level signal than the other 0 and 1 signals, and the signal level of the envelope signal (detection signal). This is because the reference voltage needs to be lowered.

On the other hand, when the bandwidth of the bandpass filter 33 is switched between wide and narrow at the same timing, the responsiveness of the detection signal is different, so the reference voltage is set as follows.
That is, when the bandwidth is switched to the first bandwidth, since the bandwidth is narrower than the second bandwidth, the response of the detection signal is also deteriorated.
For this reason, in a signal with a narrow pulse width of a high-level signal such as a marker, the signal level of the detection signal does not become too high because the time until it switches from low level to high level and then to low level again is short. Will return to low level. For this reason, in the case of the first bandwidth, the reference voltage VREF4 for acquiring the marker needs to be lower than the reference voltage VREF3 in the case of the second bandwidth.
Similarly, for signals other than markers, where the pulse width of the high level signal is as wide as 0.5 seconds or more, it takes a short time to switch to high level again after switching from high level to low level. The signal level of the detection signal also returns to the high level without being too low. For this reason, in the case of the first bandwidth, the reference voltage VREF1 for detecting the signal needs to be higher than the reference voltage VREF2 in the case of the second bandwidth.

  However, in the present embodiment, since the band pass filter 33 is received with the second bandwidth WB2 fixed, when receiving JJY, the reference voltages VREF2 and VREF3 are switched and controlled. Processing when the bandwidth of the bandpass filter 33 is switched will be described in the second embodiment.

The time counter 43 counts time (internal time) based on the reference signal output from the crystal resonator 48. 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 from an oscillation circuit (not shown) in the control unit 47 to which the crystal unit 48 is connected, the second counter loops the signal at 60 counts, that is, 60 seconds. It is. The minute counter counts 1 when the 1 Hz reference signal is multiplied 60 times, and loops at 60 counts, that is, 60 minutes. The hour counter counts 1 when the 1 Hz reference signal is coefficiented 3600 times, and counts 24 times, that is, a loop that loops in 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 such that every time the minute counter counts 60, a signal is output from the minute counter to the hour counter and the hour counter is counted up.

  The drive circuit unit 46 controls the display state of the display unit 5 based on the time display control signal output from the control unit 47 and controls the display unit 5 to display the time. For example, when the display unit 5 has a liquid crystal panel and displays the time on the liquid crystal panel, the drive circuit unit 46 controls the liquid crystal panel based on the time display control signal and displays the time on the liquid crystal panel. To control. When the display unit 5 has a dial and a pointer, the drive circuit unit 46 outputs a pulse signal to the stepping motor that drives the pointer, and controls the pointer to move by the driving force of the stepping motor. .

  The controller 47 is driven based on the drive frequency input from the crystal resonator 48 and performs various control processes. That is, the control unit 47 controls the correction of the count of the time counter 43 by outputting the TC input from the TCO decoding unit 41 to the time counter 43. Further, the control unit 47 outputs a time display control signal for displaying the time counted by the time counter 43 on the display unit 5 to the drive circuit unit 46.

  Note that, as described above, the control unit 47 and the decode circuit 39 are connected by the serial communication line SL, and the control signal is input to the decode circuit 39 via the serial communication line SL. As a result, a control signal for controlling voltage switching of the VREF switching circuit 38 can be output to the VREF switching circuit 38 via the decoding circuit 39. The control unit 47 outputs a signal for controlling the VREF switching circuit 38 based on the information in the reference voltage setting table 421 stored in the storage unit 42.

  Here, in the serial communication between the control unit 47 and the reception circuit unit 3, a two-line synchronous interface capable of bidirectional communication between the control unit 47 and the reception circuit unit 3 is used. Serial communication may be performed. In such a case, after the control signal is output from the control unit 47 to the reception circuit unit 3, the reception circuit unit 3 again transfers the received and recognized control signal to the control unit 47, and the control unit 47 outputs the control signal. By confirming the data difference between the control signal and the input control signal, serial communication with higher reliability can be performed.

[Operation of the radio-controlled clock]
Next, the time correction operation using the standard radio wave in the radio wave correction watch 1 as described above will be described.
FIG. 12 is a flowchart showing the time adjustment operation of the radio-controlled timepiece 1. The operation described in FIG. 12 is when JJY is received, and the reference voltage is switched when the marker is acquired and when the time code is acquired while the bandwidth of the bandpass filter 33 is fixed to the second bandwidth. Controlled.

  When the control unit 47 of the radio-controlled timepiece 1 recognizes that an operation signal indicating that the time adjustment is to be performed is input from the external operation member 6 or that a preset time has come, a PWRON signal is sent to the reception circuit unit 3. Is input to activate the receiving circuit unit 3 to start reception of the standard radio wave by the antenna 2 (step 1, hereinafter, step is abbreviated as “S”).

At this time, the control unit 47 stops moving the second hand via the drive circuit unit 46 so as not to affect reception by the antenna 2. Further, the control unit 47 sets the frequency of the tuning circuit 31 according to the standard radio wave received.
Note that the type of the standard radio wave to be received is set as the initial value of the standard radio wave received last time, but the user can also select the standard radio wave by operating the external operation member 6. For example, when the long wave standard radio wave (JJY) is selected, it is set to either 40 kHz (East Japan) or 60 kHz (West Japan). Specifically, when the user selects JJY (Eastern Japan) and JJY (West Japan), the control unit 47 sets the selected frequency, and if not selected, the previous reception is performed. Set to frequency. Further, the controller 47 sets 77.5 kHz for DCF77 and 60 kHz for WWVB and MSF.

Next, the control unit 47 sets the reference voltage of the VREF switching circuit 38 to the reference voltage VREF3 at the time of marker acquisition in the JJY second bandwidth (S2).
As shown in FIG. 11B, the reference voltage VREF3 is set to a voltage smaller than the reference voltage Vth for binarizing the envelope detection signal by the conventional binarization circuit 37. That is, the reference voltage Vth is set at the center position of the maximum amplitude of the detection signal, that is, the center position of the peak and the bottom, so that all signals 0, 1, M, and P can be binarized.
For this reason, as shown in FIG. 11C, the binarized signal binarized with the reference voltage Vth has a large amount of deviation in the rising timing of each signal, making it difficult to ensure second synchronization. . In addition, the pulse width of the marker portion (M and P signals) is narrowed and may be mistakenly identified as noise or the like, or the marker cannot be acquired, and it is impossible to grasp the minute synchronization, that is, the 0 second position of the standard radio wave. There is.

On the other hand, in the present embodiment, in S2, the reference voltage of the VREF switching circuit 38 is set to VREF3 lower than Vth. For this reason, as shown in FIG. 11D, the shift amount of the rising timing of each signal is reduced, and second synchronization can be ensured. Also, the pulse width of the marker portion can be made close to the original signal, the marker can be accurately identified, and minute synchronization can be ensured.
However, in this case, as shown in FIG. 11D, 0 and 1 signals other than markers cannot be accurately determined.

When the marker reference voltage is set in S <b> 2, a TCO as shown in FIG. 11D is output from the binarization circuit 37.
The detection waveform is input to the AGC circuit 36, and the AGC voltage changes due to the change in the detection waveform. That is, when the voltage level of the detection waveform is low, the AGC voltage output from the AGC circuit 36 increases and the gain of the first amplifier circuit 32 increases. On the other hand, when the voltage level of the detection waveform is high, the AGC voltage output from the AGC circuit 36 decreases and the gain of the first amplifier circuit 32 decreases. Thereby, the gain of the first amplifier circuit 32 is automatically adjusted, and the level of the received signal is adjusted to an appropriate value.

Next, based on the TCO output from the binarization circuit 37 to the TCO decoding unit 41, the control unit 47 determines whether the marker has been acquired and minute synchronization has been established (S3).
Specifically, in Japanese standard radio waves (JJY), pulses rise at intervals of 1 second. Therefore, first, pulse rising at intervals of 1 second is detected to establish second synchronization. In Japanese standard radio waves, as shown in FIG. 9, the portion where the position marker (P) and the marker (M) are continuous is the time code start point (0-second position), and this continuous marker is acquired. If possible, minute synchronization can be established.

When it is determined that the marker has been acquired in S3, the control unit 47 sets the reference voltage of the VREF switching circuit 38 to the reference voltage VREF2 for acquiring the time code (S4). As shown in FIG. 11B, the reference voltage VREF2 is a voltage value higher than the reference voltages VREF3 and Vth. Therefore, the binarization circuit 37 outputs a TCO as shown in FIG.
Since the reference voltage VREF2 has a high voltage value, the signal of the marker portion may not be detected. On the other hand, each of the 0 and 1 signals has a high voltage value of the reference voltage VREF2, so that the signal width when binarized is shorter than the original signal, but the 0 and 1 signals are distinguished. I can. Therefore, the binarization circuit 37 outputs a TCO that can discriminate between 0 and 1 signals to the TCO decoding unit 41.

The control unit 47 acquires time information from the TCO decoding unit 41 (S5).
Then, the control unit 47 determines whether the received standard radio wave has reached 59 seconds (S6). Specifically, since the minute synchronization is established by acquiring the marker in S3, the fact that 59 seconds have passed since every minute is measured using the reference clock of the crystal oscillator 48 and the time counter 43, and 59 seconds. The determination of S6 is continued until the timing of.

When it is determined “Yes” in S6 at the timing of 59 seconds, the control unit 47 sets the reference voltage of the VREF switching circuit 38 to the marker reference voltage VREF3 (S7).
Next, the control unit 47 reconfirms the marker and determines whether minute synchronization has been established (S8).

When the minute synchronization is confirmed in S8, the control unit 47 sets the reference voltage of the VREF switching circuit 38 again to the reference voltage VREF2 for time code acquisition (S9).
And the control part 47 acquires time information from the TCO decoding part 41, and confirms the consistency (S10).
As a method for confirming consistency, for example, since the standard radio wave transmits time information at intervals of 1 minute, it is confirmed whether the time information acquired every minute is 1 minute intervals or not. A method of checking consistency by comparing the internal time measured by the time counter 43 with the reception time can be used.

In this embodiment, in S10, it is confirmed whether or not consistency is secured by acquiring four pieces of time information. That is, 1 minute is added to the first acquired time information, and it is determined whether or not it matches with the time information received in the next one minute. Then, 1 minute is added to the time information acquired this time, and it is determined whether or not it matches with the time information received in the next minute. Thus, until the time information acquired immediately before and the time information acquired this time match three times, it is determined as “No” in S10.
In this case, the control unit 47 determines whether or not the reception time (elapsed time from the start of reception) exceeds a preset time (for example, 5 minutes) (S11). As a result, it is possible to prevent wasteful power consumption by continuing the reception process for a long time, for example, in an environment where standard radio waves cannot be received.

If the reception time has not exceeded in S11, the control unit 47 returns to the time information acquisition process in S5, and repeats the processes in S5 to S11.
On the other hand, when it is determined that there is consistency by matching three times in S10, the control unit 47 ends the reception process (S12). Further, the time counter 43 is updated with the acquired time data, and the time display on the display unit 5 is corrected via the drive circuit unit 46 (S13).
Thereafter, the control unit 47 returns to normal hand movement processing (S14).

If the marker cannot be reconfirmed in S8 and minute synchronization cannot be established in S8, the control unit 47 determines whether the reception time is over as in S11 (S15).
When it is determined in S15 that the reception time has not exceeded, the control unit 47 returns to the marker acquisition confirmation process in S3 and continues the process.

  On the other hand, when the marker cannot be acquired in S3 and when the reception time exceeds the set time in S11 and 15, the control unit 47 ends the reception process (S16) and returns to the normal hand movement process (S14).

According to this embodiment, there are the following effects.
(1) In the present embodiment, the reference voltage to be compared with the envelope detection signal by the binarization circuit 37 is set by switching to a different voltage when the marker is acquired and when the time code is acquired. Yes. For this reason, it can set to the reference voltage suitable for acquiring the signal (P, M signal) showing a marker, and the signal (for example, 1 signal and 0 signal) showing time codes other than a marker, respectively. Therefore, each signal can be detected with higher accuracy than the case where the received signal is binarized with one type of reference voltage Vth, and the influence of noise can be reduced to improve the receiving performance.

(2) In addition, the marker acquisition reference voltage is set not only when synchronization is performed at the start of reception, but also when the marker is reconfirmed at the position of 0 seconds during reception by the processing of S6 to S8. Has been done. For this reason, even during the time code acquisition process, it can be confirmed whether minute synchronization is ensured at one-minute intervals, and the correct time code can be acquired accordingly, and reception performance can be improved.

(3) It is determined whether or not the marker has been acquired immediately after the start of reception (S3). If acquisition is not possible, reception is immediately terminated. For this reason, if you are moving to an area where standard radio waves cannot be received, or if you are moving to an environment where standard radio waves cannot be received such as in buildings or underground shopping streets, useless reception processing will not continue and useless Power consumption can be prevented.
Similarly, since reception has ended even when the reception time exceeds the set time, wasteful power consumption can be prevented in this respect as well.

[Second Embodiment]
Next, a radio-controlled timepiece according to a second embodiment of the present invention will be described with reference to the drawings.
The second embodiment is different from the first embodiment in that the bandwidth of the bandpass filter 33 is switched between the first bandwidth and the second bandwidth depending on whether or not the marker has been acquired. However, other basic processes are the same. The description of the same or similar parts as those in the first embodiment will be simplified or omitted.

In the radio-controlled timepiece of the second embodiment, as shown in FIG. 13, after the processing of S1, the bandwidth of the bandpass filter 33 is initialized to the second bandwidth (S20).
Here, the case where the bandwidth of the bandpass filter 33 is set to the first bandwidth and the case where the bandwidth is set to the second bandwidth wider than the first bandwidth are compared with each other as follows. There is a special feature.
In the case of the first bandwidth (for example, 5 Hz), there is an advantage that it is more resistant to noise than in the case of the second bandwidth (for example, 10 Hz), but the current consumption is large and the response of the detection signal is poor. There is a disadvantage of being vulnerable to change. On the other hand, the second bandwidth has the disadvantages that it is less susceptible to noise than the first bandwidth, but has the advantage of low current consumption, good detection signal response, and resistance to temperature changes. There is.

Therefore, in the second embodiment, the bandwidth of the bandpass filter 33 is set in consideration of these characteristics.
That is, at the start of reception, reception is performed by setting the second bandwidth with low current consumption. However, whether or not reception is possible is affected by ambient noise. For this reason, when a stable time code cannot be obtained from the reception circuit unit 3 with the second bandwidth, the reception is changed to the first bandwidth resistant to noise.
Here, when the bandwidth of the bandpass filter 33 is narrowed, the noise resistance is improved, but the level of the signal passing through the filter 33 is lowered, so that the gain of the AGC amplifier (first amplification circuit 32) is increased, Current consumption increases. For this reason, in the second embodiment, reduction of current consumption is emphasized, the initial bandwidth is set to the second bandwidth, and the first bandwidth is set only when affected by noise.

When the bandpass filter 33 is set to the second bandwidth, the control unit 47 sets the reference voltage VREF3 as the marker acquisition reference voltage in S2 and S7 as in the first embodiment, In S4 and S9, the reference voltage VREF2 is set as the time code acquisition reference voltage.
On the other hand, when it is determined in S3 that the marker cannot be acquired, the control unit 47 does not immediately terminate reception, but checks whether the current setting of the bandpass filter 33 is the first bandwidth (S21). ).

When it is determined as “No” in S21, the control unit 47 sets the bandpass filter 33 to the first bandwidth resistant to noise (S22). Thereafter, the process is restarted from the marker acquisition determination in S3.
Also, if it is determined as “Yes” in S21, that is, if the marker cannot be acquired even if the first bandwidth resistant to noise is set, the signal is acquired even if the reception process is continued further. Since there is a low possibility that it can be performed, the control unit 47 ends the reception process (S16).

When it is determined “No” in S15, the control unit 47 sets the bandpass filter 33 to the first bandwidth (S23), and restarts the process from the marker acquisition determination in S3.
In S23, if the bandpass filter 33 is already set to the first bandwidth, the bandwidth may be left as it is.
Here, when the marker cannot be reconfirmed in S8, it is a case where the marker can be acquired at least in S3, and the marker may not be temporarily confirmed. For this reason, the determination process as in S21 is not performed and the reception process is not immediately terminated, but after setting to the first bandwidth (S23), the marker acquisition determination in S3 is repeated again.

When the bandpass filter 33 is set to the first bandwidth, the control unit 47 sets the reference voltage VREF4 as the marker acquisition reference voltage in S2 and S7, as shown in FIG. In S4 and S9, the reference voltage VREF1 is set as the time code acquisition reference voltage.
That is, when the first bandwidth is set, there is an advantage that is stronger against noise than when the second bandwidth is set wider than that, but the responsiveness of the detection signal is poor, and as shown in FIG. The amount of change in the detection signal when changing to the high level and the low level becomes small. For this reason, there is a possibility that the signals 0, 1, P, and M cannot be detected with high accuracy if the reference voltages VREF2 and 3 in the case of the second bandwidth remain unchanged.

Therefore, in this embodiment, the reference voltage is set in accordance with the first bandwidth.
Here, the reference voltage VREF4 may be a voltage value lower than VREF3, and in this embodiment, the reference voltage VREF4 is set to a voltage lower by about 10% of the amplitude of the detection signal.
The reference voltage VREF1 may be a voltage value higher than VREF2, and in this embodiment, the reference voltage VREF1 is set to a voltage that is about 10% higher than the amplitude of the detection signal.
The optimum values of these reference voltages VREF1 to VREF4 vary depending on the specific value of the bandwidth set in the bandpass filter 33, the circuit configuration, the type of standard radio wave to be received, etc. What is necessary is just to set according to etc.

According to such 2nd Embodiment, the same effect as said 1st Embodiment can be show | played, and also the following effect is acquired.
At the start of reception, the bandpass filter 33 is set to the second bandwidth, so that the current consumption can be reduced and the response of the detection signal can be improved.
In addition, when the marker cannot be acquired, since the first bandwidth is more resistant to noise than the second bandwidth, the possibility that the marker can be acquired can be increased. For this reason, it is possible to improve the probability of successful reception of time information.

[Third Embodiment]
Next, a radio-controlled timepiece according to a third embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 15, the third embodiment is different from the first embodiment in that the bandwidth setting process (S30) is performed after the process of S1. In addition, since the bandwidth is set in S30, the reference voltages S2, S4, S7, and S9 are set according to each bandwidth as in the second embodiment.
Since other processes are the same as those in the first embodiment, description thereof is omitted.

In the bandwidth setting process (S30) of the present embodiment, the bandwidth is set according to the temperature.
That is, when receiving with the first bandwidth in consideration of noise resistance, etc., the center frequency of the bandpass filter 33 fluctuates in places where the temperature is high or low, and reception performance decreases (2.5 Hz). (3dB sensitivity degradation due to fluctuations).
Therefore, when a temperature sensor is incorporated in the radio-controlled timepiece 1 and the temperature measured by this temperature sensor is a temperature at which the center frequency of the bandpass filter 33 deviates by more than 2.5 Hz, the reception sensitivity is changed to the second bandwidth. The decline is suppressed.

Specifically, in S30, the temperature at the time of reception processing is detected, and the bandwidth is set according to the temperature. That is, the control unit 47 sets the first bandwidth if the measured temperature is within a preset temperature range, and sets the second bandwidth if the measured temperature is higher or lower than the temperature range. To do.
The temperature range may be set to an average temperature range in the case of being normally used, for example, about 15 to 25 degrees, but a specific range may be set as appropriate in implementation.

In S2, S4, S7, and S9, the control unit 47 performs processing by selecting a reference voltage corresponding to the bandwidth set in S30.
Also in such 3rd Embodiment, there can exist an effect similar to each said embodiment.
In addition, since the bandwidth of the bandpass filter 33 is set according to the ambient temperature, it is possible to prevent a decrease in reception sensitivity due to a temperature change and to improve the reception performance accordingly.

[Other Embodiments]
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, in the first to third embodiments, the processing flow in the case of receiving JJY has been described, but it can also be applied to the case of receiving other standard radio waves. In this case, the reference voltage may be set according to each standard radio wave.
For example, in the case of WWVB, as shown in FIG. 6, the signal is a 100: 14 AM-modulated signal, and the low-level signal with a small amplitude is 4% larger than JJY, which is a 100: 10 AM-modulated signal. Become. For this reason, the amplitude of the detection signal, that is, the change width when changing from the high level to the low level is smaller than JJY. That is, the level of the detection signal at the low level is higher in WWVB than in JJY. For this reason, it is preferable that the optimum value of the reference voltage for binarizing the detection signal of WWVB is about 2% higher than JJY.
Therefore, when the type of the standard radio wave to be received is WWVB, it is preferable to set the reference voltage about 2% higher than that of JJY when the marker is acquired and when the time code is acquired.

In the case of MSF, a signal is output by AM modulation of 100: 0, and the time code is a time code in which a high level portion with a large amplitude is 0.9 seconds, 0.8 seconds is “0”, “1”. And 0.5 seconds is a marker. Therefore, as shown in FIG. 16, the envelope detection signal is less likely to drop to a low level and is maintained at a high level as a whole.
For this reason, it is preferable to set the reference voltage higher than in JJY or the like in both cases of marker acquisition and time code acquisition. Specifically, in FIG. 16, the marker acquisition reference voltage VM1 is set to a level of about 50% of the maximum amplitude of the detection signal, and the time code acquisition reference voltage VM2 is the detection signal relative to VM1. What is necessary is just to set to the level about 10-20% of the maximum amplitude.

Further, in the case of DCF77, a signal is output with 100: 25 AM modulation, and the pulse width of the time code is the same as that of MSF. On the other hand, the marker is not AM-modulated as shown in FIG.
For this reason, when DCF77 is received, the reference voltage is set to the same value VD1 when the marker is acquired and when the time code is acquired. Since the DCF 77 has a high level period longer than that of the MSF, the reference voltage VD1 is preferably set to the same level as the VM2 or slightly higher than the VM2.

When the type of the standard radio wave is selected, the bandwidth of the bandpass filter 33 is set according to the type of the standard radio wave, and the reference voltage at the time of marker acquisition and time code acquisition is set to the selected bandwidth. You may make it set according to.
For example, the setting of the bandwidth in S30 of the third embodiment may be performed using the type of standard radio wave instead of performing the measurement temperature. In this case, when JJY or WWVB is received, the first bandwidth is set, and when DVF77 or MSF is received, the second bandwidth is set.
When the bandwidth of the band pass filter 33 is set to be narrow, the DCF 77 and MSF have poor response of rising of the detection signal and the amplitude of the detection waveform becomes small. For this reason, with a weak electric field strength, fluctuations occur in the detected waveform, and noise is included in the binarized output signal TCO of the receiving circuit unit 3. Therefore, if the bandwidth is widened to the second bandwidth, the change of the signal becomes steep, the amplitude of the detection waveform is increased, and the sensitivity can be improved.
DCF77 and MSF have short periods of 0.1 second and 0.2 seconds in which the amplitude of AM modulation is small in the time codes “0” and “1”. For this reason, when the bandwidth of the bandpass filter 33 is narrow (for example, 5 Hz), since the response of the detection signal is poor, the detection signal hardly changes between modulation 0% (MSF) and 25% (DCF 77). Accordingly, the reference voltages VD1 and VM2 at the time of DCF77 and MSF time code acquisition are 20% or more higher than the reference voltage VM1 at the time of MSF marker acquisition (for example, a level of about 50% of the maximum amplitude of the detection signal). It is preferable to do.
On the other hand, when the band-pass filter 33 has a wide bandwidth (for example, 10 Hz or more), since the response of the detection signal is good, the amplitude of the detection signal changes between modulation 0% (MSF) and 25% (DCF 77). Since the envelope detection is performed, when the amplitude changes, the position of the bottom of the detection signal also changes. Therefore, it is preferable that the reference voltage VD1 of the DCF 77 having a small amplitude change is higher than the reference voltage VM2 of the MSF. For example, VD1 is preferably about 12.5% higher than VM2.

  Further, when setting the bandwidth of the bandpass filter 33, the presence or absence of noise influence (condition 1) as in the second embodiment, the temperature change (condition 2) as in the third embodiment, or a modification example. Which condition to set among the types of standard radio waves described (condition 3) may be set according to the application of a device incorporating a receiving circuit. In this case, as in the second and third embodiments and the modified examples, only one condition of conditions 1 to 3 may be set, or a plurality of conditions may be set in combination.

  In addition, specific structures and procedures for implementing the present invention, such as specific configurations of the bandpass filter 33 and the VREF switching circuit 38, can be appropriately changed to other structures and the like within the scope of achieving the object of the present invention. .

  DESCRIPTION OF SYMBOLS 1 ... Radio wave correction clock, 2 ... Antenna, 3 ... Reception circuit part, 4 ... Control circuit part, 5 ... Display part, 6 ... External operation member, 31 ... Tuning circuit, 32 ... 1st amplifier circuit, 33 ... Band pass filter , 34 ... second amplifier circuit, 35 ... envelope detection circuit, 36 ... AGC circuit, 37 ... binarization circuit, 38 ... VREF switching circuit, 39 ... decode circuit, 41 ... TCO decode unit, 42 ... storage unit, 43 ... Time counter, 46 ... Drive circuit section, 47 ... Control section.

Claims (7)

Receiving means for receiving and demodulating standard radio waves;
Control means for controlling the receiving means;
A radio-controlled timepiece comprising time correction means for correcting time information based on a signal demodulated by the reception means,
The receiving means includes
A signal amplifying unit for amplifying the received signal of the standard radio wave;
A detector for detecting the amplified received signal and outputting an envelope signal;
A comparator that compares the envelope signal with a reference voltage and outputs a binarized signal;
A reference voltage setting unit that sets a voltage value of the reference voltage of the comparison unit to a marker acquisition voltage value or a time code acquisition voltage value that is a voltage value different from the marker acquisition voltage value;
The control means includes a reference voltage control unit that controls the reference voltage setting unit,
The reference voltage controller is
When acquiring a marker for acquiring a standard radio wave marker, the voltage value of the reference voltage is set to the marker acquisition voltage value,
When acquiring a time code for acquiring a time code of a standard radio wave, the voltage value of the reference voltage is set to the voltage value for time code acquisition.
A radio-controlled watch characterized by that. The radio-controlled timepiece according to claim 1,
The receiving means includes a bandpass filter capable of changing a bandwidth,
The control means includes a bandwidth control unit that sets the bandwidth of the bandpass filter,
The bandwidth controller is
According to the predetermined condition, set the bandwidth of the bandpass filter,
The reference voltage controller is
The radio wave correction timepiece, wherein the marker acquisition voltage value and the time code acquisition voltage value are set according to a set band-pass filter bandwidth. The radio-controlled timepiece according to claim 2,
The band pass filter is configured to be capable of switching a bandwidth between a first bandwidth and a second bandwidth wider than the first bandwidth,
The bandwidth controller is
At the start of reception, set the second bandwidth,
If the marker cannot be acquired or the time code cannot be acquired after starting reception, the radio wave correction timepiece is set to the first bandwidth. The radio-controlled timepiece according to claim 2,
Equipped with a temperature sensor to measure the temperature,
The band pass filter is configured to be capable of switching a bandwidth between a first bandwidth and a second bandwidth wider than the first bandwidth,
The bandwidth controller is
When the temperature measured by the temperature sensor is within a preset temperature range, set to the first bandwidth,
When the temperature measured by the temperature sensor is outside the temperature range, the radio frequency correction timepiece is set to the second bandwidth. The radio-controlled timepiece according to claim 2,
The band pass filter is configured to be capable of switching a bandwidth between a first bandwidth and a second bandwidth wider than the first bandwidth,
The bandwidth controller is
When the standard radio wave to be received is either the Japanese standard radio wave JJY or the American standard radio wave WWVB, set to the first bandwidth,
The radio-controlled timepiece according to claim 1, wherein when the standard radio wave to be received is either the German standard radio wave DCF77 or the British standard radio wave MSF, the second bandwidth is set. The radio-controlled timepiece according to any one of claims 1 to 5,
The receiving means is configured to receive a plurality of standard radio waves,
The reference voltage setting unit includes:
The marker acquisition voltage value and the time code acquisition voltage value can be set according to the type of standard radio wave,
The reference voltage controller is
When acquiring a marker for acquiring a standard radio wave marker, the voltage value of the reference voltage is set to the marker acquisition voltage value corresponding to the type of standard radio wave to be received,
When acquiring the time code to acquire the time code of the standard radio wave, the voltage value of the reference voltage is set to the time code acquisition voltage value corresponding to the type of the standard radio wave to be received.
A radio-controlled watch characterized by that. Receiving means for receiving and demodulating standard radio waves;
Control means for controlling the receiving means;
A method of controlling a radio-controlled timepiece comprising time correction means for correcting time information based on a signal demodulated by the reception means,
The receiving means includes
A signal amplifying unit for amplifying the received signal of the standard radio wave;
A detector for detecting the amplified received signal and outputting an envelope signal;
A comparator that compares the envelope signal with a reference voltage and outputs a binarized signal;
A reference voltage setting unit that sets a voltage value of the reference voltage of the comparison unit to a marker acquisition voltage value or a time code acquisition voltage value that is a voltage value different from the marker acquisition voltage value;
A step of setting a voltage value of the reference voltage to the marker acquisition voltage value when acquiring a marker for acquiring a standard radio wave marker;
When acquiring a time code for acquiring a time code of a standard radio wave, setting the voltage value of the reference voltage to the time code acquisition voltage value;
A method for controlling a radio-controlled timepiece, comprising:

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