JP4785259B2 - Time information receiver and radio-controlled clock - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a time information receiving apparatus capable of receiving signals of a plurality of frequencies including time information and a radio wave correction timepiece capable of correcting the time based on a signal including time information received by the time information receiving apparatus.
[0002]
[Prior art]
Currently, the longwave standard radio wave including time information operated by the Communications Research Laboratory of the Ministry of Posts and Telecommunications is transmitted at a transmission frequency of 40 kHz. From 2001, the operation of the longwave standard radio wave with a transmission frequency of 60 kHz is planned as the second station. ing. As a result, it is possible to receive a plurality of standard radio waves having different frequencies, increasing the chances of successful reception. However, most radio wave correction watches on the market have only a function of receiving a single frequency of 40 kHz.
[0003]
As a technique for selectively receiving a plurality of frequencies, an electronic frequency selective receiver using a superheterodyne receiver circuit is disclosed in Japanese Patent Laid-Open No. 6-125280, and Japanese Patent Laid-Open No. 6-214054 discloses. An electronic timepiece with a radio wave reception function using the electronic frequency selective receiver is disclosed. The superheterodyne receiving circuit mixes the received signal of a predetermined frequency and the local oscillation frequency signal output from the local oscillation circuit by a mixing circuit and outputs an intermediate frequency signal. Is detected by a demodulation circuit.
[0004]
[Problems to be solved by the invention]
The above-described superheterodyne receiver circuit requires a local oscillation circuit and a mixing circuit, so that the configuration is large and it is difficult to keep current consumption low. Therefore, for example, when a battery is used as the power source of the receiving circuit, there is a problem that the battery life is shortened and the frequency of replacing the battery is increased. This problem is common to radio-controlled timepieces that receive longwave standard radio waves using a superheterodyne receiver circuit and correct the time.
[0005]
Also, as a receiving circuit for a radio-controlled timepiece that requires high sensitivity, a superheterodyne receiving circuit has a low Q (quality factor) and is not suitable. In order to increase Q in a superheterodyne receiving circuit, for example, there is a method of performing frequency conversion twice, but there is a problem that the configuration becomes complicated. In addition, when used in an environment capable of receiving long-wave standard radio waves having a plurality of frequencies, it is necessary to select a better radio wave by selecting a tuning frequency and an intermediate frequency of the antenna.
[0006]
An object of the present invention is to save power of a time information receiving apparatus capable of receiving signals of a plurality of frequencies including time information and a radio wave correction timepiece capable of correcting the time based on a signal including time information received by the time information receiving apparatus. And miniaturization.
[0007]
[Means for Solving the Problems]
The time information receiving device according to the first aspect of the present invention includes a first antenna coil, a first capacitor connected in parallel to the first antenna coil, a second antenna coil, and the second antenna coil. It includes a second capacitor connected in parallel with the antenna coil, and a receiver for receiving the second frequency of the signal including a signal and the time information of the first frequency, including the time information, the first frequency wherein a first filter element have a frequency passband corresponding to the number, and the second filter element having a frequency pass band corresponding to the second frequency, and a filter circuit and are connected in parallel, Furthermore, the resonance frequency of the first resonance circuit composed of the first antenna coil and the first capacitor corresponds to the first frequency, and the second antenna coil, the second capacitor, From The resonance frequency of the formed second resonance circuit corresponds to the second frequency, one end of the first resonance circuit and one end of the second resonance circuit are set to the same potential, and the receiving unit is The received signal is output from the other end of the first resonance circuit and the other end of the second resonance circuit, and a first frequency including the time information from the signal output from the reception unit by the filter circuit. with configurations that signal and extracts a second frequency of a signal including the time information.
According to such a configuration, the local oscillation circuit and the mixing circuit can be eliminated, so that the time information receiving apparatus capable of receiving signals of two frequencies including time information can be reduced in size and power can be saved. Further, since the filter circuit has two filter elements connected in parallel, it is not necessary to select the pass band of the frequency alternatively, and an element for selecting the frequency extracted by the filter element can be eliminated. .
Furthermore, according to such a configuration, the receiving unit has two parallel resonance points, so that it is possible to receive both the first and second frequency signals including the time signal. Therefore, it is possible to receive the first and second frequency signals including the time information without specifying the frequency signal to be received. In addition, since signals are output from the other end of the first resonance circuit and the other end of the second resonance circuit, there are two output terminals of the receiving unit despite having two resonance circuits. Well, the configuration can be simplified.
[0011]
The time information receiving device may have a configuration in which the winding direction of the first antenna coil and the second antenna coil and the same. According to this configuration, the series resonance point caused by the first and second resonance circuits being connected in series can be separated from the two parallel resonance points, and the resonance impedance of the two parallel resonance points can be reduced. Decline can be prevented.
The time information receiving apparatus may be configured such that the first filter element and the second filter element are crystal filters. According to such a configuration, a very high Q can be obtained with a simple configuration as compared with a superheterodyne reception circuit, and the reception sensitivity can be improved.
[0012]
A radio-controlled timepiece according to a second aspect of the present invention detects the time information from a time information receiving device according to the first aspect of the present invention and a signal including the time information extracted by the time information receiving device. A time information detecting unit; a time measuring unit that measures the current time; and a time correcting unit that corrects the time measured by the time measuring unit based on the time information detected by the time information detecting unit. According to this configuration, it is possible to save power and reduce the size of the radio-controlled timepiece.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail based on an example shown in the drawings. In this example, a reception operation in a radio wave environment where both the above-described 40 kHz and 60 kHz long wave standard radio waves are transmitted will be described.
[0014]
FIG. 1 shows a first embodiment of the present invention. In FIG. 1, an antenna block 1 is a resonance circuit (tuning circuit) capable of selecting a tuning frequency. A resonance capacitor 1b connected in parallel with the antenna 1a to form a resonance circuit of 60 kHz, a capacitor 1c for setting the resonance frequency of the resonance circuit 1 to 40 kHz, and a reception frequency selection unit for controlling connection of the capacitor 1c to the resonance circuit 1 Switch element 1d. In this example, an analog switch that can be electrically controlled is used as the switch element 1d. When the frequency selection signal from the control circuit 8 to be described later is at the Vss level, the switch element 1d is in an open state, and when it is at the Vdd level, it is in a conductive state. It becomes.
[0015]
The voltage control amplifier circuit 2 amplifies the signal output from the antenna block 1.
[0016]
The filter circuit 3 includes a parallel circuit of a crystal resonator (crystal filter) 3a having a resonance frequency of 40 kHz and a crystal resonator (crystal filter) 3b having a resonance frequency of 60 kHz. A quartz filter generally has a very high Q (several thousands to several tens of thousands) and exhibits a sharp frequency discrimination characteristic, and therefore, only a signal that matches 40 kHz and 60 kHz can be passed.
[0017]
The amplifier circuit 4 amplifies the signal extracted by the filter circuit 3. The detector circuit 5 detects the signal amplified by the amplifier circuit 4. The rectifier circuit 6 rectifies the signal detected by the detector circuit 5 and voltage-control-amplifies a DC signal corresponding to the magnitude of the signal detected by the detector circuit 5, that is, the electric field strength of the long-wave standard signal received by the antenna block 1. The gain of the voltage controlled amplifier circuit 2 is adjusted according to the electric field strength of the long-wave standard signal that is output to the circuit 2 and received. Specifically, when the electric field strength of the long wave standard signal received by the antenna block 1 is weak, control is performed so that the gain of the voltage control amplification circuit 2 is increased. The decode circuit 7 receives the signal from the rectifier circuit 6, performs 0/1 determination from the signal level change, and converts it into a digital signal synchronized with the modulation timing of the long wave standard radio wave, that is, a time code signal. The control circuit 8 serving as a time correction unit reads the time code signal from the decode circuit 7, acquires time data (time information), and performs various controls. The time display unit 9 is an electronic timing type equipped with a pointer display position detection function. The time display unit 9 includes a time counter 9a that measures the current time based on the output of an internal oscillation circuit. Is displayed. The detection circuit 5, the rectifier circuit 6, the decode circuit 7 and the control circuit 8 constitute a time information detection unit.
[0018]
Next, the control circuit 8 for explaining the operation first sets the frequency selection signal to the Vss level and sets the resonance frequency of the antenna block 1 to 60 kHz. The antenna block 1 in which this setting has been made receives a 60 kHz long wave standard radio wave and outputs it as an electrical signal. The signal having a frequency of 60 kHz is amplified by the voltage control amplifier circuit 2, is input to the filter circuit 3, and passes through the crystal filter 3b. The processing so far is referred to as time information signal acquisition processing. The signal having a frequency of 60 kHz that has passed through the crystal filter 3 b is amplified by the amplifier circuit 4 and diode-detected by the detector circuit 5. The single-wave signal having a frequency of 60 kHz generated by the diode detection is smoothed by the rectifier circuit 6 and becomes a signal that matches the envelope of the long-wave standard radio wave. At this time, the rectifier circuit 6 outputs a DC signal corresponding to the magnitude of the input signal, adjusts the gain of the voltage controlled amplifier circuit 2 and determines the magnitude of the input signal, that is, the received intensity of the received long wave standard radio wave. This is transmitted to the control circuit 8. The signal smoothed by the rectifier circuit 6 and matched with the envelope of the long wave standard radio wave is decoded by the decode circuit 7 into a digital signal synchronized with the modulation timing of the long wave standard radio wave, that is, a time code signal. The control circuit 8 reads the time code signal from the decoding circuit 7, acquires time data (time information), compares the acquired time data with the time measured by the time counting unit 9a, and if they do not match, the time counting unit The time measured by 9a is corrected, and the display of the time display unit 9 is corrected. The processing so far is called time correction processing.
[0019]
If the DC signal indicating the received intensity of the received long wave standard radio wave does not reach a predetermined level, the control circuit 8 sets the frequency selection signal to the Vdd level and sets the resonance frequency of the antenna block 1 to 40 kHz. The antenna block 1 thus set receives a 40 kHz long wave standard radio wave and outputs it as an electrical signal. The signal having a frequency of 40 kHz is amplified by the voltage control amplifier circuit 2 and input to the filter circuit 3 and passes through the crystal filter 3a. Thereafter, time information signal acquisition processing and time correction processing similar to those described above are performed. In this example, the frequency of 60 kHz is first selected and then the frequency of 40 kHz is selected. However, this order can be changed as appropriate.
[0020]
As described above, since the filter circuit 3 is a multipath type, it is not necessary to switch the filter elements even when long-wave standard radio waves having different frequencies are received. Therefore, a switching element such as a switch necessary for filter switching, a filter switching control signal, and the like are not necessary, and the configuration and the signal can be simplified.
[0021]
In addition, since the switch element 1d that causes the antenna block 1 (reception unit) to receive a signal having a desired frequency from long-wave standard radio waves having different frequencies is provided, the long-wave standard radio wave to be received can be selected. Since the switch element 1d is controlled according to the electric field strength of the long wave standard radio wave received by the antenna block 1 (reception unit), if the electric field strength of the long wave standard radio wave received earlier is weak, the long wave received earlier It is possible to switch to receive a long wave standard radio wave having a frequency different from that of the standard radio wave, and the probability that time information can be received reliably is improved.
[0022]
In the above description, an analog switch is used as the reception frequency selection unit.
[0023]
Next, a second embodiment of the present invention will be described with reference to FIG. In the figure, the same components as those in FIG. The second embodiment is greatly different from the first embodiment in that the antenna block 10 can simultaneously receive signals of two frequencies, thereby providing the antenna block 10 with a switching element for frequency selection. This eliminates the need for a signal for controlling the switch element.
[0024]
In FIG. 2, an antenna block 10 is a tuning circuit having two parallel resonance points of 40 kHz and 60 kHz, an antenna coil 10a forming a 40 kHz resonance circuit, a resonance capacitor 10b, and an antenna coil 10c forming a 60 kHz resonance circuit. And one end of the two resonance circuits are connected to each other at the same potential (common), and the other ends of the two resonance circuits are connected to the voltage controlled amplifier circuit 2.
[0025]
FIG. 3 shows a main part of the antenna block 10, and a common core 1e is inserted in the antenna coil 10a and the antenna coil 10c so that the output becomes large.
[0026]
The antenna block 10 configured as described above is a tuning circuit having two parallel resonance points (a and c in FIG. 4) as shown in FIG. As shown in FIG. 4, the antenna block 10 has a series resonance point (b in FIG. 4) between two parallel resonance points. This is in the number and position of turns of the antenna coil, the winding direction of the antenna coil, etc. Due to the above, it approaches a in FIG. 4 or approaches c in FIG. If the series resonance point is extremely biased, the resonance impedance is lowered, leading to a deterioration in antenna characteristics. Thus, in this example, the series resonance point is prevented from becoming extremely close to the parallel resonance point by aligning the winding directions of the antenna coil 10a and the antenna coil 10c.
[0027]
Next, the operation will be described.
[0028]
When the antenna block 10 receives a 40 kHz long wave standard radio wave, an electrical signal of 40 kHz corresponding to the signal is output to the voltage controlled amplifier circuit 2. When the antenna block 10 receives a 60 kHz long wave standard radio wave, a 60 kHz electrical signal corresponding to the received signal is output to the voltage controlled amplifier circuit 2. The processing after the voltage control amplifier circuit 2 is the same as the time information signal acquisition processing and time correction processing of the first embodiment described above.
[0029]
As described above, in the second embodiment, the antenna block and the crystal filter are multipath type, so that it is not necessary to select a signal having a frequency to be received by the control circuit 8, and the configuration can be simplified. In an environment where any one of the long wave standard radio waves can be received, time data (time information) can be acquired. Therefore, in this case, the control circuit (software) that can be used in the radio-controlled timepiece that receives the long-wave standard radio wave of 40 kHz and corrects the time can be used without change, and the control circuit (software) can be shared. Can be planned.
[0030]
In addition, at the reception point where the electric field strengths of the two long wave standard radio waves of 40 kHz and 60 kHz are substantially equal, both radio waves are superimposed, and it is possible to obtain a stronger signal than when a single long wave standard radio wave is selected. Thus, the receiving sensitivity is effective.
[0031]
In each of the above embodiments, a time display unit using a pointer is adopted, but a digital display type time display unit may be used.
[0032]
【The invention's effect】
According to the present invention, in a time information receiving device capable of receiving signals of a plurality of frequencies including time information and a radio wave correction timepiece capable of correcting time based on a signal including time information received by the time information receiving device, local oscillation Circuits and mixing circuits can be eliminated, and the configuration can be simplified and power can be saved. In addition, since filter elements having passbands corresponding to each of a plurality of frequencies including time information are connected in parallel so that a plurality of frequencies including time information can pass simultaneously, in order to select a frequency that the filter passes Circuit elements and the like can be eliminated.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a block diagram showing another embodiment of the present invention.
FIG. 3 is a detailed view of a main part of FIG. 2;
4 is an explanatory diagram showing impedance characteristics of the antenna block 10 of FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Reception part 1d Frequency selection part 3a Filter element Crystal filter 3b Filter circuit 5, 6, 7, 8 Time information detection part 8 Time correction part 9a Timekeeping part 10a 1st antenna coil 10b 1st capacitor 10c 2nd antenna Coil 10d Second capacitor 10a, 10b First resonance circuit 10c, 10d Second resonance circuit

Claims (7)

A first antenna coil; a first capacitor connected in parallel to the first antenna coil; a second antenna coil; and a second capacitor connected in parallel to the second antenna coil. a receiving section for receiving the second frequency of the signal including a signal and the time information of the first frequency, including a time information,
Said first filter and the filter element, and a second filter element having a frequency pass band corresponding to the second frequency, the are connected in parallel with the first have a frequency pass band corresponding to the frequency Circuit and
Including ,
The resonance frequency of the first resonance circuit composed of the first antenna coil and the first capacitor corresponds to the first frequency,
The resonance frequency of the second resonance circuit composed of the second antenna coil and the second capacitor corresponds to the second frequency,
One end of the first resonance circuit and one end of the second resonance circuit are at the same potential,
The receiver outputs the received signal from the other end of the first resonance circuit and the other end of the second resonance circuit,
By the filter circuit, the time information receiving device and extracting a second frequency signals including a signal and the time information of a first frequency, including the time information from the signal which the receiver has output. The time information receiving apparatus according to claim 1 , wherein the winding directions of the first antenna coil and the second antenna coil are the same. The time information receiving apparatus according to claim 1 or 2 , wherein the first filter element and the second filter element are crystal filters. The signal which the receiver is outputted claims 1 to 3, characterized in that is amplified by a gain corresponding to the signal level of the extracted signal by the filter circuit further comprising an amplifier for input to the filter circuit The time information receiver according to any one of the above. Detection means for detecting and outputting the signal extracted by the filter circuit;
The signal which the receiver is outputted claims 1 to 3 for amplifying a gain corresponding to the signal level of the output signal of the detecting means, further comprising an amplifying portion for inputting to the filter circuit The time information receiver according to any one of the above.   The first frequency signal is a 40 KHz long wave standard radio signal, and the second frequency signal is a 60 KHz long wave standard radio signal.
  The time information receiving apparatus according to claim 1, wherein the time information receiving apparatus is a time information receiving apparatus. The time information receiving device according to any one of claims 1 to 6 ,
A time information detector that detects the time information from a signal including the time information extracted by the time information receiver ;
A timekeeping section that measures the current time ,
A time correcting unit that corrects the time measured by the time measuring unit based on the time information detected by the time information detecting unit ;
An electric wave correction watch characterized by including.

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