JP2009097946A - Receiving device, radio-controlled clock, and receiving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power consumption of a radio-controlled clock, and to miniaturize, thin and lighten the clock. <P>SOLUTION: This radio-controlled clock 1 is equipped with an RF (Radio Frequency) processing part 10 for receiving a communication signal including time information transmitted by a digital communication system, and acquiring an IF (Intermediate Frequency) signal by mixing the received communication signal with a local oscillation signal; a baseband processing part 30 for converting the IF signal into a digital signal, demodulating it, and extracting the time information therefrom; an electric field intensity measuring part 26 for measuring the electric field intensity of the IF signal; and a control part 40 for instructing wholly to the RF processing part 10 and the baseband processing part 30. The control part 40 instructs start of acquisition of the IF signal and extraction of the time information, and when the electric field intensity of the IF signal measured by the electric field intensity measuring part 26 is weaker than a reference value of the electric field intensity capable of extracting the time information, the control part 40 instructs finish of acquisition of the IF signal and extraction of the time information. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a receiving device, a radio timepiece, and a receiving method for receiving a communication signal including time information.

  A radio timepiece that receives a time signal transmitted by radio waves and displays accurate time information is a standard radio wave of a long wave band transmitted from a ground base station or a very high frequency wave transmitted from a GPS (Global Positioning System) satellite. A method for receiving a time signal in a band is known. Furthermore, in recent years, as described in Patent Document 1 below, for the purpose of mobile communication, radio waves in the ultra-high frequency band that are modulated and transmitted by a CDMA (Code Division Multiple Access) method, which is one of digital communication methods, are transmitted. A timepiece device that receives a time signal included in the signal and obtains an accurate time has been proposed. Such ultra-short-wave radio waves are widely relayed from various relay stations, so compared to long-wave standard radio waves and radio waves from GPS satellites, in various destinations such as in buildings and underground Is known to be able to receive well. A clock device that receives a CDMA radio wave acquires an IF (Intermediate Frequency) signal from the received radio wave, demodulates a pilot channel signal from the acquired IF signal, and synchronizes with the base station. It is known that time information including GPS time, leap second, local offset, and daylight saving time information can be acquired by demodulating and decoding the sync channel signal.

JP 2000-321383 A

  By the way, since radio waves in the ultra-high frequency band are difficult to reach outside the line-of-sight range, time signals may not be received in a suburb far away from the relay station or in an underground shopping center with a complicated passage. However, in such an area where reception is not possible, the radio timepiece described above receives radio waves and repeats demodulation and decoding of pilot channel signals and sync channel signals at a predetermined frequency in order to obtain time information. A considerable amount of power was consumed each time. Therefore, it has been difficult to reduce the power consumption of the radio timepiece and the information processing apparatus including the timepiece function of the radio timepiece.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A receiving apparatus according to this application example receives a communication signal including time information transmitted by a digital communication method, and obtains an intermediate frequency signal by mixing the received communication signal and a local oscillation signal. A second processing unit for converting the acquired intermediate frequency signal into a digital signal, demodulating the converted digital signal to extract the time information, and an electric field strength of the acquired intermediate frequency signal. A measurement unit that measures, and an instruction unit that collectively instructs at least acquisition of the intermediate frequency signal in the first processing unit and extraction of the time information in the second processing unit, The acquisition of the intermediate frequency signal and the start of extraction of the time information are instructed, and the electric field strength of the intermediate frequency signal measured by the measurement unit can extract the time information. Is smaller than the reference value of the field strength is characterized by instructing the end of the extraction of acquisition and the time information of the intermediate frequency signal.

  According to such a configuration, when the electric field strength of the intermediate frequency signal acquired from the received communication signal is smaller than the reference value indicating the electric field strength of the intermediate frequency signal from which time information can be extracted, the received communication signal The process for acquiring the intermediate frequency signal and extracting the time information is not executed. Therefore, when the communication signal to be received is weak, the power consumed to acquire the intermediate frequency signal and extract the time information can be reduced, so that the power consumed by the receiving apparatus can be reduced.

[Application Example 2]
The receiving apparatus according to the application example may include a holding unit that holds the reference value.

[Application Example 3]
In the receiving device according to the application example described above, the instructing unit intermittently supplies power to the first processing unit and the second processing unit, thereby obtaining and acquiring the first processing unit. The extraction in the second processing unit may be collectively controlled.

[Application Example 4]
In the receiving device according to the application example, the instruction unit is a case where the electric field strength of the intermediate frequency signal measured by the measurement unit is larger than a reference value of the electric field strength from which the time information can be extracted, And when the time information cannot be extracted from the acquired intermediate frequency signal, the acquisition of the intermediate frequency signal and the start of extraction of the time information are repeatedly instructed for a predetermined number of times until the time information can be extracted. In addition, when the electric field strength of the intermediate frequency signal becomes smaller than the reference value, it is preferable to instruct the end of acquisition of the intermediate frequency signal and extraction of the time information.

  According to such a configuration, when the electric field strength is larger than the reference value, extraction of time information from the acquired intermediate frequency signal is repeated, and when the electric field strength becomes smaller than the reference value, the intermediate frequency signal Since the acquisition of time and the extraction of time information are completed, the possibility that time information can be acquired is improved, and the power consumed by the receiving apparatus can be further reduced.

[Application Example 5]
In the receiving apparatus according to the application example, the digital communication method may be a CDMA communication method.
[Application Example 6]
By applying the receiving device according to the application example described above to a radio timepiece, power consumption can be reduced, so that a battery for supplying power can be reduced in size, so that a radio timepiece that is reduced in size, thickness, and weight can be provided. .
[Application Example 7]
The receiving method according to this application example includes an acquisition step of receiving a communication signal including time information transmitted by a digital communication method, and acquiring an intermediate frequency signal by mixing the received communication signal and a local oscillation signal. Converting the acquired intermediate frequency signal into a digital signal, extracting the time information by demodulating the converted digital signal, measuring step measuring the electric field strength of the acquired intermediate frequency signal, A determination step for determining the magnitude of the reference value of the electric field strength from which the time information can be extracted and the electric field strength of the intermediate frequency signal, and the acquisition step and the extraction step are executed and acquired in the acquisition step If the determination step determines that the electric field strength of the intermediate frequency signal is smaller than the reference value, the execution of the acquisition step and the extraction step is terminated. The features.

  According to such a method, when the electric field strength of the intermediate frequency signal acquired from the received communication signal is smaller than the reference value indicating the electric field strength of the intermediate frequency signal from which time information can be extracted, the received communication signal The process for acquiring the intermediate frequency signal and extracting the time information from the acquired intermediate frequency signal is not executed. Therefore, when the communication signal to be received is weak, the power consumed to acquire the intermediate frequency signal and extract the time information can be reduced, so that the power consumed by the receiving apparatus can be reduced.

[Application Example 8]
In the reception method according to this application example, it is preferable that the measurement step and the determination step are executed in parallel with the acquisition step and the extraction step.
According to such a method, since the time required for the measurement process and the determination process is not added separately, the required time can be shortened.

  Hereinafter, an embodiment of a radio timepiece will be described with reference to the drawings as an embodiment of a receiving apparatus.

(Embodiment 1)
FIG. 1 is a block diagram illustrating a configuration of a radio timepiece 1 according to the first embodiment. The radio-controlled timepiece 1 is modulated by a CDMA (Code Division Multiple Access) method, which is one of digital communication methods, receives a radio wave in a very high frequency band for mobile communication transmitted from a base station, and includes a standard included in the radio wave. A receiving device that acquires time information of time is applied, and an accurate time based on the acquired standard time is displayed. The radio timepiece 1 includes an RF (Radio Frequency) processing unit 10, an electric field strength measurement unit 26, a baseband processing unit 30, a control unit 40, a power supply interrupting unit 50, a power supply unit 60, and a time information display unit. 70.

The RF processing unit 10 is a first processing unit that acquires an IF signal by mixing a communication signal and a local oscillation signal included in the received radio wave. The RF processing unit 10 includes a low noise amplifier 14, a frequency conversion unit 16, a local oscillation signal generation unit 18, an IF bandpass filter 20, an IF amplifier 22, and an IF signal output unit 24.
The communication signal input to the antenna 12 is amplified by the low noise amplifier 14, sent to the frequency conversion unit 16, and mixed with the local oscillation signal generated by the local oscillation signal generation unit 18. As a result, the time signal included in the communication signal is converted into an IF signal whose frequency is the difference from the frequency of the local oscillation signal (local oscillation frequency). Further, the IF signal is filtered by the IF bandpass filter 20, amplified by the IF amplifier 22, and then output from the IF signal output unit 24. The RF processing unit 10 performs the above processing according to the power supplied from the power supply unit 60. That is, when the power is supplied from the power supply unit 60, the RF processing unit 10 executes the above-described process, and when the power supplied from the power supply unit 60 is stopped, the RF processing unit 10 is described above. Pauses processing execution.

The electric field strength measurement unit 26 measures the electric field strength of the IF signal output from the IF signal output unit 24 based on an instruction from the control unit 40, and sends the measurement value to the control unit 40.
The baseband processing unit 30 is a second processing unit that converts the IF signal output from the IF signal output unit 24 into a digital signal, and demodulates the digital signal to extract time information. The baseband processing unit 30 includes a baseband demodulation unit 32, a time information extraction unit 34, and a time information output unit 36.
The baseband demodulator 32 performs A / D conversion of the IF signal into a digital signal, and then performs CDMA demodulation processing on two digital signals (I signal and Q signal) that are orthogonal in phase to obtain time information. Decrypt data that contains. The time information extraction unit 34 first acquires a pilot channel signal from the decoded data, and then demodulates a sync channel signal used to notify time information, system setting information, and the like based on the acquired pilot channel signal. Then, information on time is extracted from the demodulated sync channel signal. Information on the extracted time is output from the time information output unit 36 and displayed on the time information display unit 70. In the first embodiment, the time information display unit 70 can employ a liquid crystal panel that displays as a digital clock or a movement that displays as an analog clock.

Note that, similarly to the RF processing unit 10, the baseband processing unit 30 executes the above processing according to the power supplied from the power supply unit 60. That is, when power is supplied from the power supply unit 60, the baseband processing unit 30 executes the above-described processing. When the power supplied from the power supply unit 60 is suspended, the baseband processing unit 30 The execution of the above processing is paused.
The details of the process of receiving the communication signal including the time information transmitted by the CDMA method and acquiring the time information are not the gist of the present invention, and thus are omitted (for such a method, see, for example, 321383).

  The control unit 40 controls each functional unit of the radio timepiece 1. In the first embodiment, the control unit 40 includes a reference value holding unit 42, a power supply determination unit 44, and a power supply interruption control unit 46, and outputs an IF signal from the RF processing unit 10 and an electric field strength measurement unit 26. Instructing the measurement of the electric field strength by the method and the extraction of time information from the baseband processing unit 30. The power supply determination unit 44 compares the electric field strength of the IF signal measured by the electric field strength measurement unit 26 with the reference value held in the reference value holding unit 42, and determines whether or not the electric field strength exceeds the reference value. The determination is made and the determination result is sent to the power interruption control unit 46. In the first embodiment, the reference value may be a minimum electric field intensity necessary for acquiring time information from the IF signal, and is a value obtained by adding a predetermined margin to the minimum electric field intensity. Also good. Such a reference value may be determined by experiment, simulation, or the like. Based on the determination result, the power interruption control unit 46 instructs the power interruption unit 50 to interrupt the power supplied to the RF processing unit 10 and the baseband processing unit 30.

  The power interrupting unit 50 includes a switch 52 that collectively interrupts the power supplied to the RF processing unit 10 and the baseband processing unit 30, and is interrupted according to an instruction from the power interrupting control unit 46.

  Although not shown, each of the above-described functional units may be realized by an electric circuit, and includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a memory card, and the like. These hardware and software may be realized in cooperation. Further, at least a part of these functional units may be mounted on an integrated circuit.

Next, the flow of processing in which the radio timepiece 1 receives a communication signal, extracts time information, and displays the time information will be described with reference to FIG. FIGS. 3A and 3B are diagrams showing fluctuations in power consumption when this process is executed, and will be described with reference to FIGS. 3A and 3B. This process is executed in accordance with a predetermined timing, and when the process is started, first, the control unit 40 interrupts power supply to the RF processing unit 10 and the baseband processing unit 30. The unit 50 is instructed. As a result, the switch 52 is connected, predetermined power is supplied to the RF processing unit 10 and the baseband processing unit 30 (step S100), and the respective functions are executed. In the first embodiment, as shown in FIGS. 3A and 3B, power is supplied to the RF processing unit 10 and the baseband processing unit 30 at time T1, and the IF signal is measured from the RF processing unit 10 by measuring the electric field strength. Is output to the unit 26 and the baseband processing unit 30 (step S101). Then, the electric field strength measuring unit 26 measures the electric field strength of the output IF signal (step S102). Here, the time required for the electric field strength measurement is approximately 5 milliseconds.
The power supply determination unit 44 compares the measured electric field strength with the reference value (step S104), and determines whether the electric field strength is equal to or higher than the reference value (step S106). Here, if the electric field strength does not exceed the reference value (No in step S106), the process proceeds to step S116, and the connection of the connected switch 52 is released, whereby the RF processing unit 10 and the baseband processing unit 30 are connected. The power supply is stopped, and a series of processing ends. Then, it waits for the next reception opportunity. As a result, as shown in FIG. 3B, the power consumed in this processing is only the power consumed by the RF processing unit 10 and the baseband processing unit 30 for 5 milliseconds.

  On the other hand, when the electric field strength is equal to or higher than the reference value (Yes in step S106), power supply to the RF processing unit 10 and the baseband processing unit 30 is continued, and the baseband processing unit 30 acquires a pilot channel signal. (Step S108). Next, the baseband processing unit 30 acquires a sync channel signal (step S110). In the first embodiment, measurement of electric field strength and determination of power supply will be described in time series for easy explanation, but these processes are performed in parallel with the acquisition of the pilot channel signal in the baseband processing unit 30. Processed. Therefore, in parallel with the processing in the baseband processing unit 30, the measurement of the electric field strength and the determination of the power supply are performed. If the electric field strength does not exceed the reference value, the processing state in the baseband processing unit 30 is not concerned. An interrupt is generated, and power supply to the RF processing unit 10 and the baseband processing unit 30 is suspended.

In the first embodiment, the time required to acquire the IF signal by the RF processing unit 10 and the pilot channel signal by the baseband processing unit 30 is supplied with power as shown in FIG. It is about 26.7 milliseconds from time T1 to time T2. If the pilot channel signal cannot be acquired due to multipath or interference from other wireless stations, the pilot channel signal is attempted from T2 to T3, and the baseband processing unit 30 acquires the pilot channel signal. If not, the pilot channel signal is repeatedly acquired until T10. In this case, the predetermined power (P1) is consumed over a maximum of approximately 267 milliseconds.
The

  Next, the baseband processing unit 30 acquires time information from the sync channel signal (step S112). Subsequently, the acquired time information is displayed on the time information display unit 70 (step S114). Thereafter, the connection of the switch 52 is released, so that the power supply to the RF processing unit 10 and the baseband processing unit 30 is suspended (step S116), and a series of processing ends. Then, it waits for the next reception opportunity.

  With the above processing, the radio-controlled timepiece 1 processes the time required for determining whether or not the electric field strength of the IF signal acquired from the received radio wave exceeds the reference value without separately requiring the electric field strength of the IF signal. If the reference value exceeds the reference value, time information is acquired and output. On the other hand, if the reference value is not exceeded, power supply to the RF processing unit 10 and the baseband processing unit 30 is suspended. Therefore, when the electric field strength of the IF signal is so weak that time information cannot be acquired from the pilot channel signal or the sync channel signal, the processing in the baseband processing unit 30 can be omitted, and the pilot channel signal can be acquired. Since the repeated processing is not executed, the power consumed by the radio timepiece 1 can be reduced. Accordingly, since the battery capacity of the radio timepiece 1 can be reduced, the radio timepiece 1 can be reduced in size, thickness, and weight. In this embodiment, the acquisition of the pilot channel signal and the acquisition of the electric field strength are started at the same time. However, the acquisition of the electric field strength can be somewhat delayed. However, the longer the delay is, the less the effect of reducing power consumption because the timing of stopping the supply of power is delayed when the electric field strength of the IF signal is so weak that time information cannot be acquired.

(Embodiment 2)
Next, Embodiment 2 of the present invention will be described with reference to FIGS. 4 (a) and 4 (b). In the following description, the same parts as those already described are denoted by the same reference numerals and description thereof is omitted. In the first embodiment described above, the acquired IF signal is larger than the reference value of the electric field strength from which the time information can be extracted, and the pilot channel is changed from the IF signal due to the interference signal from the multipath or other radio stations. If the signal could not be acquired, an attempt was made to acquire the pilot channel signal again. In the second embodiment, when the acquisition is attempted again, the electric field strength of the acquired IF signal is acquired each time, and the electric field strength of the acquired IF signal is larger than a reference value of the electric field strength from which time information can be extracted. As shown in FIG. 4A, the acquisition of the sync channel signal from the IF signal is attempted 10 times at most. On the other hand, when the reception status of radio waves changes and the electric field strength of the acquired IF signal becomes smaller than the reference value of the electric field strength from which time information can be extracted, as shown in FIG. When the next IF signal is acquired, the connection of the switch 52 is released according to an instruction from the control unit 40, and the power supply to the RF processing unit 10 and the baseband processing unit 30 is terminated. FIG. 4B shows a case where the electric field strength of the acquired IF signal becomes smaller than the reference value of the electric field strength from which time information can be extracted at the stage when the second reception is attempted.
In the above-described second embodiment, in addition to the effects of the first embodiment, when the sync channel signal is acquired again from the IF signal, if the electric field strength suddenly deteriorates, the subsequent reception operation is terminated. The power consumed by the radio timepiece 1 can be further reduced.

(Embodiment 3)
Next, Embodiment 3 of the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing a configuration of the receiving module 5. The receiving module 5 includes an RF (Radio Frequency) processing unit 10, an electric field strength measurement unit 26, a baseband processing unit 30, a control unit 40, and a power interrupting unit 50 described in the first embodiment. It is configured with. The power supply unit 60 supplies power to the receiving module 5, but it is possible to assume a state included in the receiving module 5. The receiving module 5 may be in the form of a single chip like an integrated circuit, or may be in a state in which a plurality of electronic components are mounted on a substrate. In the third embodiment, the reception module 5 employs each function unit of the radio timepiece 1 described in the first embodiment, but is not limited thereto, and each function unit of the radio timepiece 1 described in the second embodiment. May be adopted. The reception module 5 is connected to the information processing device 90, and time information output from the time information output unit 36 of the reception module 5 is input to the time information input unit 95 of the information processing device 90. 90 refers to time information as necessary.

The information processing apparatus 90 assumes the following apparatuses and applications in the third embodiment, but is not limited to these. Any device and application may be used as long as the device acquires time information from the receiving module 5.
・ Timekeeping for recording reservation in recording device ・ Viewing time measurement in pay broadcast receiving device ・ Determining transaction execution time in electronic transaction device of securities such as stocks ・ Determining creation date and time of official document in document creation device ・ Incorporated in other devices In this way, by incorporating the receiving module 5 into the information processing apparatus 90, the information processing apparatus 90 can acquire accurate time information with low power consumption.

  Although Embodiments 1-3 of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments, and includes design changes and the like within a scope that does not depart from the gist of the present invention. It is. For example, the operation instruction to the RF processing unit 10 and the baseband processing unit 30 is controlled by sending a control signal to the RF processing unit 10 and the baseband processing unit 30 instead of the control by the intermittent power supply supplied to them. You may do it.

1 is a block diagram illustrating a configuration of a radio timepiece according to a first embodiment. 5 is a flowchart showing a flow of processing in which the radio timepiece according to the first embodiment receives a communication signal, extracts time information, and displays the time information. (A) And (b) is a figure which shows the fluctuation | variation of the power consumption of the radio-controlled timepiece which concerns on Embodiment 1. FIG. (A) And (b) is a figure which shows the fluctuation | variation of the power consumption of the radio-controlled timepiece which concerns on Embodiment 2. FIG. FIG. 6 is a block diagram illustrating a configuration of a receiving module according to a third embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Radio clock, 5 ... Reception module, 10 ... RF processing part, 12 ... Antenna, 14 ... Low noise amplifier, 16 ... Frequency conversion part, 18 ... Local oscillation signal generation part, 20 ... IF band pass filter, 22 ... IF amplifier , 24 ... IF signal output section, 26 ... Electric field strength measurement section, 30 ... Baseband processing section, 32 ... Baseband demodulation section, 34 ... Time information extraction section, 36 ... Time information output section, 40 ... Control section, 42 ... Reference value holding unit 44 ... Power supply determination unit 46 ... Power supply interruption control unit 50 ... Power supply interruption unit 52 ... Switch 60 ... Power supply unit 70 ... Time information display unit 90 ... Information processing device 95 ... Time information input part.

Claims (8)

A first processing unit that receives a communication signal including time information transmitted by a digital communication method and obtains an intermediate frequency signal by mixing the received communication signal and a local signal;
A second processing unit that converts the acquired intermediate frequency signal into a digital signal, demodulates the converted digital signal, and extracts the time information;
A measurement unit for measuring the electric field strength of the acquired intermediate frequency signal;
An instruction unit for collectively instructing at least acquisition of the intermediate frequency signal in the first processing unit and extraction of the time information in the second processing unit;
The instructing unit instructs the acquisition of the intermediate frequency signal and the start of extraction of the time information, and the electric field strength of the intermediate frequency signal measured by the measuring unit is a reference of electric field strength from which the time information can be extracted. When the value is smaller than the value, the receiving apparatus instructs to end the acquisition of the intermediate frequency signal and the extraction of the time information. The receiving device according to claim 1,
A receiving apparatus comprising: a holding unit that holds the reference value. The receiving device according to claim 1,
The instruction unit is configured to intermittently supply power to the first processing unit and the second processing unit, thereby obtaining the acquisition in the first processing unit and the second processing unit. A receiving apparatus that collectively controls extraction. The receiving apparatus according to any one of claims 1 to 3,
The indicating unit is a case where the electric field strength of the intermediate frequency signal measured by the measuring unit is larger than a reference value of the electric field strength from which the time information can be extracted, and from the acquired intermediate frequency signal, When the time information cannot be extracted, until the time information can be extracted, repeatedly instructing the acquisition of the intermediate frequency signal and the extraction of the time information for a predetermined number of times, and the electric field strength of the acquired intermediate frequency signal is A receiving apparatus that instructs to end acquisition of the intermediate frequency signal and extraction of the time information when the reference value is smaller than the reference value. The receiving apparatus according to any one of claims 1 to 4,
The digital communication system is a CDMA communication system. A radio timepiece that receives a communication signal including time information,
A radio timepiece comprising the receiving device according to claim 1. An acquisition step of acquiring an intermediate frequency signal by receiving a communication signal including time information transmitted by a digital communication method, and mixing the received communication signal and a local oscillation signal;
An extraction step of converting the acquired intermediate frequency signal into a digital signal, demodulating the converted digital signal and extracting the time information;
A measuring step of measuring the electric field strength of the acquired intermediate frequency signal;
A determination step of determining a magnitude of a reference value of the electric field strength from which the time information can be extracted and the electric field strength of the intermediate frequency signal,
When the acquisition step and the extraction step are performed, and it is determined that the electric field strength of the intermediate frequency signal acquired in the acquisition step is smaller than the reference value in the determination step, the acquisition step and the A receiving method, wherein execution of the extraction step is terminated. The receiving method according to claim 7,
The receiving method, wherein the measurement step and the determination step are executed in parallel with the acquisition step and the extraction step.

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