JPH07273705A - Method and device for reception - Google Patents

Abstract

PURPOSE:To reduce the power consumption by stopping the power supply from a power supply device to one reception circuit at the time of discriminating that the other reception circuit is in the reception state of a prescribed level or higher. CONSTITUTION:A comparison circuit cue performs such control that the reception signal of a first antenna 31 is supplied to a first RF reception system circuit 41 through an antenna changeover switch 33 and demodulated data outputted from a demodulating circuit 43 is supplied to a channel decoder 36 through a changeover switch 35. When only the antenna 31 is used to advance the reception processing in reception slot periods RX1, RX2..., the reception strength is gradually reduced. The antenna changeover switch 33 is switched in a reception level measurement period LM just before the reception slot period RX4, and a reception wave 2 is received when the intensity of the reception electric field of an antenna 32 is increased. The equipment is set or not set to the diversity reception state in accordance with the intensity of the reception electric field in this manner to reduce the power consumption.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving apparatus and a receiving method suitable for application to, for example, a wireless telephone apparatus called a portable telephone.

[0002]

2. Description of the Related Art Conventionally, the positions of wireless telephone devices such as portable telephones and automobile telephones are constantly changing.
The communication state with the base station fluctuates greatly, and it is equipped with multiple system receiving antennas to perform diversity reception,
There are some that enable stable reception. That is, as a configuration of a normal receiving apparatus of this type, as shown in FIG. 3, for example, a radio signal picked up by an antenna 1 is supplied to an RF (high frequency) receiving system circuit 2 to transmit a transmission signal in a predetermined frequency band. Reception processing is performed to obtain an intermediate frequency signal. Then, the intermediate frequency signal output from the RF receiving system circuit 2 is supplied to the intermediate frequency circuit (IF circuit) 3 to perform intermediate frequency processing such as amplification. Then, the processed intermediate frequency signal is supplied to the demodulation circuit 4, demodulation processing for demodulating and detecting according to the communication system is performed, and the detection signal is obtained at the output terminal 5.

In the case of a receiving apparatus having only one system of antennas as shown in FIG. 3, it becomes difficult to obtain a good reception signal when the reception state of the antenna 1 deteriorates. There is a receiving apparatus that is provided with a plurality of antennas as shown in FIG. 1 to perform diversity reception.

The receiving apparatus shown in FIG. 4 has a first antenna 1
Two antennas, that is, the first antenna 12 and the second antenna 12, are provided, and the reception signals of the antennas 11 and 12 are switched by the changeover switch 13 and selectively supplied to the RF reception system circuit 2. And R
The configuration from the F reception system circuit 2 to the demodulation circuit 4 is basically the same as that of the reception device of FIG. 3 which does not perform diversity reception. However, in the intermediate frequency circuit 3, the data of the received electric field strength RSSI can be output to the terminal 6 based on the level of the supplied intermediate frequency signal.

FIG. 5 shows the switching state of the antennas in the receiving apparatus configured as described above. For example, the timing of performing communication with the other party in this apparatus (which also performs reception and time division transmission) is shown in FIG. As shown in A, the reception level measurement period LM is set between the transmission period TX and the reception period RX,
Between the reception period RX and the transmission period TX, an idle period Id
Is set. Then, the first antenna 11
It is assumed that the received wave 1 when received at 1 is at the level shown in B of FIG. 5, and the received wave 2 when received at the second antenna 12 is at the level shown in C of FIG. And D in FIG.
Indicates an antenna changeover control signal. When the control signal is high level, the changeover switch 13 selects the first antenna 11, and when the control signal is low level, the changeover switch 13 selects the second antenna 12. .

When the reception level measurement period LM is reached, the antenna switching control signal is switched between high level and low level, and the RF reception circuit 2 receives the first antenna 11 and receives the second antenna 12. The processing is executed continuously. By doing so, the reception electric field strength RS obtained at the terminal 6 during the reception level measurement period LM
As shown in E of FIG. 5, the SI is obtained in order of the reception level of the first antenna 11 and the reception level of the second antenna 12. Therefore, the control circuit (not shown) of this receiving device can determine which of the two reception levels has the higher reception electric field strength, and the reception electric field strength is high in the reception period RX following the reception level measurement period LM. The antenna switching control signal is set so that the person who has judged (here, the received wave 1 by the first antenna 11) is received, and the changeover switch 1
Switch 3

By doing so, reception processing is performed using the antenna that can receive favorably in each reception period, and antenna diversity reception is performed in which the antennas of two systems are appropriately switched.

By the way, in the case of the antenna diversity reception, there is a disadvantage that the antenna of the other system cannot be switched to even if the reception electric field strength is lowered in each reception period RX. That is, as shown in FIG. 5, in the case of a radiotelephone system in which transmission and reception are performed in a time-division manner, voice data converted into digital data is transmitted, and the reception signal before demodulation is received in each reception slot period. If switching is performed in the middle of RX, the received data may be temporarily interrupted, and accurate demodulation of the received data may not be possible. Therefore, the antennas are not switched within each reception slot period RX.

However, there is a possibility that the received electric field strength will decrease even within each reception slot period, and there are cases where switching to the antenna of the other system allows better reception. In order to solve this inconvenience, a receiving method called a post-detection diversity method has been proposed in which two systems from the antenna to the demodulation circuit are prepared and a better one is selected from the demodulation data of the two systems. .

FIG. 6 is a diagram showing an example of a diversity type receiving apparatus after the detection. The signal received by the first antenna 11 is received by the first RF receiving circuit 14 to be an intermediate frequency signal. , And supplies this intermediate frequency signal to the first intermediate frequency circuit 15. Then, the intermediate frequency processing such as amplification is performed in the first intermediate frequency circuit 15, and the processed intermediate frequency signal is supplied to the first demodulation circuit 16. Then, the demodulated data detected by the demodulation circuit 16 is supplied to the changeover switch 20. Further, the signal received by the second antenna 12 is received and processed by the second RF reception system circuit 17 to form an intermediate frequency signal, and this intermediate frequency signal is supplied to the second intermediate frequency circuit 18. Then, the second intermediate frequency circuit 1
Intermediate frequency processing such as amplification is performed at 8 and the processed intermediate frequency signal is supplied to the second demodulation circuit 19. Then, the demodulated data detected by the demodulation circuit 19 is supplied to the changeover switch 20.

Further, the data of the received electric field strength RSSI of the signals obtained by the intermediate frequency circuits 15 and 18 is compared with the comparison circuit 21.
To determine which receiving system has the highest received field strength.
Then, the demodulation data of the system that is judged to have the higher received electric field strength is selected by the changeover switch 20, and the selected demodulation data is supplied from the terminal 22 to the reception signal processing circuit of the subsequent stage.

With this configuration, for example, as shown in FIG. 7, the received wave 1 (in the system by the signal received by the first antenna 11 during the reception slot period RX (see A in FIG. 7)) The electric field strength of B) of FIG. 7 is reduced, and the received wave 2 (FIG.
When the electric field strength of C) becomes stronger, the comparison circuit 21
When this is detected, the control signal of the changeover switch 20 is changed over as shown in D of FIG. 7, and the demodulated data obtained at the terminal 22 is changed over to another system.

In the case of the configuration in which the signals detected as described above are switched, even if the demodulation data is switched by the changeover switch 20, if the detection processing in each of the demodulation circuits 16 and 19 is performed in synchronization. , Received data is not interrupted.
Therefore, by adopting the diversity system after detection shown in FIG. 6, it is possible to switch the receiving system at all times and always select the best receiving state.

FIG. 8 is a diagram comparing the reception performances of the respective reception systems. The characteristic a when diversity is not used as in the configuration shown in FIG. 3 has the worst bit error rate and only the reception antenna is switched. It can be seen that the bit error rate is improved as the characteristic b of the antenna diversity system and the characteristic c of the diversity system after detection become.

[0015]

Therefore, in the case of a receiving device such as a portable telephone device for a wireless telephone system, it is most preferable from the viewpoint of receiving performance to employ the diversity system after detection. However, in the case of the diversity system after detection, it is necessary to always perform the reception processing and the demodulation processing by the two reception processing systems, which causes a disadvantage that the power consumption of the reception device becomes larger than that of the other methods. there were. In particular, in the case of a wireless telephone device that is compactly configured for portable use, since it is battery-powered, it is necessary to extend the continuous use time without replacing the battery, but the diversity method after detection is applied. If the reception processing is always performed by the circuits of two systems, the duration of the battery is shortened and the usability of the telephone device is deteriorated.

In view of the above point, the present invention has an object to reduce the power consumption of the receiving apparatus to which the diversity system after detection is applied.

[0017]

As shown in FIG. 1, for example, a receiving apparatus of the present invention includes a first antenna 31, a second antenna 32, and a first receiving unit connected to the first antenna. Circuits 41-43 and a second antenna connected to the second antenna
The receiving circuits 51 to 53, the power supply means 65 to each receiving circuit, and the discriminating means 63 for discriminating the receiving state received by each receiving circuit are provided, and the receiving states of both receiving circuits are compared by the discriminating means. , Based on the comparison result, either one of the first and second receiving circuits 41-43 or 51-51.
In the receiving device that selects and outputs the output of 53, when the determining unit determines that one of the receiving circuits 41 to 43 or 51 to 53 is in the receiving state of a predetermined level or higher, the receiving unit receives the other from the power supply unit. Circuits 51-53 or 41-4
The power supply to No. 3 is stopped.

In this case, the second antenna is replaced by the first antenna.
It is possible to connect to the first receiving circuit by switching to the antenna.

Further, in each case, the discriminating means discriminates the receiving state of each receiving circuit from the received electric field strength.

According to the receiving method of the present invention, the radio signal picked up by the first antenna is received and processed to obtain the first received signal, and the radio signal picked up by the second antenna is processed and received. Of the received signal, comparing the state of each received signal to determine the one that was successfully received, while outputting one of the received signals that was determined to be successfully received out of any of the received signals, When it is detected in the above determination that the reception signal that has been successfully received is in the reception state of the predetermined level or higher, the reception processing of the other reception signal is stopped.

Further, in this case, the radio signal picked up by the first antenna and the radio signal picked up by the second antenna are switched so that reception processing can be performed.

Further, in each case, the received electric field strength is judged as the judgment of the reception state.

[0023]

According to the receiving apparatus of the present invention, when one receiving circuit selected as an output is in a receiving state of a predetermined level or more sufficient for receiving processing, the power supply to the other receiving circuit is stopped. Power consumption can be reduced. In this case, it is not necessary to switch to the other receiving circuit when one of the receiving circuits is in a receiving state of a predetermined level or more sufficient for receiving processing, so by stopping the power supply to the other receiving circuit, Diversity reception performance does not deteriorate.

In this case, the second antenna is replaced by the first antenna.
By connecting to the first receiving circuit by switching to the other antenna, antenna diversity becomes possible,
Depending on the reception state, it is possible to switch between antenna diversity and diversity after detection.

Further, in each case, the discriminating means discriminates the receiving state of each receiving circuit from the received electric field strength,
The receiving state of each receiving circuit can be easily determined.

Further, according to the receiving method of the present invention, when it is detected that the received signal which is successfully received is in the receiving state of the predetermined level or more, the receiving process of the other receiving signal is stopped, When it is not necessary to switch the reception processing system, the reception processing of the other reception signal is not performed, wasteful reception processing is not performed, and power consumption can be reduced accordingly.

Further, in this case, since the radio signal picked up by the first antenna and the radio signal picked up by the second antenna are switched so that the reception processing can be performed, antenna diversity becomes possible. The reception performance can be improved.

Further, since the receiving state is judged from the received electric field strength, the receiving state can be easily judged.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

This example is applied to a portable radiotelephone device in which digital data is wirelessly communicated with a base station, and is configured as shown in FIG. In FIG. 1, reference numerals 31 and 32 denote antennas, and the first antenna 3
Reference numeral 1 is an antenna for reception only, and second antenna 32 is an antenna for both transmission and reception. Then, the first antenna 31
The signal received by is supplied to the first fixed contact 33a of the antenna changeover switch 33.

Then, the signal received by the second antenna 32 is supplied to the movable contact 34m of the transmission / reception changeover switch 34. This transmission / reception changeover switch 34 has a movable contact 34m.
Is a switch that is switched under the control of a central control unit 60 described later in conjunction with switching between the transmission period and the reception period. The first fixed contact 34a on the receiving side of the changeover switch 34
To the second fixed contact 33b of the antenna changeover switch 33.
Connect to. Therefore, by switching the movable contact 33m of the antenna changeover switch 33, the signal received by the first antenna 31 and the signal received by the second antenna 32 (however, the transmission / reception changeover switch 34 is switched to the first fixed contact 34a side). You need to know that) and can be selected.
The switching of the antenna changeover switch 33 is performed under the control of the comparison circuit 63 described later.

Then, the signal obtained at the movable contact 33m of the antenna changeover switch 33 is supplied to the first RF (high frequency) reception system circuit 41 and is transmitted in a predetermined frequency band from the base station as a transmission signal of the downlink channel. To be processed as an intermediate frequency signal. Further, the signal obtained at the first fixed contact 34a from which the signal received by the second antenna 32 is obtained is supplied to the second RF reception system circuit 51 to receive the predetermined frequency band transmitted from the base station. The signal is processed into an intermediate frequency signal. As a frequency to be received and processed by each of the RF reception system circuits 41 and 51, for example, a transmission signal in the 800 MHz band or the 1.5 GHz band is used.
At 23, signals of the same frequency (channel) are received and processed. The reception frequency (reception channel) is set under the control of the central control device 60 described later.

Then, the first and second RF receiving circuit 4
The intermediate frequency signals output by 1 and 51 are supplied to the first and second intermediate frequency circuits (IF circuits) 42 and 52, respectively, and intermediate frequency processing such as amplification is performed. In this case, in each of the intermediate frequency circuits 42 and 52, the level of the supplied intermediate frequency signal (that is, received electric field strength: RSS
I) is detected and output.

The received signals subjected to the intermediate frequency processing by the intermediate frequency circuits 42 and 52 are supplied to the first and second demodulation circuits 43 and 53, respectively, and demodulated respectively to obtain demodulated data. Here, since the transmission signal is digital data, the demodulated detection signal is bit data. Then, each demodulation circuit 43, 5
The demodulated data demodulated in 3 is detected by the detection signal changeover switch 3
5 to the first fixed contact 35a and the second fixed contact 35b. The detection signal changeover switch 35 is a switch for selecting a good signal from the supplied two-system demodulation data, and the selection is performed by the control of the comparison circuit 63. The comparison circuit 63 receives the detection signal of the received electric field strength from each of the intermediate frequency circuits 42 and 52, discriminates the receiving system having the higher received electric field strength, and the one having the higher received electric field strength based on the discrimination result. The movable contact 35m of the changeover switch 35 is switched so as to output the demodulated data of.

Then, the demodulated data selected by the detection signal changeover switch 35 is supplied to the channel decoder 36. The channel decoder 36 is a circuit that extracts and decodes voice data and control data from the data transmitted according to the digital communication system to which the wireless telephone device is applied, and a microcomputer that controls the entire wireless telephone device. Decoding is performed under the control of the central control unit (CPU) 60, and the decoded control data is supplied to the central control unit 60.

Then, the audio data extracted from the received data is supplied to the audio decoder 37 to be decoded according to the communication system, and the decoded digital audio data is converted into an analog audio signal. The converted analog voice signal is output as voice from the speaker 38.

In FIG. 1, reference numeral 71 denotes a microphone,
The voice picked up by the microphone 71 is supplied to the voice encoder 72. The audio encoder 72 converts the supplied analog audio signal into digital audio data and encodes the converted digital audio data into audio data according to the communication system. Then, the encoded digital audio data is supplied to the channel encoder 73, and is encoded with the control data supplied from the central controller 60 into a channel according to the digital communication system to which the wireless telephone device is applied. Then, the encoded data is supplied to the modulation circuit 74 and digitally modulated according to the communication system. Then, the modulated signal is transmitted by the RF transmission circuit 75 to a predetermined frequency band (800 M
Hz band or 1,5 GHz band) transmission signal, and this transmission signal is the second fixed contact 34 b of the transmission / reception changeover switch 34.
Wirelessly transmitted from the second antenna 32 via.

The digital communication system to which the radio telephone apparatus of this example is applied is a time division multiple access system called TDMA, in which transmission timing and reception timing are set at different timings, and a transmission signal modulation system is set. For example, phase modulation such as π / 4 shift DQPSK modulation is applied.

Then, in the wireless telephone device of this example, a key 61 such as a numeral for inputting a dial number at the time of calling.
And a display unit 62 for displaying the operating state, dial number, etc.
And the operation information of the key 61 is supplied to the central control unit 60 so that a call operation can be performed and the central control unit 6
Various displays are performed on the display unit 62 based on the control of 0.

Further, the detection signal of the received electric field strength outputted from each of the intermediate frequency circuits 42 and 52 is changed over to the changeover switch 6
4 is supplied to the first and second fixed contacts 64a and 64b, and the detection signal of which the comparison circuit 63 determines that the received electric field strength is high is selected by the movable contact 64m. Then, the detection signal of the received electric field strength obtained at the movable contact 64m is
Supply to the central controller 60.

Further, the antenna changeover switch 33 is changed over according to each received electric field strength judged by the comparison circuit 63.

Further, in FIG. 1, reference numeral 65 denotes a power supply circuit, from which power supply for operation is supplied to each circuit in the apparatus. In FIG. 1, only the power supply path of the receiving system is shown,
The first receiving system circuit 41 via the power supply switch 66,
Power is supplied to the first intermediate frequency circuit 42 and the first demodulation circuit 43. Further, power is supplied to the second reception system circuit 51, the second intermediate frequency circuit 52, and the second demodulation circuit 53 via the power supply switch 67. This power supply switch 6
6, 67 are controlled by the central controller 60. Further, the channel decoder 36 and the audio decoder 37 are constantly supplied with power during the reception process.

Although not shown, the central controller 60
Of course, power is also supplied to other circuits such as.

Next, the operation of the telephone device of this example for receiving will be described with reference to FIG. In the case of this example,
The antenna diversity reception by switching the antenna changeover switch 33 and the diversity reception after detection by switching the detection signal changeover switch 35 are appropriately switched to perform reception processing, and the received electric field strength data output by each intermediate frequency circuit is converted into data. Make that choice accordingly.

First, as shown in FIG. 2A, each antenna 3
It is assumed that the received electric field strength changes when received at Nos. 1 and 32 (however, both received electric field strengths are not continuously detected). Here, the level shown by the solid line is the received electric field strength when the first antenna 31 receives it (referred to as received wave 1), and the level shown by the broken line is the received electric field strength (received wave strength 1 (received wave 1)). Wave 2).

Then, as shown in FIG. 2B, it is assumed that the slot periods RX1, RX2, RX3, ... For receiving are intermittently formed. Here, the reception slot period RX1
When, the reception electric field strength of the reception wave 1 in this period RX1 (actually, it is judged in the reception level measurement period immediately before that)
Is sufficiently higher than the reference first reception electric field strength Th1 by the comparison circuit 63. At this time, without receiving diversity, the control of the central control unit 60
Only the power supply switch 66 is connected to the reception slot period and the reception level measurement period immediately before it, and the first RF reception system circuit 41, the first intermediate frequency circuit 42, and the first demodulation circuit 4 are connected.
3 is supplied with power (C in FIG. 2 is the control state of the switch 66).

Then, the received signal of the first antenna 31 is supplied to the first RF receiving system circuit 41 via the antenna changeover switch 33, and the first RF receiving system circuit 41, the first intermediate frequency circuit 42, The comparison circuit 63 controls so that the first demodulation circuit 43 performs reception processing and the demodulation data output from the demodulation circuit 43 is supplied to the channel decoder 36 via the changeover switch 35. 2E shows the connection control state of the antenna changeover switch 33, which is connected to the first fixed contact 33a (that is, the first antenna 31 side) in the low level state, and the second fixed state in the high level state. It is connected to the contact 33b (that is, the second antenna 32 side). Further, F in FIG. 2 shows the connection state of the detection signal changeover switch 35, which is connected to the first fixed contact 35a (that is, the first demodulation circuit 43 side) in the low level state and the first state in the high level state. It is connected to the second fixed contact 35b (that is, the second demodulation circuit 53 side).

Then, in this way, the first antenna 3
Each receive slot period RX1, RX2 ...
The reception field strength gradually decreases and the reception field strength detected during reception in the reception slot period RX3 is the reference first reception field strength Th1.
Is detected.

At this time, in the reception level measurement period LM immediately before the next reception slot period RX4, as shown in E of FIG. 2, the antenna changeover switch 33 is switched alternately, and the reception waves of both antennas 31 and 32 are changed. The comparison circuit 63 detects the received electric field strength in the first intermediate frequency circuit 42. Then, at this time, it is detected that the received electric field strength of the received wave 2 is higher, and during the reception slot period RX4, the antenna changeover switch 33 is switched to the second antenna 32 side, and the received wave by the second antenna 32 is received. 2 is received and processed.

Also in the reception level measurement period LM immediately before the next reception slot period RX5, the antenna changeover switch 33 is switched alternately, and the reception waves of the antennas 31 and 32 are received by the first intermediate frequency circuit 42. The comparison circuit 63 detects the electric field strength. At this time, it is detected that the received electric field strength of the received wave 1 is higher, and in the reception slot period RX5, the antenna changeover switch 33 is switched to the first antenna 31 side, and the received wave 1 by the first antenna 31 is received. Is received and processed.

Up to this point, since the diversity reception is not performed at all or the antenna diversity reception is performed, the power supply switch 67 is kept in the open state, and the second RF signal is received even during the reception slot period. Receiver circuit 5
Reception processing is not performed in the first, second intermediate frequency circuit 52, and second demodulation circuit 53.

However, in the reception electric field strength measurement immediately before the next reception slot period RX6, even the reception electric field strength of the higher one is lower than the second reference level Th2 lower than the first reference level Th1. Is detected. When the received electric field strength is lower than the second reference level Th2, the detection is switched to diversity. That is, in the reception slot period RX6, as shown by C and D in FIG.
With 7 closed, power is supplied to both receiving circuit systems to operate them. Then, the antenna changeover switch 33 causes the first antenna 31 to be selected, and the first RF reception system circuit 41 causes the reception wave 1 received by the first antenna 31 to be processed. In the second RF receiving system circuit 51, the second
The reception wave 2 received by the antenna 32 is processed.

In the reception slot period RX6, the comparison circuit 63 always discriminates the reception electric field strengths of the two systems, and when the system having the high reception electric field strength is switched even in the middle of the reception slot period, the changeover switch is used. By switching 35, the demodulation data having the higher received electric field strength is supplied to the channel decoder 36. Next receive slot period R
Similarly, in X7, control by diversity after detection is performed.

Then, the higher received electric field strength is again the second
When the reference level Th2 is exceeded, the antenna diversity reception is switched to. When the first reference level Th1 is exceeded, the diversity reception is switched to.

As described above, by switching between the reception state in which no diversity is performed, the antenna diversity reception state, and the post-detection diversity reception state according to the received electric field strength, an appropriate reception process according to the reception level is performed. , Can receive the transmission signal satisfactorily. In this example, in the reception state without diversity and the antenna diversity reception state, only the power supply switch 66 is closed during the reception slot period, and the first RF reception system circuit 41, the intermediate frequency circuit 42, and the demodulation circuit. Since only the power is supplied to 43 and no power is supplied to the second RF receiving system circuit 51, the intermediate frequency circuit 52, and the demodulating circuit 53, only one receiving system operates. The power consumption required for reception can be reduced. Therefore, for example, when the wireless telephone device is a battery-operated device, the battery duration can be increased accordingly. In particular, when the reception condition is good, the battery life becomes long. As for the reception performance, since the diversity reception after detection having the best reception performance is performed when the reception state is poor, the same best reception performance as in the case where the diversity reception after constant detection is performed is secured.

It should be noted that the first reference level Th1 is set to the level of the received electric field necessary for making a decision to switch between the reception state in which diversity is not performed and the antenna diversity reception state. In addition, the second reference level Th2
Is set to the level of the received electric field necessary for determining whether to switch between the antenna diversity reception state and the post-detection diversity reception state.

Further, in the above-mentioned embodiment, the receiving state is judged by detecting the received electric field strength, but the receiving state may be judged by another method. For example, the reception state may be determined from the error rate of the received data, the SN ratio of the received signal, and the like.

Further, although the above-mentioned embodiment is applied to the receiving system of the wireless telephone device, it is needless to say that it is also applicable to the receiving device which performs other wireless communication.

[0059]

According to the receiving apparatus of the present invention, when one receiving circuit selected as an output is in a receiving state of a predetermined level or more sufficient for receiving processing, the power supply to the other receiving circuit is stopped. The power consumption can be reduced accordingly. In this case, it is not necessary to switch to the other receiving circuit when one of the receiving circuits is in a receiving state of a predetermined level or more sufficient for receiving processing, so by stopping the power supply to the other receiving circuit, Diversity reception performance does not deteriorate.

In this case, the second antenna is replaced by the first antenna.
By connecting to the first receiving circuit by switching to the other antenna, antenna diversity becomes possible,
It is possible to switch between antenna diversity and diversity after detection depending on the reception state, and it is possible to further improve reception performance. In this case, when performing antenna diversity, power need not be supplied to only the first receiving circuit, and power consumption can be reduced accordingly.

Further, in each case, the discriminating means discriminates the receiving state of each receiving circuit from the received electric field strength,
The receiving state of each receiving circuit can be easily determined.

Further, according to the receiving method of the present invention, when it is detected that the received signal which has been successfully received is in the receiving state of the predetermined level or more, the receiving process of the other received signal is stopped, When it is not necessary to switch the reception processing system, the reception processing of the other reception signal is not performed, wasteful reception processing is not performed, and power consumption can be reduced accordingly.

Further, in this case, the radio signal picked up by the first antenna and the radio signal picked up by the second antenna are switched so that the reception processing can be performed, which enables antenna diversity. The reception performance can be improved.

Further, since the receiving state is judged from the received electric field strength, the receiving state can be easily judged.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a wireless telephone device according to an embodiment of the present invention.

FIG. 2 is a timing diagram showing a control state according to an embodiment.

FIG. 3 is a configuration diagram showing an example of a receiving device that does not perform diversity.

FIG. 4 is a configuration diagram showing an example of a receiving device using antenna diversity.

FIG. 5 is a timing diagram showing an example of a reception state by antenna diversity.

FIG. 6 is a configuration diagram showing an example of a receiving device using diversity after detection.

FIG. 7 is a timing chart showing an example of a reception state by diversity after detection.

FIG. 8 is a characteristic diagram showing reception performance by each diversity system.

[Explanation of symbols]

 31 1st antenna 32 2nd antenna 33 Antenna changeover switch 35 Detection signal changeover switch 41 1st RF reception system circuit 42 1st intermediate frequency circuit 43 1st demodulation circuit 51 2nd RF reception system circuit 52 2 intermediate frequency circuit 53 second demodulation circuit 60 central control unit (CPU) 63 comparison circuit 65 power supply circuit 66, 67 power supply switch

Claims (6)

[Claims] 1. A first antenna, a second antenna,
A first receiving circuit connected to the first antenna, a second receiving circuit connected to the second antenna, a power supply means for supplying power to the receiving circuits, and receiving by the receiving circuits. A receiving unit for determining the receiving state, the receiving unit compares the receiving states of the two receiving circuits, and based on the comparison result, one of the first and second receiving circuits is selected. In the receiving device that selects and outputs the output of the receiving circuit, when the one of the receiving circuits determines that the one receiving circuit is in a receiving state of a predetermined level or more, the power supply unit sends the other receiving circuit to the other receiving circuit. A receiver that stops the power supply. 2. The receiving apparatus according to claim 1, wherein the second antenna is switched to the first antenna so that the second antenna can be connected to the first receiving circuit. 3. The receiving apparatus according to claim 1, wherein the discriminating means discriminates the receiving state of each receiving circuit from the received electric field strength. 4. A radio signal picked up by a first antenna is received and processed to obtain a first received signal, and a radio signal picked up by a second antenna is received and processed to obtain a second received signal, By comparing the states of each of the above received signals to determine which one was successfully received, one of the received signals that was determined to be successfully received is output, and at the same time the above determination is good. When it is detected that the reception signal that can be received in the above is in a reception state of a predetermined level or more, the reception process of the other reception signal is stopped. 5. The receiving method according to claim 4, wherein the radio signal picked up by the first antenna and the radio signal picked up by the second antenna are switched so that reception processing can be performed. 6. The receiving method according to claim 4, wherein the determination of the reception state is performed by determining the reception electric field strength.