JP2002064393A - Receiving power control method and receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a receiver at low cost by providing an AGC control method capable of easily improving the dynamic range of the receiver in a mobile station receiver for radio communication system for performing different communication systems by switching the frequency band of a received signal. SOLUTION: This device has an AGC control part for controlling the output of control information to a switcher by inputting control information outputted from a control part, power information outputted from a power detecting part and AGC control information inputted from the outside and when the inputted power information is greater than specified or when an AGC control signal is inputted, control information opposite to the contents of a control signal outputted by the control part is outputted to the switcher. Then, the switching part is used as an AGC circuit having a prescribed attenuation quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving apparatus for performing reception by switching a band-pass filter according to a frequency band of a received signal, and more particularly to an improvement of a receiving apparatus of a narrow band digital communication system.

[0002]

2. Description of the Related Art One of the Japanese communication system standards will be described with reference to FIG. Narrowband digital communication system (SCPC / FDMA: Single Channel Pe), which is one of the communication system standards in Japan
r Carrier / Frequency Division Multiple Access (ARIB STD-T61) standard defines two communication systems. FIG. 4 is a schematic diagram for explaining this SCPC communication method. 41 is a base station, 500 is an operation area of the base station 41, 42 to 46 are mobile stations, and 501 to 504 are communication paths (wireless carriers).

[0003] The first communication method is a communication form including a base station and a plurality of mobile stations. For example, as shown in FIG. 4, a communication mode composed of a base station 41 and mobile stations 42, 45 and 46 existing in its operation area 500 is such a case.
This is a base zone system in which one base station 41 covers an operation area 500 of mobile stations 42, 45, and 46. The base station 41 is assigned, for example, uplink and downlink wireless carriers 501, 503, and 504 from the 400 MHz band or the 150 MHz band. The transmission wave of the base station is converted into a downstream wave (frequency band f1 in FIG. 4),
The transmission wave of the mobile station is called an upstream wave (frequency band f2 in FIG. 4). A wireless carrier that pairs such uplink and downlink
By using 501, 503, and 504, between the base station 41 and the mobile station 42 (allocated wireless carrier 501) or between the mobile station 46 and the mobile station 45 via the base station 41 (allocated wireless carrier 503 and allocated wireless carrier 504) is performed.

A second communication system is a communication system in which mobile stations directly communicate with each other without passing through a base station, and is a communication system called direct communication between mobile stations. For example, as shown in FIG. 4, the mobile station 43 and the mobile station 44 use the radio carrier (frequency f3 in FIG. 4) that is not used by the base station 41, and the mobile station 43 operates the base station 41, for example. This communication method is used when the mobile station 44 is outside the area 500 (at this time, it does not matter whether the mobile station 44 is in the operation area 500).

FIG. 3 is a block diagram showing an example of a configuration of a mobile station receiving apparatus used in the above communication system. Here, it is assumed that the frequency band F1 is allocated to the downstream wave and the frequency band F2 is allocated to the upstream wave. The uplink and downlink pairs of radio carriers are divided into a downlink frequency band f1 (where f1 is one of the downlink frequency bands F1) and an uplink wave frequency band f2 (where f2 is the uplink frequency band F2). 1), and the radio carrier for direct communication between mobile stations is used for the uplink and downlink co-frequency band f3.
(F3 is one of the upstream frequency bands F2). 1 is an input terminal, 2-1 is a first switch, 2-2 is a second switch, 3-1 and 3-2 are band-pass filters (BPF: Band-Pass F)
ilter, hereafter referred to as BPF), 4 is an amplifier, 5 is a mixer, 6
Is an intermediate frequency filter (IF filter), 7 is a demodulation unit, 8 is a frame processing unit, 9-1 and 9-2 are oscillators, 10 is a control unit, 11 is a power detector, and 12 is an output terminal.

The input terminal 1 is connected to the terminal a of the first switch 2-1. The terminal b of the first switch 2-1 has a BPF3 having a pass band (pass frequency band) of a downstream frequency band F1. -1
The terminal c of the first switch 2-1 is connected to the BPF 3-2 whose pass band is the frequency band F2 of the upstream wave. BPF3-1 is the second switch 2-2
BPF3-2 is connected to the terminal c of the second switch 2-2.
Connected to. The terminal a of the second switch 2-2 is connected to the amplifier 4, and the amplifier 4 is connected to the mixer 5. Mixer 5 is IF
The IF filter 6 is connected to the demodulator 7 and the power detector 11. The demodulation unit 7 is connected to the frame processing unit 8, and the frame processing unit 8 is connected to the output terminal 12. The power detector 11 is connected to the control unit 10. The control unit 10 is connected to switching control terminals of the first switch 2-1 and the second switch 2-2. The control unit 10 is also connected to an oscillator 9-1. The oscillator 9-1 is connected to the mixer 5, and the oscillator 9-2 is connected to the demodulation unit 7. In the initial setting of the receiving device, both the first switch 2-1 and the second switch 2-2 are connected to the terminal a and the terminal b.

In FIG. 3, a received signal of a downstream wave of the frequency band f1 of the radio carrier received by the antenna and given from the input terminal 1 is given to the BPF 3-1 via the first switch 2-1 and is transmitted to the BPF 3-1. After being limited, the signal is supplied to the amplifier 4 via the second switch 2-2, amplified and output. At this time, BPF
3-1 is a BPF that has the characteristic of passing signals in the frequency band F1
It is. The band-limited amplified signal is received by mixer 5
, And is mixed with a local signal (frequency: f1 ± IF, IF: intermediate frequency) output from the oscillator 9-1 and frequency-converted to an intermediate frequency. Then, the signal is supplied to the IF filter 6 to remove unnecessary frequency components, and is supplied to the demodulation unit 7. The demodulation unit 7 demodulates the signal input from the IF filter 6 by a required demodulation method using the local signal separately supplied from the oscillator 9-2 as a reference signal, and supplies the demodulated signal to the frame processing unit 8. In the frame processing unit 8, required reception processing is performed, and the received information is output to the output terminal 12. The received information output to the output terminal 12 is output to another circuit. For example, if the received information is audio information, an audio signal is reproduced and audio is output from a speaker.

[0008] A part of the received signal is branched at the output side of the IF filter 6 and supplied to the power detector 11. Power detector 11
Detects the power value of the input signal, and supplies the power information of the detected received signal to the control unit 10. The control unit 10 displays the given power information on an indicator or the like (not shown). The user looks at the power value information such as the indicator and, for example, when the mobile stations communicate with each other, the first communication method via the base station (mobile station-mobile station communication or mobile station-base station communication). Communication) or direct communication between mobile stations, which is the second communication method. When the mobile station performs communication with the base station (mobile station-mobile station communication or mobile station-base station communication) using the first communication method, the control unit 10 controls the first switch 2-1. And a control signal for connecting the terminal a of the second switch 2-2 to the terminal b. When the mobile station performs direct communication between mobile stations using the second communication method, the respective terminals a of the first switch 2-1 and the second switch 2-2 are connected to the terminal c. A control signal to be output is output. These control signals are supplied to control terminals of the first switch 2-1 and the second switch 2-2, respectively. The control unit 10 sets the frequency of the local signal output from the oscillator 9-1. Further, the control unit 10 has a function of autonomously controlling the power level for transmitting the upstream wave using the received power information of the downstream wave provided from the power detector 11 and a function of controlling the mobile station to operate in the operation area of the base station. The mobile station controls a function unique to a mobile station that determines whether the mobile station is inside (located) or outside the area (out of range). When the control unit 10 switches between the first communication method and the second communication method, a user operates the receiving device to cause the control unit 10 to perform a switching operation.

[0009]

The prior art receiving apparatus described above mainly uses the first communication method, that is, communication between a base station and a mobile station, or between a mobile station and a mobile station via a base station. Performs communication between stations. In such a base station communication system, for example, the output of the base station transmitter is 20 W, the base station antenna gain is 10 dBi, and the mobile station antenna gain (50 Ω system) is 4 dB.
i, assuming that the distance between the base station and the mobile station is 100 m and the depression angle loss of the base station antenna is 20 dB, the input power Pr1 of the mobile station receiving device due to free space propagation is approximately 3 μW, so that the system Each block of the station receiving apparatus is designed so that a required receiving performance can be obtained even when a signal of this power is supplied to the input terminal 1.

[0010] However, it is assumed that the second communication system, that is, the maximum reception input when performing direct communication between mobile stations without passing through a base station, is even larger than that of the base station communication system. For example, the output of the mobile station transmitter is 2 W,
Assuming that the mobile station antenna gain is 4 dBi and the distance between the mobile stations is d, the input power Pr2 of the mobile station receiver is about 5 at d = 100 m.
μW, but about 450 μW at d = 10 m (1 for 3 μW
50 times (22 dB)).

Therefore, in the direct communication between mobile stations, in order to guarantee the reception performance when the distance between the mobile stations is at least 10 m, compared with the mobile station receiving apparatus used in the above-mentioned base station communication system, it is necessary to secure the reception performance. A receiver with a wide dynamic range of more than dB is required, and AGC (A
However, there is a disadvantage that the cost and the mounting area increase due to an increase in components such as an auto gain control circuit. An object of the present invention is to eliminate the above-mentioned drawbacks, to realize an AGC control method capable of easily improving the dynamic range of a conventional receiving apparatus, and to realize an AGC control method even when mobile stations communicate with each other in a short distance. It is an object of the present invention to provide a receiving device capable of obtaining the receiving characteristics of the above.

[0012]

In order to achieve the above object, a reception power control method according to the present invention performs reception by switching a BPF according to a frequency band of a reception signal by a first switching means. In the receiving device, it corresponds to the received signal.
The connection is switched to a BPF other than the BPF, the signal is received, and the leakage power due to the disconnection of the first switching means is transmitted to the subsequent stage of the receiving device to control the gain of the high-power reception signal.

The receiving apparatus of the present invention comprises an AGC control unit and an AGC control unit.
An AGC control signal input terminal is provided in the control unit, and the AGC control unit includes a control signal given from the control unit for the first switch,
The connection of the first switch is controlled by an AGC control signal externally supplied from an AGC control signal input terminal and power information of a received signal supplied from a power detection unit.
That is, the AGC control unit determines whether the power value of the received signal is larger than a specified value or at least one of an external AGC control signal and the power information of the received signal supplied from the power detection unit. In the first method, control information for making the connection opposite to the connection of the first switch by the control signal given from the control unit is provided to the first switch. That is, the first switch functions as an AGC circuit having a predetermined amount of attenuation, thereby realizing an AGC control method capable of easily improving the dynamic range of the conventional receiving apparatus, and allowing the mobile stations to communicate with each other over a short distance. Even in such a case, a receiving device capable of obtaining a required receiving power is realized.

Further, the reception power control method of the present invention includes a plurality of band-pass filters having different pass bands, and selects and uses one of the plurality of band-pass filters according to a frequency band of an input received signal. A receiving device,
A first switch for connecting the input received signal to any one of the plurality of band-pass filters, and a second switch for connecting a band-pass filter corresponding to the frequency band of the input received signal and a subsequent stage of the receiving device. And a band-pass filter according to a frequency band of the received signal input by the second switch,
The first stage is connected to the subsequent stage, and the input signal is attenuated by disconnecting the first switch between the input received signal and the band-pass filter corresponding to the frequency band of the input received signal. Things. Further, the reception power of the input reception signal is detected, and when the detected reception power is equal to or more than the predetermined value, the connection of the first switch is set according to the frequency band of the input reception signal and the input reception signal. This disconnects the connection with the bandpass filter.

Further, the receiving apparatus of the present invention comprises a plurality of bandpass filters having different passbands, a switching means for connecting a received signal to a corresponding bandpass filter from the plurality of bandpass filters, In a receiving apparatus having power information detecting means for detecting a received signal power and control means for generating a control signal for controlling a switching means, a control signal generated by the control means and a received signal power detected by the power information detecting means When the received signal power is equal to or more than a predetermined value, the connection of the received signal is changed to a control signal for switching to another band-pass filter. Further, second control information for controlling the connection of the switching means is inputted, and when there is the second control information, the connection of the received signal is changed to a control signal for switching to another band-pass filter. Further, when there are two bandpass filters having different passbands, the two bandpass filters are switched alternately.

[0016] The receiving apparatus of the present invention also includes a plurality of band-pass filters having different pass bands, switching means for connecting a received signal to a corresponding band-pass filter from the plurality of band-pass filters, In a receiving apparatus having power information detecting means for detecting a received signal power and control means for generating a control signal for controlling a switching means, a control signal generated by the control means and a received signal power detected by the power information detecting means When the input received signal power is equal to or more than a predetermined value, an AGC control unit that controls the switching unit by changing the connection of the received signal to a control signal for switching to another band-pass filter, If the input received signal power is less than the predetermined value, the control signal generated by the control means is directly provided to the switching means, and the input received signal power is equal to or more than the predetermined value. In some cases, by providing a switching means to change the control signal for switching the connection of the received signal to another bandpass filter is configured to receive signal received. Further, the receiving device of the present invention includes input means for changing the connection of the bandpass filter, and when the switching instruction is given to the AGC control unit by the input means, control for switching the connection of the received signal to another bandpass filter. The received signal is received by changing the signal into a signal and providing the signal to the switching means.

The receiving apparatus of the present invention further connects a received signal to a plurality of band-pass filters having different pass bands and a corresponding band-pass filter from among the plurality of band-pass filters depending on a receiving band to be used. Switching means;
An amplifier for amplifying a reception signal band-limited by a band-pass filter, an oscillator for generating a local signal, a unit for demodulating the reception signal amplified using the local signal, and a unit for detecting power of the reception signal; First controlling the connection of the means
Receiving the first control information of the first control means and the power information of the power detection means to control the connection of the switching means. And second control means for outputting control information to be performed. In this receiving apparatus, the first
Inputting a first control signal of the output of the control means, comparing the output of the power detection means with a specified value to determine a magnitude (first condition), and a second control input from the other. The step of judging the presence or absence of a signal (second condition) includes, when at least one of the first condition and the second condition is satisfied, the connection information of the switching means represented by the input first control signal. Updating the content to switch to the connection of
And outputting the updated control information to the switching means.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to FIGS. However, the frequency band (F1, F2, f
The conditions of (1, f2, f3) are the same as in the case of the aforementioned prior art. FIG. 1 is a block diagram showing one embodiment of the configuration of a mobile station receiving device used in the communication system of the present invention. FIG. 2 is a flowchart for explaining an embodiment of the processing of the AGC control unit of the present invention. Components having the same or similar functions as those described above are denoted by the same reference numerals. In addition, the control unit 10 'is a control unit, and 13 is an AGC control unit.

The difference between the configurations shown in FIGS. 1 and 3 is that an AGC control unit 13 which is not shown in FIG. 3 in FIG. 1 is added, the control unit 10 is replaced with a control unit 10 ', and the output of the power detector 11 is changed. In addition to being connected to the control unit 10 ', it is also connected to the AGC control unit 13. Further, the control unit 10 'is connected to the switching control terminal of the second switch 2-2 and the oscillator 9-1. Unlike FIG. 3, the control unit 10' has a switching control terminal of the first switch 2-1. Not directly connected, AGC control unit
13 is connected to the switching control terminal of the first switch 2-1. And an input terminal 1 for applying an AGC control signal.
4 is connected to the AGC control unit 13. In the initial setting of the receiving device, both the first switch 2-1 and the second switch 2-2 are connected to the terminal a and the terminal b. The first switch 2-1 and the second switch 2-2 are, for example, a commercially available SPDT type GaAs switch MMIC (Monolithic Microwave Integrated Circuit)
Is used.

In FIG. 1, a received signal of a downstream wave of a frequency band f1 of a radio carrier received by an antenna and given from an input terminal 1 is given to a BPF 3-1 via a first switch 2-1 and is applied to a BPF 3-1. After being limited, the signal is supplied to the amplifier 4 via the second switch 2-2, amplified and output. At this time, BPF
3-1 is a BPF that has the characteristic of passing signals in the frequency band F1
It is. Below, the output terminal to which oscillator 9-1 and oscillator 9-2 are added
The flow of signal processing up to 12 is as described in FIG.

A part of the received signal is branched at the output side of the IF filter 6 and supplied to the power detector 11. Power detector 11
Detects the power value of the input signal, and the detected power information of the received signal is supplied to the control unit 10 'and the AGC control unit 13. When the mobile station performs communication with the base station, the control unit 10 ′ connects the terminal a of the first switch 2-1 and the terminal b of the second switch 2-2 to the terminal b. Outputs a control signal,
When the mobile station performs direct communication between mobile stations, the mobile station outputs a control signal for connecting each terminal a of the first switch 2-1 and the second switch 2-2 to the terminal c. . These control signals are provided to the control terminals of the first switch 2-1 and the second switch 2-2, respectively. However, the control terminal of the first switch 2-1 is provided via the AGC control unit 13. In addition, the control unit 10 'is provided with a function provided in the control unit 10 described in the related art, for example, a function of displaying given power information on an indicator or the like (not shown), a local signal of the output of the oscillator 9-1. A function of autonomously controlling the power level for transmitting the upstream wave by using the received power information of the downstream wave provided from the power detector 11, and a function of the mobile station for controlling the operation area of the base station. The mobile station controls a function unique to a mobile station that determines whether the mobile station is inside (located) or outside the area (out of range).

The control unit 10 'sets the frequency of the local signal output from the oscillator 9-1. When the input power information exceeds a specified level (for example, a value corresponding to the design value of the maximum allowable input of the receiving device (for example, 5 μW)), the AGC control unit 13 sends the The control signal applied to the control terminal of the first switch 2-1 is inverted. That is, the control unit 10 '
If the control information (control signal) output from is a “control signal for connecting the terminal a of the first switch 2-1 to the terminal b”, the information for connecting the terminal a and the terminal c is Output to the first switch 2-1. Conversely, when the control information output from the control unit 10 'is "a control signal for connecting the terminals a and c of the first switch 2-1", the terminal a is connected to the terminal b. The information to be output is output to the first switch 2-1.

Further, the AGC control unit 13 is controlled so that output information from the control unit 10 'is inverted by an AGC control signal supplied from the outside via the input terminal 14. The AGC control signal input from the input terminal 14 is performed, for example, when it is desired to test a transmission / reception state or when it is known that a transmission / reception partner is in the immediate vicinity. The AGC control signal is input, for example, as needed by a user using the receiving device.

An embodiment of the processing in the AGC control unit 13 will be described with reference to FIG. In step 201, the control unit 10 ′ receives a control signal, which is output control information provided to the first switch 2-1, and proceeds to step 202. In step 202, it is determined whether or not an AGC control signal has been input from the input terminal 14, and if there is an AGC control signal, the process branches to step 204,
If there is no AGC control signal, the process proceeds to step 203. In step 203, it is determined whether or not the power information (magnitude of the power value) given from the power detection unit 11 is equal to or higher than a specified level.
If it is less than the specified level, the process proceeds to step 205.

In step 204, the control information for the first switch 2-1 input in step 201 is inverted and updated, and the flow advances to step 205. Here, the inversion / update of the control information means, for example, that the control signal output by the control unit 10 'is
If it is a control signal for connecting the terminal a to the terminal c side in 2-1, the control signal is to be changed to a control signal for connecting the terminal a to the terminal b side. Conversely, if it is a control signal for connecting the terminal a of the first switch 2-1 to the terminal b,
This is to change to a control signal for connecting the terminal a to the terminal c. Finally, in step 205, the first switch 2-1
And outputs the control signal determined by the above processing to the first switch 2-1.

Considering the case where direct communication between mobile stations is performed, if a signal in the frequency band f3 of the wireless carrier (f3 is one of the frequency bands F2 of the upstream wave) is input to the input terminal 1, the conventional method is adopted. The first switch 2-1 connects the terminal a to the terminal c. However, when the power of the wireless carrier f3 is equal to or more than the specified value or when AGC control information is input, the AGC
The control unit 13 connects the first switch 2-1 to the terminal a and the terminal
Since the connection between the b-side is changed, the terminal of the first switch 2-1
The signal leaked from a to the terminal c is the BPF3-2 and the second switch 2-2
Is passed to the amplifier 4 and amplified. That is, the isolation of the first switch 2-1 is set to L (for example, general-purpose
Assuming that the GaAs switch MMIC is L = 20 dB or more), the first switch 2-1 controls the AGC of the attenuation amount L under the control of the AGC controller 13.
Since an operation equivalent to a circuit (variable attenuator) is performed, when a high-power signal is input, saturation of the input received signal can be avoided.

[0027] Even in a communication system that communicates with a base station, it is also predicted that the mobile station will actually pass around the base station (in the worst case, directly below the antenna) and the received power will exceed a specified value. However, the AGC control of the present method can improve the saturation of the received signal by at least 20 dB or more. In the above-described embodiment, the receiving apparatus including two BPFs having different pass bands (pass frequency bands) has been described. However, the number of BPFs having different passbands is not limited to two, and may be three or more. Accordingly, the number of switching terminals of the switching device and the number of connection of control signals also increase.

[0028]

As described above, according to the AGC control method of the present invention, an AGC circuit can be easily realized by using the blocks of the conventional receiver. Therefore, the dynamic range of the receiving apparatus can be very easily improved without significantly increasing the number of parts, the cost of the apparatus, and the mounting area, and the mobile stations can communicate with each other in a short distance, or around the base station (directly below the antenna). , The required reception characteristics can be secured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a receiving apparatus according to an embodiment of the present invention.

FIG. 2 is a processing flowchart of an embodiment of an AGC control unit of the present invention.

FIG. 3 is a block diagram showing a configuration of a conventional mobile station receiver.

FIG. 4 is a schematic diagram for explaining an SCPC communication method.

[Explanation of symbols]

1: Input terminal, 2-1 and 2-2: Switch, 3-1 and 3-2: BPF,
4: Amplifier, 5: Mixer, 6: IF filter, 7: Demodulation section, 8: Frame processing section, 9-1, 9-2: Oscillator, 1
0, 10 ': control unit, 11: power detector, 12: output terminal, 13: AGC control unit 41: base station, 42 to 46: mobile station, 500: operation area, 501 to 504: communication path.

Claims (9)

[Claims] 1. A receiving apparatus comprising: a plurality of bandpass filters having different passbands, wherein one of the plurality of bandpass filters is selected and used in accordance with a frequency band of an input received signal. A first switch for connecting an input received signal and any one of the plurality of band-pass filters, and connecting a band-pass filter corresponding to a frequency band of the input received signal to a subsequent stage of the receiving apparatus; And a second switch that connects a band-pass filter corresponding to a frequency band of the input received signal and the post-stage unit by using the second switch. Then, the input signal is attenuated by disconnecting the first switch between the input received signal and a band-pass filter corresponding to the frequency band of the input received signal. Receiving power control method. 2. The received power control method according to claim 1, wherein the received power of the input received signal is detected, and when the detected received power is equal to or more than a predetermined value, the connection of the first switch is established. A connection between the input received signal and a band-pass filter corresponding to a frequency band of the input received signal is disconnected. 3. A plurality of bandpass filters having different passbands, switching means for connecting a received signal to a corresponding bandpass filter from among the plurality of bandpass filters, and detecting a received signal power of the received signal. And a control unit for generating a control signal for controlling the switching unit. The control signal generated by the control unit, and the received signal power detected by the power information detection unit And when the received signal power is greater than or equal to a predetermined value, changing the connection of the received signal to a control signal for switching to another band-pass filter. 4. The reception power control method according to claim 3, further comprising: inputting second control information for controlling connection of said switching means, and when there is said second control information, receiving said reception signal. Characterized in that the connection is changed to a control signal for switching to another bandpass filter. 5. The reception power control method according to claim 3, wherein there are two bandpass filters having different passbands, and the two bandpass filters are switched alternately. The received power control method. 6. A plurality of band-pass filters having different pass bands, switching means for connecting a received signal to a corresponding band-pass filter among the plurality of band-pass filters, and detecting a received signal power of the received signal. And a control unit for generating a control signal for controlling the switching unit. The control signal generated by the control unit, and the received signal power detected by the power information detection unit And if the input received signal power is greater than or equal to a predetermined value,
An AGC control unit that changes the connection of the reception signal to a control signal for switching to another band-pass filter and controls the switching unit, wherein the control is performed when the input reception signal power is less than a predetermined value. The control signal generated by the means is given to the switching means as it is, and when the input received signal power is equal to or more than a predetermined value, the control signal is changed to a control signal for switching the connection of the received signal to another bandpass filter. Receiving means for receiving the received signal by giving the signal to the switching means. 7. The receiving apparatus according to claim 6, further comprising: input means for changing a connection of the bandpass filter, wherein when a switching instruction is given to the AGC control unit by the input means, A receiving apparatus for receiving the reception signal by changing the connection to a control signal for switching to another band-pass filter and applying the control signal to the switching means. 8. A plurality of bandpass filters having different passbands, switching means for connecting a received signal from the plurality of bandpass filters to a corresponding bandpass filter according to a reception band to be used, and said bandpass filter An amplifier that amplifies the reception signal band-limited by the filter, an oscillator that generates a local signal, a unit that demodulates the amplified reception signal using the local signal, a unit that detects power of the reception signal, In a receiving apparatus having first control means for generating a first control signal for controlling connection of a switching means, first control information of an output of the first control means, power information of an output of the power detection means, And a second control means for outputting control information for controlling connection of the switching means. 9. A step of inputting a first control signal output from the first control means using the receiving device according to claim 8,
The output of the power detection means is compared with a specified value to determine the magnitude (first
), Determining whether there is a second control signal input from another (second condition), and at least one of the first condition or the second condition is satisfied. In this case, the step of updating the content so as to switch the connection information of the switching means represented by the input first control signal to another connection, and the step of outputting the updated control information to the switching means A received power control method characterized by controlling.