JP3123965B2 - Transmission / reception signal level setting system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates also relates to a transmission and reception signal level setting system relates especially reception signal level setting system between common amplifier unit and connected modem to a coaxial cable of the radio base station apparatus.

[0002]

2. Description of the Related Art A conventional example of this kind will be described with reference to the drawings.

FIG. 9 is a block diagram showing a first conventional example.

In FIG. 9, a radio base station apparatus 101 according to the first conventional example includes a common amplifying apparatus 102 for amplifying a high frequency signal at a constant amplification factor and a variable attenuator for mechanically varying the level of the high frequency signal. 106 and level meter 11
6 and a signal path 106 comprising coaxial cables 1061, 1062, and 1063 for connection between the apparatuses. When the radio base station apparatus 101 communicates with mobile terminals, the level diagram of the radio channel zone design is determined by the uplink / downlink antenna gain, transmission power, reception sensitivity, and transmission path propagation loss.

[0005] For example, since the common amplifier 102 has a fixed gain, the transmission output power on the transmitting side is equal to the level input to the common amplifier 102 = the output power from the modem 103 and the transmission power of the transmission path 107. It was determined artificially by the insertion loss. Therefore, after confirming the insertion loss of the coaxial cable, one of the variable attenuators 106 in the
After initial setting to an approximate value for coarse adjustment in dB steps, the operator checks the output power at the output terminal of the common amplifying device 102 and looks at the output level meter 116 of the variable attenuator 106 to determine the fineness in 0.2 dB steps. It was reset to a certain value for adjustment.

On the other hand, since the upstream level diagram, that is, the reception input power on the receiving side is determined by the input power at the input terminal of the upstream common amplifier 102 and the insertion loss of the signal path 107, the operator needs to use the modulation / demodulation device 103. The variable attenuator 10 in the modem 3 is checked with the input power level meter 116.
6 had been adjusted.

As described above, in order to adjust the up / down level, the variable attenuator 10 is necessarily included in the modem 103.
6 and a level meter 116 had to be provided.

[0008] As described above, Japanese Patent Application Laid-Open No. 6-29 discloses a second conventional example in which transmission control is performed by performing gain control in consideration of the influence of the cable only at the down level when there are two devices.
No. 1685 (invention title: transmission output control system).

FIG. 10 is a block diagram showing a second conventional example.

[0010] In the second conventional example shown in FIG. 10, in an outdoor unit 220, a transmission frame from an indoor unit 210 is converted into a digital signal by a modem 226 and input to a microcomputer 221. The microcomputer can know the output level of the indoor device 210 by interpreting the signal input via the modem 226. The signal transmitted from the indoor device 210 is transmitted to the antenna 227 via the amplifier 222, the variable attenuator 223, and the level detection circuit 224. The signal level output from the indoor device 220 is detected by a level detection circuit 224, converted into a digital signal by an A / D converter 225, and input to the microcomputer 221. The microcomputer 221 determines whether or not the output level of the outdoor device 220 is equal to the preset output gain of the output level of the indoor device 210 based on the signal detected by the level detection circuit 224. Is generated, the variable attenuator 223 is controlled so that the gain value becomes the set gain value. As a result, when viewed from the indoor device 210, the outdoor device 220 can perform gain control in a system including the cable 217, and the difference in control is eliminated due to the difference in the cable 217.

[0011]

According to the conventional system for setting the transmission / reception signal level and the setting method therefor, in the case of the first conventional example, first, after confirming the insertion loss of the coaxial cable, the transmitting side modulates and demodulates. After the initial setting to a predetermined value with the variable attenuator in the device, the operator again set the variable attenuator in the modem while checking the output power at the output terminal of the common amplifying device. However, when the common amplifying device and the modem are physically separated, one worker checks the level with a measuring instrument, and the other person adjusts the variable attenuator of the modem. There was a problem that it was bad.

Also, since the transmission power cannot exceed the level prescribed by the Radio Law, a very fine system is required for the variable attenuator in order to absorb the variation in the value of the insertion loss of a coaxial cable or the like, and a 1 dB step is required. For coarse adjustment of 0.2
It is necessary to provide for fine adjustment of the dB step, and there is a problem in that the size and cost of the modulation / demodulation device are prevented.
On the other hand, the receiving side has decided to keep the gain of the common amplifying device and the input level of the input end of the coaxial cable insertion loss modulation / demodulation device constant in order to maintain the receiving gain. In addition, there is a problem that the workability is poor because the variable attenuator in the modem is adjusted while checking the level using the measuring equipment in the modem.

Further, when the level may be set without much concern for the reception level, the operator sets the variable attenuator in the modem with reference to the correspondence table. In such a case, when the coaxial cable has a failure such as a disconnection, the level of the common amplifying device and the modulation and demodulation device may be investigated while being separated, so that there is a problem that the number of steps is extremely large.

Next, in the case of the second conventional example, since a microcomputer is used and a program for level setting is also required, there is a problem that the cost is increased as a whole.

[0015]

[0016]

[0017]

SUMMARY OF THE INVENTION A transmission / reception level setting system according to the present invention includes a common amplifying device for amplifying a high-frequency signal at a constant amplification factor, and a modulation / demodulation system comprising a gain control means for varying the level of the high-frequency signal. Device, and a signal path composed of a plurality of coaxial cables for transmitting the high-frequency signal connected between the common amplifying device and the modulation and demodulation device, wherein the common amplifying device is configured to transmit and receive. A transmission / reception amplifying unit for amplifying the high-frequency signal at a constant amplification degree; and a DC voltage generating / superimposing unit for superimposing a DC voltage on the high-frequency signal on each of the plurality of coaxial cables. And separating the high-frequency signal and the received DC voltage from each of the plurality of coaxial cables based on the voltage value of the received DC voltage. An electronic variable attenuator that automatically sets the level of the high-frequency signal between the common amplifying device and the modem corresponding to each length, and modulates and demodulates the automatically set high-frequency signal to an external A transmission / reception modulation / demodulation unit for transmitting and receiving signals to / from a transmission path, wherein the signal path includes a transmission coaxial cable for transmitting the high-frequency signal, a 0-system reception coaxial cable for receiving the high-frequency signal, and a 1-system reception. A DC voltage generating / superimposing unit for generating a DC voltage having a predetermined constant voltage; and a DC voltage generating / superimposing unit for generating a DC voltage for a high frequency signal of the transmission / reception amplifying unit. And a superimposing section for superimposing the constant-voltage DC voltage from the section on the plurality of coaxial cables, wherein the superimposing section includes respective core wires of the transmitting, 0-system receiving and 1-system receiving coaxial cables. , First for the high-frequency signal blocking to connect independently between said DC voltage generating unit
And a DC blocking first capacitor independently connected between the coil and the transmission / reception amplifying unit. The electronic variable attenuator includes a DC voltage received from each of the plurality of coaxial cables and a transmission / reception attenuator. A separation unit that separates a received high-frequency signal, a control / abnormality detection unit that determines whether the received DC voltage is within a preset reference voltage range, and a result of the determination by the control / abnormality detection unit, respectively. A high-frequency attenuating unit for attenuating high-frequency signals corresponding to each of the plurality of coaxial cables from the separating unit based on the received DC voltage, and connecting the attenuated high-frequency signals to the transmitting / receiving modem unit; A second capacitor having one end independently connected to each core of each of the plurality of coaxial cables and the other end independently connected to the high-frequency attenuator;
A second coil having one end independently connected to the other end of each of the second capacitors, and the other end independently connected to the control / abnormality detection unit, wherein one end of the high-frequency attenuation unit is A third capacitor connected to the other end of each of the plurality of coaxial cables from the separation unit, a pin diode connected to the other end of the third capacitor as an anode, and one end connected to the cathode of the pin diode. A fourth resistor having one end connected to the ground, one end connected to a common connection point between the cathode of the pin diode and the other end of the first resistor, and a fourth end connected to the transmission / reception modem. A capacitor, a third coil having one end independently connected to the control / abnormality detection unit, and one end connected to one end of the third coil, and the other end connected to the other end of the third capacitor and the pin diode. Anode and And a second resistor connected to the common connection point.

[0018]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a portable radio base station apparatus according to one embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of a superposition unit of a common amplifying apparatus according to this embodiment, and FIG. FIG. 4 is a circuit diagram illustrating an example of a separation unit of the modem in the embodiment, FIG. 4 is a block diagram illustrating an example of a control / abnormality detection unit of the modem in the embodiment, and FIG. 5 is high-frequency attenuation of the modem in the embodiment. It is a circuit diagram showing an example of a section.

In FIG. 1, a portable radio base station apparatus 1 according to the present embodiment includes a common amplifying apparatus 2 for amplifying a high-frequency signal at a fixed amplification factor, a modem apparatus 3 for performing a high-frequency signal modulation / demodulation process, and a common amplification apparatus. Three coaxial cables 61 for transmitting a high-frequency signal and a DC voltage between the device 2 and the modem 3
And a signal path 6 comprising 62 and 63.

The common amplifying device 2 includes a transmission / reception amplifying section 7 for amplifying a high frequency signal of transmission / 0 system reception / 1 system reception at a constant amplification factor, and a DC voltage generating section 8 for generating a DC voltage.
And a DC voltage generating / superimposing circuit 4 having a superimposing section 9 for superimposing a DC voltage and a high-frequency signal.

On the other hand, the modulator / demodulator 3 transmits / receives the 0 system /
A transmission / reception modulation / demodulation unit 10 that modulates / demodulates / receives an electric field a high-frequency signal received by the first system, a separation unit 1 that separates a DC voltage and a high-frequency signal, and a high-frequency attenuator 12 that attenuates the high-frequency signal according to a control voltage. And control / abnormality detector 1 for outputting a control voltage corresponding to a DC voltage and detecting a voltage abnormality
3 and an electronic variable attenuator 5 having the same.

In FIG. 2, superimposing section 9 in DC voltage generating / superimposing section 4 according to the present embodiment includes capacitors C for blocking DC for transmission / reception for 0 system / reception for 1 system.
_11, C _12, C ₁₃ and coil L ₁₁ of the high-frequency signal blocking,
An example for transmission composed of L ₁₂ and L ₁₃ will be described.
A terminal for applying a DC voltage (V1) from the DC voltage generator 8, a capacitor C ₁₁ for conducting a high frequency only transmission / reception amplification section 7 conducts a DC voltage connected to the transmission coaxial cable 61 high-frequency signals composed of L ₁₁ Metropolitan for blocking.

[0024] Similarly 0-system reception system is a capacitor C ₁₂ and the coil L ₁₂ Prefecture, 1 system receiving system is composed of a capacitor C ₁₃ and the coil L ₁₃ Prefecture.

In FIG. 5, the high-frequency attenuator 12 in the electronic variable attenuator 5 according to the present embodiment includes capacitors C for blocking DC for transmission / reception for system 0 / reception for system 1 respectively.
₁₄ , C ₁₅ , C ₁₆ , C ₁₇ , C ₁₈ , C ₁₉ , high frequency signal blocking coils L ₁₄ , L ₁₅ , L ₁₆ and pin diodes X ₁₁ , X ₁₂ , X ₁₃ for determining the attenuation of the high frequency signal And resistors R ₁₁ , which determine the biases of the pin diodes X ₁₁ , X ₁₂ , X ₁₃ .
An example for transmission is described, which is composed of R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , and R _16. A control for superimposing a high-frequency signal with a control voltage (V 3) connected to a coaxial cable 61 and transmitting the power to make it conductive is described. and the terminal, superimposed DC voltage conducts and the coil L ₁₄ to cut off the high-frequency signal, a capacitor C ₁₄ to block the DC voltage is made conductive only high frequency signals, the pin diode X ₁₁ to determine the high frequency attenuation, the Pin diode X
_The resistors R ₁₁ and R ₁₄ that determine the 11K bias condition,
And a capacitor C ₁₇ Metropolitan for conducting only the high-frequency signal to the receiving modem unit 10. Similarly, the 0-system receiving system includes capacitors C ₁₅ and C ₁₈ , a coil L ₁₅ , a pin diode X ₁₂ , resistors R ₁₂ and R _15, and a 1-system receiving system capacitors C ₁₆ and C ₁₉ , a coil L ₁₆ and a pin. diode X ₁₃ and the resistor R
And a _13, R ₁₆ Prefecture.

In FIG. 3, the separating unit 11 in the electronic variable attenuating unit 5 according to the present embodiment has
Each of them is a DC blocking capacitor C ₂₁ for system 1 reception,
Coil L ₂₁ of C _22, C ₂₃ and the high-frequency signal blocking, L _22, L
Is composed of _23, will be described an example for transmission, the capacitor C ₂₁ for conducting a superimposed signal of a DC voltage (V2) and the high frequency signal receiving from the transmission coaxial cable 61 to a high frequency only modem 3, a DC voltage and a coil L ₂₁ Metropolitan blocking the high frequency signal to conduct. Similarly 0-system reception system is a capacitor C ₂₂ and the coil L ₂₂ Prefecture, 1
System receiving system is composed of a capacitor C ₂₃ and the coil L ₂₂ Prefecture.

In FIG. 4, the control / abnormality detection unit 13 in the electronic variable attenuator 5 according to the present embodiment outputs a DC voltage (V2) which is an input voltage from the separation unit 11 for transmission / system 0 reception / system 1 reception. ) Are compared by the comparison circuits 14A, 14B and 14C, and if any one of them exceeds the threshold level, an alarm signal is reported. Further, the DC voltage (V2) is also output to the high frequency attenuator 12 as a control voltage (V3).

FIG. 6 is a diagram showing loss values of a high-frequency signal in three cases in the modulation / demodulation device according to the present embodiment, and FIG. 7 is an example of characteristics of a high-frequency attenuator of the modulation / demodulation device according to the present embodiment. FIG. 8 and FIG. 8 are flowcharts showing the procedure for setting the level of the modem in the present embodiment.

Next, the present embodiment uses the TDMA-FDD system as an access system, and π / 4 DQPS as a modulation system.
A case where the present invention is applied to a wireless base station apparatus employing the K system will be described with reference to FIGS.

In the radio base station apparatus 1 according to this embodiment, the modulation / demodulation device 3 and the common amplification device 2 are composed of coaxial cables 61 and 6.
2, 63, and communicates with and controls a mobile terminal (not shown). As described above, when the coverage of the service area radius Am is covered as the line design of the radio channel zone of the digital mobile communication system, uplink / downlink antenna gain, transmission power, reception sensitivity, and transmission path propagation loss. Thus, the wireless specifications of the wireless base station device 1 and the mobile terminal are determined.

For example, when the service area is covered with a radius A = 3 km, the radio base station apparatus 1 and the mobile terminal have 1 W / 0.6 W with respect to the transmission power and the reception sensitivity which are part of the radio specification. The sensitivity becomes 0 dBμV / 3 dBμV, and a predetermined UP / UP is established between the radio base station apparatus 1 and the mobile terminal.
A system level diagram has been constructed so that a received electric field level within a certain range is input to the DOWN LINK, that is, the radio base station apparatus 1 and the mobile terminal, so that voice and non-voice communication can be performed.

At this time, as the level diagram of the radio base station apparatus 1, the transmitting side is the output power (A) of the common amplifying apparatus 2 = 1.
W (30 dBm), AMP gain (X) = 40 dB, output level (Y) of modem 3 = 0 to -10 Bm, and coaxial cable (Z) = XdB. The transmission level diagram value is A = X + Y + Z. On the other hand, on the receiving side, in order to keep the reception input level (RSSI value) of the transmission / reception demodulation unit 10 constant, the input level MAX value (B) of the common amplification device 2 is -43 dBm, and the gain (X ')
= 10 dB, the maximum value (W) of the input level of the modem 3 = −33 dBm to −43 dBm, and the coaxial cable loss (Z) = X dB. The reception level diagram value (reception gain) is X ′ + Z = B−W = constant (fixed value).

Next, the operation of the level setting procedure according to the present embodiment will be described with reference to FIGS.

The transmission / reception between the common amplifier 2 and the modem 3
First, the common amplifier 2 and the modem 3 are connected by coaxial cables 61, 62, 63 for setting the reception level diagram. At this time, it is assumed that the GND potentials of the common amplifying device 2, the modulation / demodulation device 3, and the coaxial cables 61, 62, 63 are all conducted.

First, the DC voltage operation is confirmed.

First, a predetermined DC voltage (V1) is output from the DC voltage generator 8 in the common amplifier 2, and the DC voltage (V1) is output.
1) the coil L _11, L _12, L ₁₃ through the by transmission / 0-system receiving / 1 system receiving device between the coaxial cable 61, 62, 63 separator 11 that is mounted to the modem 3 via the via the coil _{L 21, L 22, L 23} , a DC voltage to each of the control terminal (V2, V2 ', V2 " ) is applied.

The DC voltage (V2 to V2 ″) is applied to the superposition section 9
Output DC voltage (V1) and coaxial cables 61, 62,
It occurs as a difference from the potential difference of the resistance loss proportional to the length of 63.

Here, the DC voltage (V2 to V2 ″) separated by the separation unit 11 is compared with the comparison circuit 1 of the control / abnormality detection unit 13.
Within the threshold level at 4A-14C (Vmin ~
Vmax), and if at least one of the three DC voltages is outside the threshold, it is determined to be abnormal and an alarm is reported.

On the other hand, under normal conditions, the DC voltage (V2 to V
2 ″) is applied as it is to the high frequency attenuator 12 as the control voltage (V3 to V3 ″).

Next, the control voltage (V3 to V3 ″) drives the high frequency attenuator 12 having the high frequency attenuating characteristic corresponding to the predetermined voltage value as shown in FIG. A driving example regarding the transmission system is shown below.

[0041] In the high-frequency attenuation unit 12, receiving the control voltage (V3) the resistance R ₁₁ via the coil L _14, a pin diode X ₁₁ resistor R ₁₄ by applying a bias voltage to determine the high frequency attenuation characteristics. Here, the resistors R ₁₁ and R ₁₄ are bias resistors of the pin diode X ₁₁ , and the pin diodes X 11
Reference numeral ₁₁ denotes, for example, HVM 14 manufactured by HITACHI. Similarly, the control voltage (V3 ″), the coil L ₁₆ , the resistor R ₁₃ , the pin diode and the control voltage (V 3 ″) are applied to the 0-system receiving system with the control voltage (V 3 ′), the coil L ₁₆ and the resistor R ₁₄ . A predetermined high-frequency attenuation is determined by X ₁₃ and the resistor R ₁₆ .

In the above DC voltage operation, sector 1
In this case, the level initial setting and the conduction confirmation are completed. Here, the level setting is completed, but when confirming with the level of the actual high-frequency signal, the following is performed.

In the case of the transmission system, a measuring device such as a power meter is connected to the output terminal of the common amplifying device 2, and a high-frequency signal is output from the transmission / reception modulation / demodulation unit 10. This high-frequency signal is supplied to the capacitor C ₁₇ -pin diode X of the high-frequency attenuator 12.
₁₁ - is attenuated by a predetermined attenuation amount in the capacitor C _14, is input via the capacitor C ₂₁ of the separator 11 to the transmission coaxial cable 61- superimposing section 9.

The input high frequency signal is supplied to the output terminal is fixed amplified by via a capacitor C ₁₁ transmit / receive amplifier section 7 of the overlapping portion 9.

On the other hand, in the case of the 0-system receiving system, the common amplifying device 2
Connect a signal generation prayer measuring device to the input terminal of, and output a high frequency signal. The RF signal coaxial cable system 0 received via the capacitor C ₁₂ of the overlapping portion 9 61- separation unit 1
1 is input.

The input high-frequency signal passes through the capacitor C ₂₂ of the separation unit 11 and the capacitor C of the high-frequency attenuation unit 12.
_The signal is attenuated by a predetermined amount by a ₁₅ -pin diode X ₁₂ and a capacitor C ₁₈ and supplied to the transmission / reception modulation / demodulation unit 12 to detect an electric field (RSSI value). Similarly, in the case of the 1-system receiving system, the high-frequency signal passes through the capacitor C ₁₃ of the superimposing unit 9, the coaxial cable 63 for the 1-system receiving, the capacitor C ₂₃ of the separating unit 11, the capacitor C ₁₆ of the high-frequency attenuating unit 12, and the pin. The signal is attenuated by a predetermined amount by a diode X ₁₃ -capacitor C ₁₉ and supplied to the transmission / reception modulation / demodulation unit 12 to detect an electric field (RS
(SI value). However, the DC voltage operation check = the high-frequency signal operation level check should have been established in the initial setting, so the high-frequency signal operation check is not particularly necessary.

For example, as shown in FIG. 6, the radio base station apparatus 1 has a three-sector configuration, a transmission output of 1 W, and a reception gain = 0.
coaxial cable 61 for dB, transmission, system 0 and system 1 reception,
62, 63 cable length is 1/2 in sector 1/2/3
/ 10 m and DC voltage V1 of DC superimposing circuit 4 = 15 V,
The case where the load current of the electronic variable attenuator 5 is 1A and the resistance of the coaxial cable is 1Ω / m will be described with reference to FIG.

In the case of sector 1 (coaxial cable length = 1 m)
First, when the coaxial cable 61 is connected first (S1), a predetermined DC voltage V1 = 15V is output from the DC voltage generator 8 in the common amplifying device 2 (S2, S3), and the superposition unit 9 and the coaxial cable between the device are output. When passing through 61, a potential difference of 1 V is generated from the product of the load current 1A and the resistance value of the coaxial cable 61 of 1Ω, and the DC voltage V2 (15V-1V) is supplied to the separation unit 11 (S4). This DC voltage is supplied to the control / abnormality detection unit 13
Is determined to be within 4 V to 15 V and recognized as normal (S5).

Further, the DC voltage V2 is controlled by the control voltage V3 (14
V) is applied to the high frequency attenuator 12 (S6). Here, since the electronic variable attenuator 5 has a voltage of 14 V,
The ATT value of 9.5 dB is set based on the circuit constant of (1) and the characteristics of FIG. 7 (S7).

As a result, for example, on the transmission side, the output power of the modulation / demodulation device 3 is determined by the ATT value of the electronic variable attenuator 5 being the maximum output voltage (ATT value = −0 dB (1 mW)) − 9.5 dB.
9.5 dBm is output. Since this power passes through the coaxial cable 61 having a loss of 1.5 dB, -10 dB is supplied to the common amplifying device 2. Therefore, since the gain of the common amplifying device 2 is 40 dB, the output voltage of the common amplifying device 2 is 1 W (30 dBm = −10 dBm + 40 dB).

On the other hand, on the receiving side, the maximum input value to the common amplifier 2 is -43 dBm, and the gain of the common amplifier 2 is 10 d.
B, 0.5 dB coaxial cable 62, electronic variable attenuator 5
Is 9.5 dB, and the input power of the modem 3 is −43 dBm (−43 dBm + 10 dB−0.5 dB).
B−9.5 dB), and the receiving gain is set to 0 dB.

As described above, at the same time as setting the level, it can be confirmed at the same time that the control voltage generated when the disconnection 62 occurs in the coaxial cable is not applied.
An abnormality of the coaxial cable can also be determined.

In the case of sector 2 (coaxial cable length = 2 m)
Of the electronic variable attenuator 5 has a control voltage of 1
When 3 V (15 V-2 V) is applied, the ATT value of 9 dB is set from the circuit constant of the high frequency attenuator 15 because the high frequency loss of the coaxial cable 61 of the electronic variable attenuator 5 is 1 dB. As a result, the output power of the modulation / demodulation device 3 is set such that the ATT value of the electronic variable attenuator 5 has a maximum output power of −9 dB.
9 dBm is output, -10 dBm is supplied to the common amplifying device 2 through a 1 dB loss coaxial cable, and the output power of the common amplifying device 2 is 1 W (30 dBm = -10 dBm + 4).
0 dB). The same applies to the receiving system.

In the case of sector 3 (coaxial cable length = 10
m), the control voltage of 5V (15V-10V) is applied, and the same setting is possible.

[0055]

As described above, the present invention provides a common amplifying device for amplifying a high-frequency signal with a constant amplification factor, a modem device having gain control means for varying the level of a high-frequency signal, and a common amplifying device. A signal path comprising a plurality of coaxial cables for transmitting a high-frequency signal connected to a modem, wherein the common amplifying device superimposes a DC voltage on the high-frequency signal on each of the plurality of coaxial cables. A DC superimposing means is provided, and the modem includes electronic variable attenuating means for performing gain control corresponding to the attenuation of the DC voltage by a coaxial cable, and the electronic variable attenuating means is provided between the common amplifying device and the modem corresponding to the coaxial cable length. By having a passive element circuit means including a pin diode for automatically setting the level of a high-frequency signal, a common amplifier and a modem can be connected. Can be performed all level diagram set only automatically by connecting a coaxial cable, there is an effect that it is possible to improve the conventional worker maintainability.

Further, since the conduction of the coaxial cable can be confirmed in advance at the time of the initial connection by the DC voltage without using the RF signal, the test time for the initial setting between the common amplifying device and the modem can be reduced, and the equipment of the modem can be reduced. There is an effect that can be simplified as compared with the related art.

Further, since the high frequency signal level is automatically set by the passive element circuit means without using an active element such as a microcomputer for the electronic variable attenuating means, programs for the microcomputer can be created. It is unnecessary and has an effect that it can be constructed economically.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a wireless base station device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram illustrating an example of a superposition unit of the common amplifying device according to the present embodiment.

FIG. 3 is a circuit diagram illustrating an example of a separation unit of the modem in the present embodiment.

FIG. 4 is a block diagram illustrating an example of a control / abnormality detection unit of the modem according to the present embodiment.

FIG. 5 is a circuit diagram illustrating an example of a high-frequency attenuator of the modem in the present embodiment.

FIG. 6 is a diagram illustrating loss values of a high-frequency signal in three cases in the modulation / demodulation device according to the present embodiment.

FIG. 7 is a diagram illustrating an example of characteristics of a high-frequency attenuator of the modem in the present embodiment.

FIG. 8 is a flowchart showing a procedure for setting a level of the modem in the present embodiment.

FIG. 9 is a block diagram showing a first conventional example.

FIG. 10 is a block diagram showing a second conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 wireless base station device 2 common amplifying device 3 modulation and demodulation device 4 DC voltage generation / superposition unit 5 electronic variable attenuation unit 6 signal path 7 transmission / reception amplification unit 8 DC voltage generation unit 9 superposition unit 10 transmission / reception modulation / demodulation unit 11 separation unit 12 High-frequency attenuator 13 Control / abnormality detector 61 Coaxial cable for transmission 62 Coaxial cable for system 0 reception 63 Coaxial cable for system 1 reception

Claims (2)

(57) [Claims] 1. A common amplifying device for amplifying a high-frequency signal with a fixed amplification degree, a modem device having gain control means for varying a level of the high-frequency signal, and a modem connected between the common amplifying device and the modem device. And a signal path comprising a plurality of coaxial cables for transmitting the high-frequency signal, wherein the common amplifying device amplifies the high-frequency signal for transmission and reception with a certain amplification factor. And a DC voltage generating / superimposing unit for superimposing a DC voltage on the high-frequency signal on each of the plurality of coaxial cables, and the modem device receives the high-frequency signal and the DC voltage received from each of the plurality of coaxial cables. And the common amplifying device and the modulation / demodulation device corresponding to the respective lengths of the plurality of coaxial cables based on the voltage value of the receiving DC voltage. An electronic variable attenuator for automatically setting the level of the high-frequency signal between devices, and a transmission / reception modulator / demodulator for modulating and demodulating the automatically set high-frequency signal and transmitting and receiving the signal to an external transmission path. And the signal path includes a transmission coaxial cable for transmitting the high-frequency signal and a transmission coaxial cable for receiving the high-frequency signal.
A coaxial cable for system reception and a coaxial cable for system 1 reception, wherein the DC voltage generation / superposition unit includes a DC voltage generation unit that generates a DC voltage of a predetermined constant voltage, and a transmission / reception amplification unit. A superimposing section for superimposing the constant-voltage DC voltage from the DC voltage generating section on the plurality of coaxial cables with respect to the high-frequency signal, wherein the superimposing section includes the transmission, the 0-system reception, and the 1-system reception. A first coil for cutting off the high-frequency signal, which is independently connected between each core of the coaxial cable for use, and the first coil for cutting off the high-frequency signal, and a DC blocking, which is connected independently between the transmitting / receiving amplifying section. A first capacitor, wherein the electronic variable attenuator has a separator for separating the DC voltage received from each of the plurality of coaxial cables and a high-frequency signal for transmission / reception, and the received DC voltage is previously set. A control / abnormality detection unit that determines whether the plurality of coaxial cables are within the range of the reference voltage, and the plurality of coaxial cables from the separation unit based on the received DC voltage of each of the determination results of the control / abnormality detection unit. A high-frequency attenuator for attenuating a corresponding high-frequency signal and connecting the attenuated high-frequency signal to the transmission / reception modulation / demodulation unit, wherein the separation unit has one end independently connected to each core of each of the plurality of coaxial cables. A second capacitor whose other ends are independently connected to the high-frequency attenuator; one end is independently connected to the other ends of the second capacitors, and the other ends are independently connected to the control / abnormality detector; A transmission / reception signal level setting system, comprising: 2. A high-frequency attenuating section, a third capacitor having one end connected to the other end of each of the plurality of coaxial cables from the separating section, and a pin diode anode-connected to the other end of the third capacitor. And one end connected to the cathode of this pin diode and the other end connected to ground.
And a fourth capacitor having one end connected to a common connection point between the cathode of the pin diode and the other end of the first resistor and the other end connected to the transmission / reception modem, and one end connected to the control / abnormality. A third coil independently connected to the detection unit, one end connected to one end of the third coil, and the other end connected to a common connection point between the other end of the third capacitor and the anode of the pin diode; reception level setting system according to claim 1, characterized in that it comprises a second resistor.