JP4339366B2 - Wireless communication system - Google Patents

Description

  The present invention relates to a radio communication system, and more particularly to a large-capacity millimeter wave radio communication system.

  In recent years, wireless communication systems using millimeter waves have been developed in order to cope with an increase in capacity of wireless communication. Recently, a wireless communication system that realizes a communication speed of 10 Gbps using a millimeter wave of 120 GHz band has also been developed (see, for example, Non-Patent Document 1).

  In such a millimeter wave radio, an optical signal (optical millimeter wave signal) whose intensity is modulated at a frequency in the millimeter wave region is generated as an optical signal, and an electromagnetic wave is generated by photoelectrically converting the optical millimeter wave signal. The technique to make is examined. A configuration of a wireless communication system using such an optical technology is shown in FIG. In this system, an optical signal (optical subcarrier signal) whose intensity is modulated at the frequency of the millimeter wave signal is generated by a method such as an optical heterodyne method. Thereafter, the optical subcarrier signal is intensity-modulated using an optical modulator. The optical subcarrier signal whose intensity is modulated by the data signal is photoelectrically converted by the photodiode, then amplified by the millimeter wave amplifier, and radiated from the antenna to the space.

  On the other hand, in such a millimeter-wave radio, the output of the device to be used is limited, so the output of the radio device is only about several tens of mW. Also, in the receiver, the minimum reception sensitivity of the millimeter wave detector used in the receiver is -50 dBm as a result of the fact that a low NF amplifier cannot be obtained or the noise power increases due to wideband data transmission. Only a degree is obtained. As described above, since the output of the transmitter is low and the reception sensitivity is low, in order to perform data transmission of about 1 km, it is necessary to use an antenna having a very high directivity with an antenna beam width of 1 degree or less. is there.

In addition, when using such an antenna with a narrow beam width, precise antenna alignment is required between the transmitter and the receiver. Therefore, the automatic direction that automatically detects the antenna orientation that provides the maximum reception sensitivity. The introduction of an adjustment mechanism is expected. For example, in the wireless communication system 800 shown in FIG. 7, the maximum received power is referred to with reference to the DC component of the output of the detector or the voltage (monitor voltage) output according to the millimeter wave signal intensity input to the detector. The antenna azimuth that can be obtained is detected.
Hirata, A. et al, "120-GHz-Band Millimeter-Wave Photonic Wireless Link for 10-Gb / s Data Transmission", IEEE Transactions on Microwave Theory and Techniques, Volume 54, Issue 5, May 2006 pp.1937-1944 .

  However, in the conventional wireless communication system, when the DC voltage is monitored, when the extremely small power is input due to the minimum sensitivity of the voltmeter or the problem of noise, the power cannot be detected. There was a problem that it could not be measured as fluctuations in

  In view of the above-described problems, the present invention detects a received power in a large-capacity millimeter-wave wireless communication system even when the intensity of a millimeter-wave signal received by a receiver is small, so It is an issue to adjust.

The wireless communication system of the present invention according to claim 1 is a wireless communication system comprising a transmitter for transmitting a millimeter wave signal and a receiver for receiving a millimeter wave signal transmitted by the transmitter. Has a light source for generating an optical subcarrier signal that generates an optical subcarrier signal that is intensity-modulated at the frequency of the millimeter wave signal as a carrier wave, a data signal to be transmitted, and a gain adjustment terminal. A power detection frequency signal having a frequency lower than that of the data signal to be transmitted is input to the baseband amplifier that modulates the data signal with the power detection frequency signal, and the baseband amplifier amplifies and detects the power. An optical modulator that modulates the intensity of an optical subcarrier signal with a data signal modulated with a frequency signal for use, and an optical signal that is modulated with an optical modulator. For monitoring, a transmitting antenna that transmits an electrical signal photoelectrically converted by the photodiode as a millimeter-wave signal, and a signal that is branched from an optical signal whose intensity is modulated by an optical modulator into an electrical signal for output A bias adjustment circuit comprising: a photodiode; a DC voltage source that applies a bias voltage to the optical modulator; and a feedback circuit that receives the output of the monitoring photodiode and adjusts the output of the DC voltage source. use frequency signal is also used to adjust the degree of modulation of the optical modulator in the bias adjustment circuit, the receiver, measuring the intensity of the received millimeter-wave signal by extracting the frequency signal power detection It is characterized by.

In the present invention, the transmitter transmits a millimeter wave signal intensity-modulated with a power detection frequency signal having a frequency lower than that of the data signal to be transmitted, and the receiver detects power extracted from the received millimeter wave signal. by was Teisu so that measuring the intensity of the frequency signal is output from when the intensity of the millimeter-wave signal due to noise or the like is small even according to the intensity of the received millimeter wave signal of the prior art millimeter wave detector As compared with the case where the DC voltage is measured, a higher S / N is obtained, so that the reception sensitivity is improved.

  In the present invention, the transmitter transmits a millimeter wave signal modulated at a power detection frequency lower than the frequency of the data signal to be transmitted, and the receiver receives the data signal component and the power detection frequency signal. It becomes possible to separate the components.

  In the present invention, the transmitter receives the input of the frequency signal for power detection by the baseband amplifier, and intensity-modulates the optical subcarrier signal as a carrier wave with the data signal amplified by the baseband amplifier by the optical modulator. By doing so, it is possible to modulate the millimeter wave signal with the frequency signal for power detection lower than the frequency components of the optical subcarrier signal and the data signal by using the bias voltage automatic adjustment mechanism of the optical modulator.

  The wireless communication system of the present invention according to claim 2 is a wireless communication system comprising a transmitter for transmitting a millimeter wave signal and a receiver for receiving a millimeter wave signal transmitted by the transmitter, The machine generates a millimeter-wave signal as a carrier wave and modulates the intensity of the millimeter-wave signal with a data signal to be transmitted, and a gain adjustment of the millimeter-wave signal output from the millimeter-wave signal generation circuit. A millimeter-wave amplifier that modulates the intensity with a frequency signal for power detection that is lower in frequency than the data signal to be transmitted that is input to the terminal, and a transmission antenna that transmits the millimeter-wave signal output from the millimeter-wave amplifier. The machine is characterized by extracting a power detection frequency signal from the received millimeter wave signal and measuring its intensity.
  In the present invention, the transmitter generates a millimeter wave signal as a carrier wave by the millimeter wave signal generation circuit, modulates the intensity of the millimeter wave signal with the data signal to be transmitted, and further adjusts the gain of the millimeter wave amplifier. By using the terminal to intensity-modulate the millimeter wave signal with the input power detection frequency signal, the millimeter wave signal has a power detection frequency signal lower than the frequency component of the millimeter wave signal and data signal as a carrier wave. Can be modulated.

  The receiver in the wireless communication system of the present invention according to claim 3 is a reception antenna that receives a millimeter wave signal, a millimeter wave detector that demodulates the millimeter wave signal received by the reception antenna, and a millimeter wave detector that demodulates the millimeter wave signal. A coupler that bifurcates a millimeter wave signal, a filter circuit that extracts a power detection frequency signal from one of the millimeter wave signals branched by the coupler, and amplifies and outputs the power detection frequency signal extracted by the filter circuit A narrowband amplifier, means for measuring the intensity of a frequency signal for power detection output from the narrowband amplifier, and means for extracting a data signal from the other millimeter-wave signal branched by the coupler, To do.

Receiver in a wireless communication system of the present invention according to claim 4 includes a receiving antenna for receiving a millimeter wave signal, and the millimeter wave detector for demodulating the millimeter wave signal received by the receiving antenna, the millimeter wave detector is demodulated extracting the frequency signal data signal及 beauty power detection from the millimeter wave signal, and a bias T having an output terminal for outputting the respective means for measuring the intensity of the extracted power detection frequency signal by the bias T, It is characterized by providing.

  In the present invention, the receiver includes a bias T having an output terminal for extracting the data signal component and the signal component of the power detection frequency from the millimeter wave signal demodulated by the millimeter wave detector and outputting each of them. As a result, the number of parts can be reduced and the receiver can be made compact.

Receiver in a wireless communication system of the present invention according to claim 5 includes a receiving antenna for receiving a millimeter wave signal, and the millimeter wave detector for demodulating the millimeter wave signal received by the receiving antenna, the millimeter wave detector is demodulated a coupler for bifurcation millimeter wave signal is input one of the millimeter wave signal branched by the coupler, and the narrow-band amplifier that amplifies the frequency band of the signal of the power detection frequency signal, the narrow-band amplifier output Is input by the filter circuit that passes the frequency signal for power detection, the detector that detects the signal component that the filter circuit has passed, the voltmeter that measures the voltage value of the signal component output by the detector, and the coupler Means for extracting a data signal from the other branched millimeter wave signal .

  In the present invention, in the receiver, after the millimeter wave signal demodulated by the millimeter wave detector is branched by the coupler, the signal component of the power detection frequency band that has passed through the filter circuit is detected by the detector. Thus, by adopting a configuration in which the voltage value of the signal component output from the detector by the voltmeter is measured, a receiver can be configured at a lower cost than a configuration using an expensive analyzer.

Receiver in a wireless communication system of the present invention according to claim 6 includes a receiving antenna for receiving a millimeter wave signal, demodulates the millimeter wave signal received by the receiving antenna, and outputs the data signal from the millimeter wave signal demodulated an output terminal, an output terminal for outputting a monitor voltage corresponding to the intensity of the received millimeter-wave signal, Bei example a millimeter wave detector which outputs a frequency signal power detection from the terminal for outputting a monitor voltage as a monitor voltage And means for measuring the intensity of the frequency signal for power detection output from the terminal for outputting the monitor voltage of the millimeter wave detector .

  In the present invention, in the receiver, the millimeter wave detector that demodulates the received millimeter wave signal has an output terminal that outputs a data signal from the demodulated millimeter wave signal and the intensity of the received millimeter wave signal. It has an output terminal that outputs a monitor voltage, and the signal component of the frequency for power detection is extracted from the terminal that outputs the monitor voltage, thereby reducing the number of parts compared to the configuration using the coupler. The receiver can be made compact.

In the radio communication system of the present invention according to claim 7 , the transmitter and the receiver transmit and receive millimeter wave signals using a highly directional antenna having a beam width of 1 degree or less .

  According to the wireless communication system of the present invention, the antenna orientation can be adjusted in a short time when the antenna is installed. Further, even when an antenna axis deviation occurs between the transmitter and the receiver during data transmission, the orientation of the antenna can be adjusted without stopping the data transmission.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
The block diagram of FIG. 1 shows a schematic configuration of the wireless communication system 1 according to the first embodiment. The wireless communication system 1 includes a transmitter 100 that transmits a millimeter wave signal and a receiver 200 that receives the millimeter wave signal transmitted by the transmitter 100.

  A transmitter 100 includes a light source 101 for generating an optical subcarrier signal, a baseband amplifier 102, an optical modulator 103, a photodiode 104 with a millimeter wave amplifier, a monitoring photodiode 105, a feedback circuit 106, a DC voltage, and the like. A source 107, a transmission antenna 108, and a synthesizer 109 are provided.

  The receiver 200 includes a reception antenna 201, a millimeter wave detector 202, a coupler 203, a high-pass filter 204, a baseband amplifier 205, a low-pass filter 206, a narrow-band amplifier 207, and a spectrum analyzer 208. Note that the transmitting antenna 108 and the receiving antenna 201 use, for example, highly directional Gaussian optical lens antennas having a beam width of 1 degree or less.

  Hereinafter, the operation of each block in the wireless communication system will be described.

  On the transmitter 100 side, the optical subcarrier signal generation light source 101 generates an optical subcarrier signal that is intensity-modulated at the frequency of the millimeter wave signal as a carrier wave. The baseband amplifier 102 receives and amplifies an input of a data signal to be transmitted and receives an input of a low-frequency power detection frequency signal generated by the synthesizer 109.

  The optical modulator 103 intensity-modulates the optical subcarrier signal with the data signal amplified by the baseband amplifier 102. For example, a Mach-Zehnder type LN modulator may be used as the optical modulator. By the way, the optimum bias voltage of such an optical modulator fluctuates due to time change or temperature change. If the bias voltage deviates from the optimum value when the data signal is modulated, the modulation degree of the optical signal is lowered, and the waveform of the output optical signal is distorted. As a result, in order to obtain error-free transmission in the receiver 200, a larger received light power is required. Therefore, the transmitter 100 adjusts the bias voltage applied to the optical modulator 103 to an optimum value so that the modulation degree of the optical modulator is maximized.

  As shown in FIG. 2, while a data signal is input to the baseband amplifier 102, a signal with a power detection frequency that is lower than the band of the data signal is input to the gain adjustment terminal of the baseband amplifier 102. Here, a sine wave of about 1 kHz is input as the power detection frequency. As a result, it is possible to multiplex the data signal component and the signal component of the low frequency power detection frequency. Further, a part of the output of the optical modulator 103 is branched and input to the monitoring photodiode 105. The monitoring photodiode 105 converts the optical signal into an electrical signal. Further, the feedback circuit 106 adjusts the output of the DC voltage source 107 so that the signal component of 1 kHz is always maximized, and feeds back the optimum bias voltage to the optical modulator 103. As described above, the optical modulator 103 includes a circuit for adjusting the bias voltage. Here, the power detection frequency signal is also used for adjusting the modulation degree of the optical modulator.

  As a result, the optical signal output from the optical modulator 103 is intensity-modulated with a power detection frequency signal of 1 kHz in addition to the data signal. This optical signal is further photoelectrically converted by the photodiode of the photodiode 104 with millimeter wave amplifier, amplified by the millimeter wave amplifier, and radiated from the transmitting antenna 108. In this way, the millimeter wave signal is modulated with the frequency signal for power detection lower than the frequency components of the optical subcarrier signal and the data signal using the bias voltage automatic adjustment mechanism of the optical modulator.

  Next, on the receiver 200 side, as shown in FIG. 1, the millimeter wave signal received by the receiving antenna 201 is demodulated by the millimeter wave detector 202. The demodulated millimeter wave signal is branched by the coupler 203. On one transmission line, only the data signal component is extracted by the high-pass filter 204 and the baseband amplifier 205. On the other transmission line, a signal component of 1 kHz is extracted by the low-pass filter 206, amplified by the narrowband amplifier 207, and then the intensity is measured by the spectrum analyzer 208. As a result, the intensity of the millimeter wave signal can be estimated based on the measured intensity. Therefore, even if the intensity of the millimeter wave signal is small due to noise or the like, the output of the conventional millimeter wave detector is reduced. A higher S / N is obtained than when the DC component is measured. As a result, millimeter wave signals can be detected with high sensitivity.

  When the antenna is installed, for example, referring to the monitor voltage output from the spectrum analyzer, the stepping motor is scanned so that the value of the monitor voltage becomes large, and the position of the pan head that supports the reception antenna of the receiver 200 is determined. Move. In this way, the orientation of the antenna can be adjusted in a short time according to the intensity of the millimeter wave signal. Further, with such a configuration, the antenna orientation can be adjusted without stopping the data transmission even when the antenna is misaligned during the data transmission. In addition, if the transmitter can be used to refer to the monitor voltage and the antenna orientation can be detected so that the maximum receiving sensitivity can be obtained, the antenna axis is shifted between the transmitter and the receiver during data transmission. Even if this occurs, the antenna orientation can be adjusted by both the transmitter and the receiver without stopping data transmission.

  Therefore, according to the present embodiment, the transmitter transmits a millimeter wave signal intensity-modulated at a power detection frequency lower than the frequency of the millimeter wave as a carrier wave, and the receiver extracts the power extracted from the received millimeter wave signal. The intensity of the signal component of the detection frequency is measured, and the intensity of the millimeter wave signal is estimated based on the measured intensity. Thereby, even when the intensity of the millimeter wave signal is small due to noise or the like, the S is higher than that in the case of measuring the DC voltage output from the millimeter wave detector according to the intensity of the received millimeter wave signal in the prior art. Since / N is obtained, reception sensitivity is improved. Therefore, the antenna orientation can be adjusted in a short time when the antenna is installed. Further, even when the antenna axis is deviated during data transmission, the antenna orientation can be adjusted without stopping the data transmission.

  Further, according to the present embodiment, the transmitter transmits a millimeter wave signal modulated with a power detection frequency lower than the frequency of the data signal to be transmitted, and the receiver uses the data signal component and the power detection signal. It becomes possible to separate the signal component of the frequency. In this embodiment, the power detection frequency is 1 kHz. However, the power detection frequency is not limited to this as long as the data signal component and the signal component of the power detection frequency are low enough to be separated. Absent.

  Furthermore, according to the present embodiment, the transmitter receives the input of the frequency signal for power detection by the baseband amplifier, and the intensity of the optical subcarrier signal as a carrier wave is the data signal amplified by the baseband amplifier by the optical modulator. By modulating, it is possible to modulate the millimeter wave signal with the frequency signal for power detection lower than the frequency component of the optical subcarrier signal and the data signal by using the bias voltage automatic adjustment mechanism of the optical modulator. .

[Second Embodiment]
Next, a radio communication system according to the second embodiment will be described. The basic configuration of this wireless communication system is the same as that described in the first embodiment. Below, it demonstrates centering on a different point from 1st Embodiment.

  The difference from the first embodiment is that, as shown in the block diagram of FIG. 3, in the transmitter 300, the millimeter wave signal photoelectrically converted by the photodiode 104a is input to the gain adjustment terminal by the millimeter wave amplifier 104b. The intensity modulation is performed using the low frequency power detection frequency signal. Again, a 1 kHz sine wave signal is input to the gain adjustment terminal as the power detection frequency. Although the modulation band of the gain adjusting terminal is not high, it can be modulated at a low frequency of about 1 kHz.

  Therefore, according to the second embodiment, the transmitter 300 generates a millimeter wave signal as a carrier wave by the light source 101 for generating an optical subcarrier signal, and data to be transmitted by the optical modulator 103. The intensity is modulated with the signal, and the intensity of the millimeter wave signal photoelectrically converted by the photodiode 104a is modulated with the signal of the power detection frequency using the gain adjustment terminal of the millimeter wave amplifier 104b. As a result, the millimeter wave signal can be modulated with the frequency signal for power detection lower than the frequency component of the millimeter wave signal and the data signal as the carrier wave, so that the same effect as the first embodiment can be obtained. It becomes possible.

  In the present embodiment, the transmitter 300 generates a millimeter wave signal as a carrier wave by the light source 101 for generating an optical subcarrier signal, and a data signal to be transmitted by the optical modulator 103. Although it is configured to intensity-modulate, it is not limited to this, as long as it is a configuration capable of generating a millimeter-wave signal as a carrier wave and intensity-modulating with a data signal to be transmitted, For example, even if the transmitter is configured using a millimeter wave signal generation circuit that generates a millimeter wave by an electrical method without using a light source for generating an optical subcarrier signal, the same effect as the above embodiment can be obtained. it can.

[Third Embodiment]
Next, a radio communication system according to the third embodiment will be described. The basic configuration of this wireless communication system is the same as that described in the first embodiment. Below, it demonstrates centering on a different point from 1st Embodiment.

  The difference from the first embodiment is that, as shown in the block diagram of FIG. 4, the receiver 400 extracts the data signal component and the signal component of the power detection frequency from the millimeter wave signal demodulated by the millimeter wave detector 202. It is a point provided with the bias T401 which has the output terminal which extracts and outputs each. Here, the bias T401 outputs a data signal having a frequency component of 10 kHz or more from which the DC component is cut off from one output terminal. From the output terminal to which the other inductor is connected, a signal having a frequency for power detection of 1 kHz is output. Since the number of parts can be reduced by using the bias T401 in this way, a compact receiver can be configured.

  Therefore, according to the third embodiment, in the receiver 400, the data signal component and the signal component of the power detection frequency are extracted from the millimeter wave signal demodulated by the millimeter wave detector, and output terminals for outputting the data signal component and the signal component are output. With the configuration including the bias T401, the number of components can be reduced and the receiver can be made compact in addition to the effects according to the first embodiment.

[Fourth Embodiment]
Next, a radio communication system according to the fourth embodiment will be described. The basic configuration of this wireless communication system is the same as that described in the first embodiment. Below, it demonstrates centering on a different point from 1st Embodiment.

  The difference from the first embodiment is that, as shown in the block diagram of FIG. 5, the receiver 500 detects a signal component passed through the filter circuit, and the signal component output by the detector 501. And a voltmeter 502 for measuring the voltage value.

  Here, after a signal in a frequency band for power detection is amplified by the narrowband amplifier 207, a 1 kHz signal that has passed through the bandpass filter 209 is input to the detector 501. Then, a DC voltage is output according to the intensity of the signal component detected by the detector 501, and the value of the output voltage is measured by the voltmeter 502. By using the detector that measures the signal strength of 1 kHz in this way, it becomes possible to detect the received power without using an expensive spectrum analyzer, and thus it is possible to configure an inexpensive receiver. Become.

  Therefore, according to the fourth embodiment, in the receiver 500, after the millimeter wave signal demodulated by the millimeter wave detector 202 is branched by the coupler 203, the power passed through the bandpass filter 209 by the detector 501. In addition to the effect according to the first embodiment, the signal component in the detection frequency band is detected and the voltage value of the signal component output from the detector is measured by the voltmeter 502. Therefore, the receiver can be configured at a lower cost than the configuration using an expensive analyzer. Although the coupler 203 is used in the present embodiment, a configuration using a bias T may be used as in the third embodiment.

[Fifth Embodiment]
Next, a radio communication system according to the fifth embodiment will be described. The basic configuration of this wireless communication system is the same as that described in the first embodiment. Below, it demonstrates centering on a different point from 1st Embodiment.

  The difference from the first embodiment is that the millimeter wave detector 601 that demodulates the millimeter wave signal received by the receiving antenna 201 in the receiver 600 is demodulated by the demodulated millimeter wave signal as shown in the block diagram of FIG. A data signal output terminal for outputting a data signal from the terminal and a monitor voltage output terminal for outputting a monitor voltage corresponding to the intensity of the received millimeter wave signal.

  Normally, the monitor output voltage terminal of the millimeter wave detector 601 can output not only a DC voltage but also a low frequency AC signal component. Here, a 1 kHz signal having a power detection frequency is output as a monitor voltage from the monitor voltage output terminal. By measuring this monitor voltage, the intensity of the received millimeter wave signal is estimated. With such a configuration, a compact receiver is configured.

  Therefore, according to the fifth embodiment, in the receiver, the millimeter wave detector that demodulates the received millimeter wave signal includes an output terminal that outputs a data signal from the demodulated millimeter wave signal, and the received millimeter wave signal. And an output terminal that outputs a monitor voltage in accordance with the intensity of the power, and a configuration that extracts the signal component of the power detection frequency from the terminal that outputs the monitor voltage relates to the first embodiment. In addition to the effect, the number of parts can be reduced compared to the configuration using the coupler, and the receiver can be made compact.

1 is a block diagram showing a schematic configuration of a radio communication system according to a first embodiment. It is a figure for demonstrating the intensity | strength modulation using the bias voltage adjustment mechanism of an optical modulator in the said radio | wireless communications system. It is a block diagram which shows schematic structure of the radio | wireless communications system which concerns on 2nd Embodiment. It is a block diagram which shows schematic structure of the radio | wireless communications system which concerns on 3rd Embodiment. It is a block diagram which shows the schematic structure of the radio | wireless communications system which concerns on 4th Embodiment. It is a block diagram which shows the schematic structure of the radio | wireless communications system which concerns on 5th Embodiment. It is a block diagram which shows the schematic structure of the conventional radio | wireless communications system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wireless communication system 100 ... Transmitter (Example 1)
DESCRIPTION OF SYMBOLS 101 ... Light source 102 for optical subcarrier signal generation ... Baseband amplifier 103 ... Optical modulator 104 ... Photodiode with millimeter wave amplifier 105 ... Photodiode for monitoring 106 ... Feedback circuit 107 ... DC voltage source 108 ... Transmission antenna 109 ... Synthesizer 200 ... Receiver (Example 1)
201 ... reception antenna 202 ... millimeter wave amplifier 203 ... coupler 204 ... high pass filter 205 ... baseband amplifier 206 ... low pass filter 207 ... narrow band amplifier 208 ... spectrum analyzer 209 ... band pass filter 300 ... transmitter (Embodiment 2)
104a ... Photodiode 104b ... Millimeter wave amplifier 400 ... Receiver (Example 3)
401: Bias T
500 ... Receiver (Example 4)
501: Detector 502 ... Voltmeter 600 ... Receiver (Example 5)
601 ... Millimeter wave detector 700 ... Transmitter (conventional example)
800 ... Receiver (conventional example)

Claims (7)

A wireless communication system comprising a transmitter for transmitting a millimeter wave signal and a receiver for receiving a millimeter wave signal transmitted by the transmitter,
The transmitter is
A light source for generating an optical subcarrier signal that generates an optical subcarrier signal whose intensity is modulated at a frequency of a millimeter wave signal as a carrier wave ;
While amplifying the data signal to be transmitted and having a gain adjustment terminal, by inputting a power detection frequency signal having a frequency lower than that of the data signal to be transmitted to the terminal, the data signal is converted to the power detection frequency. A baseband amplifier that modulates the signal,
An optical modulator for intensity-modulating the optical subcarrier signal with a data signal amplified by the baseband amplifier and modulated with the power detection frequency signal;
A photodiode for converting an optical signal intensity-modulated by the optical modulator into an electrical signal;
A transmission antenna that transmits an electrical signal photoelectrically converted by the photodiode as a millimeter wave signal;
A monitoring photodiode that outputs a signal branched from an optical signal whose intensity is modulated by the optical modulator, and that outputs an electrical signal; a DC voltage source that applies a bias voltage to the optical modulator; and A bias adjustment circuit comprising a feedback circuit for receiving an output and adjusting an output of the DC voltage source;
With
The power detection frequency signal is also used to adjust the modulation degree of the optical modulator in the bias adjustment circuit,
The receiver
Wireless communication system according to claim <br/> measuring its intensity from the received millimeter-wave signal by extracting a frequency signal for the power detection. A wireless communication system comprising a transmitter for transmitting a millimeter wave signal and a receiver for receiving a millimeter wave signal transmitted by the transmitter,
The transmitter is
A millimeter wave signal generation circuit that generates a millimeter wave signal as a carrier wave and intensity-modulates the millimeter wave signal with a data signal to be transmitted;
And the millimeter wave amplifier for intensity modulated by the millimeter wave signal frequency signal for power detection of the low frequency than the data signal the to be transmitted output millimeter-wave signal is input to the gain adjustment terminal from the generator circuit,
A transmitting antenna for transmitting a millimeter wave signal output from the millimeter wave amplifier;
Equipped with a,
The receiver
Radio communications system that is characterized by measuring the intensity from the received millimeter-wave signal by extracting a frequency signal for the power detection. The receiver
  A receiving antenna for receiving the millimeter wave signal;
  A millimeter wave detector for demodulating the millimeter wave signal received by the receiving antenna;
  A coupler for branching the millimeter wave signal demodulated by the millimeter wave detector;
  A filter circuit for extracting a power detection frequency signal from one of the millimeter wave signals branched by the coupler;
  A narrowband amplifier that amplifies and outputs the power detection frequency signal extracted by the filter circuit;
  Means for measuring the strength of the frequency signal for power detection output from the narrowband amplifier;
  Means for extracting a data signal from the other millimeter wave signal branched by the coupler;
  The wireless communication system according to claim 1, further comprising: The receiver
A receiving antenna for receiving the millimeter wave signal ;
A millimeter wave detector for demodulating the millimeter wave signal received by the receiving antenna;
A bias T having an output terminal to which the millimeter wave detector extracts the frequency signal data signal及 beauty power detection from the millimeter wave signal demodulated outputs respectively,
Means for measuring the intensity of the frequency signal for power detection extracted by the bias T;
The wireless communication system according to claim 1, further comprising: The receiver
A receiving antenna for receiving the millimeter wave signal ;
A millimeter wave detector for demodulating the millimeter wave signal received by the receiving antenna;
A coupler for bifurcation millimeter wave signal the millimeter wave detector is demodulated,
One of the millimeter wave signals branched by the coupler is input, a narrowband amplifier that amplifies and outputs a signal in the frequency band of the power detection frequency signal ;
A filter circuit that receives the output of the narrowband amplifier and passes a power detection frequency signal;
A detector for detecting a signal component passed by the filter circuit;
A voltmeter for measuring a voltage value of a signal component output by the detector;
Means for extracting a data signal from the other millimeter wave signal branched by the coupler;
The wireless communication system according to claim 1, further comprising: The receiver
A receiving antenna for receiving the millimeter wave signal ;
While demodulating the millimeter wave signal received by the receiving antenna ,
An output terminal for outputting a data signal from the demodulated millimeter wave signal;
An output terminal for outputting a monitor voltage according to the intensity of the received millimeter wave signal;
And Bei example, millimeter wave detector which outputs a frequency signal power detection from the terminal that outputs the monitor voltage as a monitor voltage,
Means for measuring the intensity of the frequency signal for power detection output from the terminal for outputting the monitor voltage of the millimeter wave detector;
The wireless communication system according to claim 1, further comprising: The transmitter and receiver are:
The radio communication system according to any one of claims 1 to 6 , wherein millimeter-wave signals are transmitted and received using an antenna having a high directivity with a beam width of 1 degree or less.

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