JPH05327660A - Spread spectrum transmission and reception system - Google Patents

Abstract

PURPOSE:To reduce the cost of the reception system by forming a reception section with a narrow band circuit so as to use a spread modulator and a correlation device in common for the transmission and reception. CONSTITUTION:A signal modulation section 21 modulates an information signal and the modulated signal is inputted to a waveguide section of a horn antenna 1 via a changeover device 2 to excite an electromagnetic wave and a spread code generator 16 generates a spread code and inputted to a power supply changeover device 18 via a changeover device 17, the polarity of a power supply is switched in response to the spread code and the result is inputted to a polarizer provided to the waveguide section. Then the polarizer converts the electromagnetic wave into two orthogonal linearly polarized waves, they are set, and at the reception, a spread code generating section 23 generates a reception spread code and it is inputted to a power supply changeover device 18 via the changeover device 17, the polarity of the power supply is switched in response to the spread code and inputted to the polarizer. Then the polarizer converts the linearly polarized wave introduced to the waveguide section into an electromagnetic wave having one polarized wave front and it is spread and demodulated and the signal subject to spread demodulation is inputted to a signal demodulation section 22 via a changeover device 2, in which the signal is demodulated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum transmission / reception system used in the microwave and millimeter wave bands.
A spread spectrum transmission / reception system is a communication system that transmits a baseband information signal by expanding it to a bandwidth that is several hundred to several thousand times the bandwidth of the baseband information signal. Modulates a spread code signal to expand the bandwidth, allocates a spread code signal to a number of wireless stations, and from one wireless station to a desired wireless station among other wireless stations. To be able to send.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of an electric circuit of a conventional spread spectrum transmission / reception system. A transmission section 31 and a reception section 41 are provided and a transmission / reception antenna 3 is provided via a switch 2.
0, and in the transmitter 31, in the modulator 4, the input terminal 5
The data such as voice, image, etc., which is inputted via the signal is modulated, the information modulated wave is outputted and inputted to the spread modulator 32. At the spread modulator 32, the spread code signal inputted from the spread code generator 33 is used. The information-modulated wave is modulated and output as a spread-modulated wave, output via the power amplifier 3, and the switch 2 is switched to transmit from the antenna 30. If the band width of the spread code signal is selected to be wider than the frequency band width of the information modulated wave, a spread modulated wave having a wider band than that of the information modulated wave is obtained. In the receiving unit 41, the spread modulated wave received by the receiving antenna via the switch 2 is amplified by the wide band low noise amplifier 34 to an appropriate level and output, and the band filter 35 removes the image frequency band, The mixer 36 mixes with the signal input from the local oscillation circuit 37, converts the signal into an intermediate frequency signal and outputs the intermediate frequency signal, which is amplified by a wide band amplifier 38 to an appropriate level and input to a correlator 39.

The spread code generator 40 outputs the spread code signal given to the receiver and inputs it to the correlator 39.
In the correlator 39, the spread modulated wave input from the wide band amplifier 38 is spread and demodulated and output as an information modulated wave, which is input to the demodulator 12 via the narrow band filter 10 and the amplifier 11, and the demodulator 12 The information modulated wave is demodulated by the output terminal 13
Outputs data such as voice and image demodulated via.
The information modulated wave input to the demodulator 12 is branched and input to the synchronization control circuit 14, the synchronization control circuit 14 outputs a clock signal synchronized with the spread modulation wave, and input to the spread code generator 40. The spread code generator 40 outputs a spread code signal synchronized with the spread modulated wave input by the clock signal.

[0004]

Therefore, since the bandwidth of the received signal is expanded in the receiver 41, the correlator 3
It is necessary to configure the input circuits up to 9 with a circuit having a flat frequency characteristic over a wide band, and since the received signal has a wide band, it is not possible to freely select the intermediate frequency. The present invention enables the receiving unit to be configured by a narrow band circuit, expands the degree of freedom in selecting an intermediate frequency, and enables transmission and reception by using a spread modulator and a correlator as well, thereby reducing the cost. It is an object of the present invention to provide a general spread spectrum transmission / reception system.

[0005]

FIG. 1 is an electric circuit block diagram of a spread spectrum transmission / reception system showing an embodiment of the present invention. As shown in FIG. Polarization-switchable ferrite polarizer provided in the waveguide section, a signal modulation section 21 for modulating an information signal to output an information modulated wave, and an input / output for inputting / outputting a signal to / from the waveguide section of the horn antenna. Means, a spread code generator 16 for transmission for generating a spread code signal, and a power source switch 18 for switching the polarity of the power source and outputting the signal.
The information modulated wave from the No. 1 is input to the waveguide section via the input / output means, the electromagnetic wave is excited in the waveguide section, and the spread code signal from the spread code generator for transmission 16 is switched to the power source. 1
8, the polarity of the power source is switched according to the spread code signal input by the power source switching device 18 and is output to the polarizer, and the electromagnetic wave has two orthogonal polarization planes by the polarizer. It is converted to linearly polarized wave and transmitted.

At the time of reception, the ferrite type polarizer, the input / output means, the signal demodulation section 22 for demodulating the signal extracted from the input / output means, and the reception spread code generation section 23 for generating the spread code signal. , The power source switching unit 18, and introduces the linearly polarized wave having the two orthogonal polarization planes into the waveguide section of the horn antenna to receive the spread code signal for reception from the spread code generator for reception 23. It is input to the power supply switching device 18, the polarity of the power supply is switched according to the spread code signal input by the power supply switching device 18 and output to the polarizer, and the linear polarized light is polarized by the polarization device. The signal is converted into an electromagnetic wave having a wavefront and input to the signal demodulation unit 21 through the input / output unit, and the signal demodulation unit 21 demodulates the signal and receives the signal. Also, the switching device 2
And 17 are provided to connect the signal modulation unit 21 and the signal demodulation unit 22 to the input / output unit via the switch 2, and the transmission spreading code generator 16 and the receiving spreading code generation unit 23 are provided. May be connected to the power source switching unit 18 via the switching unit 17 so that transmission and reception can be performed by switching between the switching unit 2 and the switching unit 17.

[0007]

In the present invention, a ferrite type polarizer is provided in the waveguide part of the horn antenna, the transmitter is used as a diffusion modulator during transmission, and the information modulated wave is linearly polarized with two orthogonal polarization planes. To transmit as a spread-modulated wave and use the same polarizer as a correlator at the time of reception to convert a linearly polarized wave having two orthogonal polarization planes into an electromagnetic wave having one polarization plane. The information demodulated wave is diffused and demodulated, the information modulated wave is taken out from the waveguide, and the demodulated circuit demodulates the information modulated wave, so that the polarizer can be used as both a spread modulator and a correlator. Since the signal diffused and demodulated by the polarizer is demodulated by the demodulator circuit, the demodulator circuit can be configured with a narrow band circuit and the degree of freedom in selecting the intermediate frequency can be increased. Can.

[0008]

1 is a block diagram of an electric circuit of a spread spectrum transmission / reception system showing an embodiment of the present invention.
In the figure, the same components as those shown in FIG. 3 are designated by the same symbols. As shown in FIG. 2, reference numeral 1 denotes a horn antenna. As shown in FIG. And has a structure. Reference numeral 2 is a switcher, one end of which is connected to a signal input / output unit for the waveguide section and the other end of which is used as two switchable terminals, and the signal modulating section 21 is connected to one of the terminals. The signal demodulation section 22 is connected to the other side, and the switch 2 is switched so that the signal from the signal modulation section 21 is input to the input / output means at the time of transmission, and from the input / output means to the signal demodulation section 22 at the time of reception. The signal is input. First, the signal processing at the time of transmission will be described. In the signal modulator 21, the information signal inputted from the input terminal 5
M-modulated or FM-modulated and output as an information-modulated wave, power-amplified by an amplifier 3 and output, and input to a signal input / output unit provided in a waveguide section of the horn antenna 1 via a switch 2. Then, the input / output means excites electromagnetic waves in the waveguide section.

Reference numeral 17 is a switching device, one end of which is an input side,
The other end is used as an output side, the output side allows a signal to be input to the power source switching device 18, two terminals are provided on the input side, and one of the terminals is connected to the transmission spreading code generator 16. The reception spreading code generator 23 is connected to the other terminal. At the time of transmission, operate the switching device 17,
The spread code generated by the transmission spread code generator 16 is input to the power supply switch 18 via the switch 17. The spreading code generator 16 for transmission outputs a PN code or a Gold code, which is faster than the information signal, as a spreading code signal. The power supply switching unit 18 has a positive power supply input to the input terminal 19 and a negative power supply input to the input terminal 20, and switches the polarity of the power supply according to the spread code input from the transmission spread code generator 16. Output and input to a ferrite type polarizer provided in the waveguide section of the horn antenna 1, the electromagnetic wave excited by the input / output means by the polarizer is converted into a linear polarized wave having two orthogonal polarization planes, and spread modulation is performed. The horn antenna 1 transmits a spread modulated wave as a wave.

Next, the signal processing at the time of reception will be described. In the signal processing described at the time of transmitting, the spread modulated wave transmitted from another wireless station is received by the horn antenna 1,
The diffuse modulation wave is guided to the ferrite type polarizer provided in the waveguide portion of the horn antenna 1. Switch 17
By operating the, the spread code from the reception spread code generator 23 is input to the power supply switch 18 via the switch 17, and the power supply switch 18 changes the polarity of the power supply according to the input spread code. The output is switched and input to a ferrite type polarizer provided in the waveguide section of the horn antenna 1, and the linearizer converts the linearly polarized wave of the diffusion modulated wave into an electromagnetic wave (information modulated wave) having one polarization plane. The input / output unit converts the electromagnetic wave into an electric signal of an information modulated wave and outputs the electric signal. The information modulated wave is input to the signal demodulation section 22 by operating the switch 2, and the information demodulated section 22 demodulates the information modulated wave.

The signal demodulation section 22 amplifies the input information modulated wave to an appropriate level by the narrow band low noise amplifier 6 and outputs it. The narrow band filter 7 removes the image frequency band and the mixer. At 8, the signal is mixed with the signal input from the local oscillation circuit 9 and converted into an intermediate frequency signal for output. The information-modulated wave input to the mixer 8 is a narrow band signal after spread demodulation, so that the intermediate frequency can be set freely. The intermediate frequency signal output from the mixer 8 is
Remove unnecessary noise components with narrow band filter 10
Similarly, the narrow band amplifier 11 amplifies the signal to an appropriate level, branches the amplified signal, inputs one to the demodulator 12, and inputs the other to the receiving spread code generator 23, and the demodulator 1
In step 2, the data such as voice and image is output after being demodulated by AM or FM and demodulated through the output terminal 13. The reception spread code generator 23 inputs the input information modulated wave to the synchronization control circuit 14, outputs a clock signal synchronized with the spread modulation wave received by the synchronization control circuit 14, and generates a reception spread code. And outputs the spread code signal assigned to this radio in synchronism with the spread modulated wave received by the spread code generator for reception 15 with the clock signal, and switches the power supply through the switch 17. Input to the container 18.

FIG. 2 is a block diagram showing an embodiment of the horn antenna 1 of FIG. In the horn antenna 1, one end of a circular waveguide 25 is used as a horn-shaped opening 24 so that an electromagnetic wave can be emitted or received. Two
Reference numeral 6 denotes a ferrite type polarizer, which has a structure in which an exciting coil is wound around a ferrite rod, the center of the ferrite rod is aligned with the tube axis of the circular waveguide 25, and the longitudinal direction of the ferrite rod is parallel to the tube axis. Are arranged as follows. Ferrite polarizer 26 and end face 28 of circular waveguide 25
From the side surface of the circular waveguide 25 between the excitation probe 27
And the excitation probe 27 is used as a signal input / output means for the circular waveguide 25. The spread code input to the power supply switching unit 18 is a pulse signal of 1 and 0, and a pulse signal faster than the information signal is used. The power supply switching unit 18 uses the polarity of the power supply according to the input spread code. Is switched and output, and is input to the excitation coil of the ferrite type polarizer provided in the waveguide section of the horn antenna 1. At the time of transmission, the electromagnetic wave excited by the excitation probe 27 is transmitted by the polarizer 26.
The polarized wave is converted into a linearly polarized wave having two orthogonal polarization planes, radiated from the opening 24, and at the time of reception, the electromagnetic wave received by the opening 24 is converted into an electromagnetic wave (information modulated wave) having one polarization plane by the polarizer 26. After conversion, the same electromagnetic wave is coupled to the probe 27, converted into an electric signal, and output as an information modulated wave.

[0013]

As described above, according to the present invention,
Utilizing the ferrite type polarizer provided in the waveguide part of the horn antenna, it is used as a diffusion modulator during transmission,
Since it can also be used as a correlator at the time of reception, the signal is extracted from the waveguide section by spreading demodulation with the same polarizer, and the signal is demodulated with the demodulation circuit. Since it can be configured with a band circuit, and the frequency of the spread demodulated signal is converted, the intermediate frequency can be freely set, and the cost is reduced and the spectrum is economical. A spread type transmission / reception system can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram of an electric circuit of a spread spectrum transmission / reception system showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of the horn antenna of FIG.

FIG. 3 is a block diagram of an electric circuit of a spread spectrum transmission / reception system showing a conventional example.

[Explanation of symbols]

 1 Horn Antenna 2 Switcher 3 Amplifier 4 Modulator 5 Input Terminal 6 Amplifier 7 Bandpass Filter 8 Mixer 9 Local Oscillator 10 Bandpass Filter 11 Amplifier 12 Demodulator 13 Output Terminal 14 Synchronization Control Circuit 15 Spreading Code Generation for Reception Device 16 Transmission spreading code generator 17 Switching device 18 Power supply switching device 19 Input terminal 20 Input terminal 21 Signal modulation unit 22 Signal demodulation unit 23 Reception spreading code generation unit 24 Opening 25 Waveguide 26 Polarizer 27 Probe 28 Termination surface 30 Antenna 31 Transmitter 32 Spreading Modulator 33 Spreading Code Generator 34 Amplifier 35 Bandpass Filter 36 Mixer 37 Local Oscillator 38 Amplifier 39 Correlator 40 Spreading Code Generator 41 Receiver

Claims (3)

[Claims] 1. A ferrite type polarizer capable of polarization switching provided in a waveguide section of a horn antenna, a signal modulating section for modulating an information signal to output an information modulated wave, and a waveguide section of the horn antenna. It comprises an input / output means for inputting / outputting a signal, a transmission spreading code generator for generating a spreading code signal, and a power source switching device for switching the polarity of a power source and outputting the same. Input to the waveguide through the input / output means to excite electromagnetic waves in the waveguide, and input the spread code signal from the transmission spread code generator to the power switch to supply the same power. The polarity of the power source is switched according to the spread code signal input by the switcher, output, and input to the polarizer, and the electromagnetic wave is converted into a linearly polarized wave having two orthogonal polarization planes and transmitted. Spec that is characterized by Toll spread transmission / reception system. 2. The ferrite type polarizer, the input / output unit, a signal demodulation unit for demodulating a signal extracted from the input / output unit, a reception spreading code generating unit for generating a spreading code signal, and the power source switching. A linearly polarized wave having two orthogonal polarization planes is introduced into the waveguide section of the horn antenna, and the spread code signal for reception from the spread code generator for reception is input to the power source switching unit. Then, the polarity of the power source is switched according to the spread code signal input by the power source switching device, output and input to the polarizer, which converts the linearly polarized wave into an electromagnetic wave having one polarization plane. Input to the signal demodulation unit via the input / output unit,
The spread spectrum transmission / reception system according to claim 1, wherein the signal demodulator demodulates the signal and receives the signal. 3. The signal modulation section and the signal demodulation section are connected to the input / output means via a first switch, and the transmission spreading code generator and the reception spreading code generating section are secondly connected. The spread spectrum type according to claim 1 or 2, wherein transmission and reception are enabled by connecting to the power source switching device via a switching device and switching between the first switching device and the second switching device. Transmission and reception system.