JP2000013342A - Radio transmitter, radio receiver and radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent easy suffering of the disturbance to communication without complicating the constitution and to increase the range of communication by converting the modulated signals or secondary modulating signals via an impulse string signal in terms of frequency to scatter the converted signals as plural frequency signals for radio communication, integrating the frequency signals via an envelope detection circuit in terms of time at the receiving side to perform synthesizing of signals and relatively improving the S/N ratio. SOLUTION: A switch circuit SW switches the output of a BPF 1 or BPF 2 in response to a transmission code to perform radio communication. Meanwhile, the BPF 1 and BPF 2 of the receiver side have the characteristics of the central frequency and the pass-band width which are equal to those of the BPF 1 and BPF 2 of the transmitter side. Two envelope detection circuits perform the envelope detection of outputs of the BPF 1 and BPF 2 respectively. Each of both envelope circuits has a circuit which rectifies the input signals, a filter circuit which filters the rectified signals with a prescribed time constant via a capacitor, etc., and a circuit which discharges the charged electric charge of the capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio transmitter, a radio receiver, and a radio communication system using weak radio waves.

[0002]

2. Description of the Related Art A "radio station having a remarkably weak radio wave" (hereinafter referred to as a "low radio wave radio device") defined in Article 6 of the Radio Law can be used without a license. (A device that unlocks and unlocks a lock wirelessly without using a key) and various simple remote control systems.

[0003] However, since the weak radio wave radio device has an extremely low allowable transmission output, the reception circuit RF
The carrier-to-noise ratio (CN ratio) at the stage is low. The signal-to-noise ratio is closely related to demodulated signal-to-noise (SN ratio), communication reliability (bit error rate), communication distance, and the like. Is short ".

[0004] Generally, the occupied band of a wireless device is restricted from the viewpoint of effective use of frequency, and a single frequency band is usually used. On the other hand, the weak radio radio device does not have the occupied band limitation, but has a strictly reduced allowable output as compared with a general radio device.

[0005] For this reason, the weak radio apparatus is inherently susceptible to communication disturbance and has a problem that the communication distance is short.

The configuration of a wireless device using a weak radio wave is the same as that of a general wireless device, and a technology for preventing communication disturbance applied to a general wireless device and a technology for extending a communication distance are applied to a weak radio wireless device. Can also be employed. For example, an attempt has been made to improve the SN ratio by narrowing the communication band or spreading the spectrum.

[0007]

However, if the communication band is narrowed, noise is eliminated and the CN ratio is improved, but at the same time, the upper limit of the data transmission rate is reduced.

[0008] According to the method of spreading a signal on the frequency axis, the CN ratio is improved by the spreading gain. As a spreading method, there are a DS (direct spreading) method and an FH (frequency hopping) method. When the former is applied to a weak radio wave radio device, the frequency distribution density is high, and according to the provisions of Article 6, Paragraph 2 of the Radio Law Enforcement, the allowable transmission power is further reduced, and the CN ratio gained by the spreading gain is offset. Would. In the latter case, the carrier synchronization pull-in time and the code synchronization pull-in time are required, and the real-time property is impaired. Further, in both cases, the circuit scale for the PN code processing and the synchronization acquisition processing becomes large, so that the incorporation into equipment is reduced.

[0009] For these reasons, the weak radio wave radio device is poor in versatility and its use range is limited.

An object of the present invention is to make use of the degree of freedom of the occupied band of a weak radio wave radio device, make it less susceptible to communication disturbance without complicating the configuration, and extend the communication distance. And an apparatus used for the same.

[0011]

A radio communication system according to the present invention utilizes the characteristic of weak radio waves, in which the allowable output is strictly suppressed as compared with a general radio station, but the occupied band is not limited. Then, by performing wireless communication using a plurality of frequency bands simultaneously, the CN ratio is improved, and the above-mentioned problem is solved.

First, the relation of each wireless communication system of the present invention is shown in a tree format in FIG. In the figure, the A method is a method for mainly improving the anti-jamming property,
Each of the B2, C1, and C2 schemes solves the problem of beats that occur secondarily with them.

In the A system, a modulated signal or a sub-modulated signal is frequency-converted with an impulse train signal, dispersed as a plurality of frequency signals, and transmitted by radio. On the receiving side, these signals are integrated temporally by an envelope detection circuit, thereby synthesizing the signals and relatively improving the SN ratio.
Also, a method of modulating the frequency band so as to be divided and used,
A method of modulating the time width of an impulse train, a method of demodulating by counting spectra, and the like are used to improve anti-jamming and improve reliability. In the A method, since a beat unlike the B method described later does not occur in principle, feedback control or the like for canceling the beat is unnecessary, and the circuit configuration can be simplified.

In the B1 system, the local oscillation signal is dispersed into a plurality of frequencies as in the A system by using an impulse train signal. The receiver also performs frequency synthesis by using the impulse train signal as a local oscillation signal, but a beat occurs if there is a deviation in the period of the impulse train signal between the transmitter and the receiver. Therefore, an arbitrary one of the dispersed waves is extracted, and an impulse train signal is reproduced based on the extracted one wave, thereby solving the problem of beat.

In the B2 system, the beat-impulse interval is measured and expanded by paying attention to the fact that the beat generated when the receiver synthesizes the frequency using the impulse train signal as the local oscillation signal becomes impulsive. By performing feedback control as described above, zero beat frequency synthesis is performed.

In the B3 system, the phases of the subcarriers and the carrier are matched by generating the frequencies of the subcarrier and the carrier on the basis of a common reference frequency signal. Then, the sub-modulation signal of the transmission code is frequency-converted with an impulse train signal having a frequency of an integer ratio of the sub-carrier frequency as a fundamental frequency, and wirelessly transmitted. On the receiver side, the frequency component of the subcarrier is extracted, and the fundamental frequency of the impulse train signal is controlled by the PLL based on the frequency of the subcarrier.

In the C1 system, two-wave dispersion transmission is performed by performing one-stage frequency conversion on the transmitter side, and two-wave carrier components are extracted on the receiver side, and the center frequency of the two carrier components is determined. Thus, by reproducing the local oscillation signal, frequency synthesis can be performed without generating a beat.

In the C2 system, the transmitter side synthesizes a local oscillation signal with the dispersion signal to perform radio transmission, and the receiver side extracts the local oscillation signal as a pilot signal and performs frequency synthesis. This enables frequency synthesis without generating beats.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A method "band division modulation / demodulation method"
An example (see FIG. 31) will be described as a first embodiment with reference to FIGS.

FIG. 1A is a block diagram showing the configuration of a transmitter, and FIG. 1B is a block diagram showing the configuration of a receiver. In this example, in the transmitter, a fundamental wave oscillating circuit oscillates a predetermined frequency signal, and an impulse train generating circuit generates an impulse train signal at a period of the fundamental wave frequency. The impulse train generating circuit includes a waveform shaping circuit for shaping the waveform of the fundamental frequency signal, a differentiating circuit for differentiating the waveform-shaped signal, and a blocking oscillation circuit for performing blocking oscillation using the differentiated signal as a trigger. FIG. 2A is an example of a waveform diagram at each stage. The waveform shaping circuit outputs a rectangular wave signal using a comparator or the like, and the differentiating circuit extracts the rising edge. The blocking oscillation circuit generates an impulse signal having a very short pulse width by using the edge signal as a trigger. Therefore, the generation cycle of this impulse signal is equal to the oscillation frequency of the fundamental wave oscillation circuit. If the frequency of the fundamental frequency signal is 1 MHz, line spectra of the same level (a linear spectrum having a narrow width on the frequency axis) appear at intervals of 1 MHz on the frequency axis of the impulse train signal.

As shown in FIG. 1A, the band-pass filter BPF1 has a center frequency of 300 MHz and a pass band width of 9 MHz.
MHz band-pass filter BPF2
Has a characteristic of a center frequency of 310 MHz and a pass bandwidth of 9 MHz, and the switch circuit SW has a BPF1 according to a transmission code.
Alternatively, the output of the BPF 2 is switched and wirelessly transmitted. Here, when the sign is 0, BPF1 is selected, and when the sign is 1, BPF1 is selected.
If the output of the PF2 is selected, as shown in FIG. 2B, when the sign is 0, 295.5 MHz to 30
When the 4.5 MHz component is transmitted and the code is 1, 30
A component of 5.5 MHz to 314.5 MHz will be transmitted.

On the other hand, the band-pass filter BPF on the receiver side
1, BPF2 are band-pass filters BPF1,
It has the same center frequency and passband characteristics as BPF2. The two envelope detection circuits detect the envelopes of the outputs of BPF1 and BPF2, respectively. These envelope detection circuits include a circuit for rectifying the input signal, a smoothing circuit for smoothing the rectified signal with a predetermined time constant using a capacitor or the like, and a circuit for discharging the charge of the capacitor with a predetermined time constant. I have. The response of the envelope detection is determined by the charge time constant and the discharge time constant. The differential amplifier circuit differentially amplifies the output of the envelope detection circuit and reproduces a transmission code. The envelope detection circuit basically includes an integration circuit having a relatively large time constant, and is 296 MHz to 304 Mh output from the BPF 1.
The signal level in the Hz band is extracted as a voltage signal. Similarly, by performing envelope detection on the output signal of BPF2, 3
A signal level voltage of 06 MHz to 314 MHz is generated. Therefore, when "1" and "0" are transmitted as transmission codes from the transmitter, the output level of the envelope detection circuit on the receiver side changes as shown in FIG. As a result, a differential amplification waveform as shown in FIG.

As described above, the predetermined band 296 MHz to 3
Since a plurality of 14 MHz waves are divided into two bands and the bits of the transmission code are transmitted, the probability that each band will be disturbed is halved. Since detection is performed for half of the band, the detection output level is reduced by half, but by finally performing differential amplification, it is possible to obtain an SN ratio equivalent to a case where band division is not performed. As a result, the anti-jamming performance is improved.

Next, an example of the "local oscillation channel control system" of the A system will be described as a second embodiment with reference to FIG. 3 and FIG.

In the example shown in FIG. 1, band division is performed by selecting a pass band. In the second embodiment, band division is performed by frequency shift. In the transmitter shown in FIG. 3A, the cut-off frequency of the low-pass filter LPF is 9.5 MHz, and passes 9 waves of 1 MHz to 9 MHz. The local oscillation circuit switches the local oscillation frequency according to the transmission code. The frequency conversion circuit passes through the LPF 9
The signal of the line spectrum of the wave is frequency-converted by the local oscillation signal. The band pass filter BPF has a center frequency of 305M.
Hz and a pass band width of 19 MHz, and this band is wirelessly transmitted.

FIG. 4A shows the spectrum of the signal of each part in the transmitter. The line spectrum of 9 waves from 1 MHz to 9 MHz is 286 MHz to 2 when the transmission code is 0.
94 MHz lower sideband and 296 MHz to 304 MH
The frequency is converted to the upper waveband of z. Similarly, if the transmission code is 1
306MHz to 314MHz lower sideband and 3
The frequency is converted to an upper waveband of 16 MHz to 324 MHz. Then, the components of the upper sideband of the transmission code “0” and the lower sideband of the transmission code “1” are wirelessly transmitted by the BPF.

On the other hand, on the receiver side, as shown in FIG. 3B, the bandpass filter BPF passes the components of the upper sideband of the transmission code "0" and the lower sideband of the transmission code "1". And one of the two frequency conversion circuits is 295 MHz
And the other frequency conversion circuit converts the frequency using the 315 MHz local oscillation signal. Therefore, as shown in FIG. 4B, if the transmission code is “0” or “1”, the frequency conversion result is 1 MHz.
A line spectrum of 9 waves of ９9 MHz is output. The cutoff frequency of the two low-pass filters LPF is 9.5 MHz, and passes the frequency-converted nine-wave line spectrum. Then, when the transmission code is “0”, FIG.
When the transmission code is "1", the output level of the lower envelope detection circuit in FIG. 3B becomes higher. Thus, the output level of the differential amplifier circuit can be output as a decoded code.

Next, an example of the "1: n communication system" of the A system will be described as a third embodiment with reference to FIGS.

In the example shown in FIG. 3, the transmission is performed using two fixed bands according to the transmission code.
In the third embodiment, a transmitter selectively performs transmission to a plurality of receivers according to a frequency channel. The local oscillation circuit of the transmitter shown in FIG. 5A switches its oscillation frequency according to the transmission code and channel. The band pass filter BPF is provided for each channel. FIG. 6 shows the frequency band of each channel.

The center frequency of the band-pass filter BPF of the receiver shown in FIG. 5B is preset for each channel. Other configurations are the same as those shown in FIG.

By switching the channel on the transmitter side and transmitting the data, 1: n communication can be performed.

Next, an example of the "multi-channel access system" of the A system will be described as a fourth embodiment with reference to FIG. In the example shown in FIG. 5, 1: n communication is performed, but in the fourth embodiment, the channel can be switched on the receiver side, and multi-channel access (MCA) is performed using a plurality of channels. . FIG. 7B shows the relationship between the local oscillation frequency of each of the transmitter and the receiver and the band of each channel. In the second and third embodiments, only the upper sideband of the transmission code "0" and the lower sideband of the transmission code "1" are transmitted and received. In this example, the transmission code "0", The case where the upper and lower sidebands of "1" are transmitted and received is shown. FIG. 7A shows a procedure for performing MCA. First, the slave station waits for a call from the master station on the calling channel. The master station receives channels 1, 2, and 3, respectively, and detects a channel having no carrier as an empty channel. When communication is performed with a predetermined slave station, data for identifying the slave station and data for specifying a vacant channel to be used for communication are transmitted on the call channel. The slave station receives this and regards it as an instruction to the own station, and transmits response data. When the master station confirms this, a communication channel is established, and communication is started on the corresponding channel.

In this example, if the frequency conversion is performed without removing any of the unnecessary sidebands of the upper sideband or the lower sideband by the filter (as in the case of the above-described embodiment, When the center frequency of the upper sideband of “0” and the lower sideband of code “1” is the local oscillation frequency of the receiver, the deviation between the local oscillation frequencies of the transmitter and the receiver causes Since a beat occurs, the local oscillation frequency on the receiver side is set to a frequency outside the lower sideband of code “0” and the upper sideband of code “1”. For example, in the case of ch1 (channel 1), the local oscillation frequency on the receiver side is 180M
Hz and 220 MHz are used. Thereby, frequency conversion is performed without generating a beat. However, if adjacent channels are arranged in the lower sideband of the code “0” and the upper sideband of the code “1”, interference occurs. Therefore, the channel frequencies are arranged so as to be separated by a bandwidth corresponding to the number of used waves (9 waves).

Next, an example of the "PWM modulation / demodulation method" of the A method will be described as a fifth embodiment with reference to FIG.

In this embodiment, the code is transmitted by changing the fundamental frequency with the transmission code, and the receiver captures the change to perform decoding. As shown in FIG. 8A, the fundamental wave oscillation circuit of the transmitter is 1 MHz when the transmission code is “1” and 2 MHz when the transmission code is “0”.
Oscillates at MHz. This fundamental wave oscillation circuit can be easily constituted by a 2 MHz oscillation circuit, a frequency dividing circuit using a D-type flip-flop, and a logic circuit. The impulse train generation circuit generates an impulse train at the cycle of the fundamental frequency.
The band-pass filter BPF transmits a component having a center frequency of 300 MHz and a pass band width of 9 MHz, that is, a plurality of frequencies near the 300th harmonic, and wirelessly transmits the same. In this example, since the pass band is 9 MHz, nine waves are transmitted when the transmission code is “0”, and four waves are transmitted when the transmission code is “1”.

As shown in FIG. 8B, on the receiver side, after the interfering wave is removed by the band-pass filter BPF, the plural frequencies are synthesized by the envelope detection circuit. The charge time constant and the discharge time constant of the envelope detection circuit are reduced to relatively increase the response of the envelope detection as compared with the code transmission speed. Thus, an impulse train waveform having a period equal to the fundamental wave frequency is detected. FIG. 9A shows an example of the detection output waveform. When the sign is “0”, an impulse train signal is obtained at a time interval of 0.5 μs, and when the sign is “1”, an impulse train signal is obtained at a time interval of 1 μs. A column signal is obtained.
The pulse interval measurement circuit measures the time interval of the impulse train signal obtained by the envelope detection, determines whether the code is “0” or “1”, and outputs the result. Thereby, it is decrypted.

However, in this method, when a strong noise is received, there is a possibility that the code is erroneously determined due to the influence.
In such a case, as shown in FIG. 8C, a time window opening / closing circuit and a determination circuit for performing a code determination based on a pulse width and a pulse level are provided. The time window opening / closing circuit passes the signal only within a predetermined time frame synchronized with the pulse of the impulse train synthesized by the envelope detection circuit. To achieve this, synchronization is established between the transmitter and the receiver before starting communication. Also, the change in pulse width due to the transmission code needs to be an integral multiple. This allows
Erroneous determination of an interference wave when the time window is closed is eliminated, and reliability is improved.

On the other hand, the sign determination circuit also utilizes the fact that the output level of the envelope detection circuit differs according to the pulse interval of the impulse train for the sign determination. That is, as described above, since the envelope detection circuit detects the charge by the charging and smoothing action of the predetermined charge time constant and discharge time constant smoothing circuit, the shorter the pulse interval of the impulse train, the higher the envelope detection output. The higher the level is, the longer the pulse interval of the impulse train is, the lower the envelope detection output level is. Therefore, as shown in FIGS. 9A and 9B, the output level of the envelope detection circuit becomes higher when the transmission code is “0” and becomes “1”.
Lower when Utilizing this relationship, as shown in FIG. 9C, the pulse interval and the pulse level are mapped on two-dimensional coordinates, and the sign is determined from the two-dimensional coordinate values.
By thus doubling the determination conditions, errors in code determination for interference waves or signal disappearance are reduced, and reliability is improved.

In the above-described example, the period of the impulse train signal is changed in two stages by 1/0 of the transmission code. However, the period of the impulse train signal may be changed in three or more stages. Assuming that this cycle change is n stages, the code output of the code determination circuit shown in FIG. 8C has n values, and transmission of a multi-level code of three or more values is possible. This method corresponds to the “multi-value coding method” of the method A shown in FIG.

Next, an example of the "spectrum count method" of the A method will be described as a sixth embodiment with reference to FIGS.

FIG. 10A is a block diagram showing the structure of the transmitter. The fundamental wave oscillating circuit intermits the fundamental wave frequency signal according to 1/0 of the transmission code. The impulse train generation circuit generates an impulse train signal at the cycle of the fundamental frequency. The band pass filter BPF has a center frequency of 300 MHz.
z, 9 MHz when the passband is 9 MHz and the transmission code is “1”.
Transmit the waves wirelessly. Thereby, the AS of the impulse train signal
Perform K modulation.

FIG. 10B is a block diagram showing the configuration of the receiver. In the receiver, the 9 waves are selectively passed through the band-pass filter BPF to remove the interfering wave, and the frequency is converted by the local oscillation signal. This results in 10 MH
The signal is converted to an intermediate frequency signal of z or less. At this time, the frequency of the local oscillation signal is cyclically swept between 295.5 MHz and 304.5 MHz, that is, continuously or at predetermined steps while maintaining the bandwidth including the nine waves. The IF (intermediate frequency) filter is a low-pass filter,
Pass a frequency band below kHz. The envelope detection circuit performs envelope detection on the signal.

As a result, as a result of the frequency conversion, nine line spectra having a difference frequency between the local oscillation frequency and the frequency of the nine waves are generated. By sequentially changing the local oscillation frequency, the nine line spectra are changed. The shift will be on the frequency axis. And one of the nine line spectra
The book enters below 250 kHz, becomes 0 Hz and returns to 25 kHz.
The operation of becoming higher than 0 kHz is performed for nine waves. FIGS. 11B and 11C show the state. When the transmission code is “1, 0”, the output signal of the envelope detection circuit changes as shown in the lower part of FIG.

As a result, a pulse waveform corresponding to the level of the intermediate frequency signal, the pass band of the IF filter, and the sweep speed of the frequency of the local oscillation signal is obtained from the envelope detection circuit. The cycle of this pulse waveform is (fundamental frequency [MHz]) ÷ sweep speed [MHz / s]. Note that the sweep speed is set to be equal to or higher than the code transmission speed.

The CPU counts the number of pulses of the output signal of the envelope detection circuit and the cyclic sweep control of the local oscillation circuit, and determines the sign from the correlation between the two. That is, if 9 pulses can be counted during one cycle of switching the frequency of the local oscillation signal, the code is regarded as “1”, and if no pulse is observed, the code is determined as “0”. However, since there is a possibility that a pulse due to noise may actually be mixed in, a threshold value is set for 1/0 determination based on the number of pulses. The determination may be made. As a result, the reliability of data transmission depends not only on the noise level but on the frequency of occurrence of the noise, and the noise resistance in an environment where suddenly strong noise is radiated is improved.

In each of the above-described embodiments of the A system, the impulse train signal itself is modulated by the transmission code. However, in each of the following embodiments, the impulse train signal is used as a local oscillation signal, and the transmission code is modulated. A plurality of frequencies are generated / combined by frequency-converting a sub-modulation wave obtained by performing narrow-band modulation on.

An example of the "pilot carrier system" of the B1 system will be described as a seventh embodiment with reference to FIGS. FIG. 12A is a block diagram showing the configuration of the transmitter. In this example, the transmission code is FSK modulated to generate a sub-modulated wave signal. The impulse train generation circuit generates an impulse train at a period of the fundamental frequency of 1 MHz output from the fundamental wave oscillation circuit, and the frequency conversion circuit converts the frequency of the sub-modulated wave with this impulse train signal.
A multi-frequency signal is generated by spreading the sub-modulation wave at equal frequency intervals. The synthesizing circuit superimposes the impulse train signal on the frequency-converted signal via the buffer amplifier circuit and wirelessly transmits the signal. The buffer amplifier circuit is used to prevent the frequency-converted signal from returning from the synthesis circuit to the impulse train signal generation circuit.

FIG. 13 shows signal spectra on the transmitter side and the receiver side. Here, f is the frequency of the fundamental frequency signal of 1 MHz.

On the receiver side, the signals of the plurality of frequencies are received by an antenna, and the impulse train signal equal to that on the transmitter side is frequency-converted as a local oscillation signal to synthesize the sub-modulated wave in frequency. Here, when the n waves are combined, the signal level increases n times, and the noise level increases Δn times since it is uncorrelated with the plurality of frequencies, so that the CN ratio increases Δn times.

However, if the frequencies of the local oscillation signals on the transmitter side and the receiver side do not completely match, a beat occurs in the demodulated waveform due to the deviation, and decoding cannot be performed normally. . Therefore, as shown in FIG. 12 (B), local oscillation signals on the receiver side are extracted and generated from signals of a plurality of frequencies transmitted from the transmitter to prevent the above-mentioned frequency shift from occurring. In FIG. 12 (B), the carrier tuning circuit captures one wave among a plurality of subcarriers superimposed on a transmission signal and tunes and oscillates. As shown in FIG. 13, in this example, oscillation is performed in synchronization with 4f. The frequency divider divides this oscillation signal by the order of the fundamental wave (in this example, 1/4)
By dividing the frequency, a square wave signal equal to the fundamental frequency f is reproduced. This is converted into a sine wave signal by a waveform shaping circuit using a filter or the like, and is applied to an impulse train generation circuit.
As a result, an impulse train signal is generated at a period of the frequency f. The frequency conversion circuit synthesizes a plurality of waves by converting the frequency of the received signal with the impulse train signal. The IF filter removes the interfering wave by selectively passing the signal component, and the FSK demodulation circuit decodes the signal by performing demodulation in accordance with the FSK modulation on the transmitter side.

If the tuning oscillation frequency of the carrier wave tuning circuit is fixed, the carrier wave cannot be reproduced when the frequency is disturbed.
It is configured so that it can be tuned to an arbitrary frequency. At the same time, the frequency division number of the frequency divider can be changed according to the order of the tuning frequency. The CPU monitors the demodulated output, and changes the tuning frequency and the frequency division number when it is determined that the communication quality has deteriorated.

The modulation and demodulation of the transmission code is not limited to FSK, but may be ASK or PSK. With such a configuration, frequency synthesis can be performed without generating a beat.

Next, an example of the "pulse width 0 beat control system" of the B2 system will be described as an eighth embodiment with reference to FIG. In the transmitter shown in (A), the fundamental wave oscillation circuit generates a signal of the fundamental wave frequency f1, and the impulse train generation circuit generates an impulse train signal at the cycle of f1.
The narrow band modulation circuit modulates a transmission code by a predetermined modulation method such as ASK, FSK, PSK or the like, and generates a sub-modulated wave signal. The frequency conversion circuit converts the frequency of the sub-modulated wave signal with an impulse train signal and transmits the signal by radio. In the receiver shown in (B), the voltage-controlled oscillation circuit oscillates a fundamental frequency signal having the frequency f2, and the impulse train generation circuit repeatedly generates an impulse signal at that cycle. The frequency conversion circuit converts the frequency of the received signal from the antenna into an intermediate frequency signal using an impulse train signal, and synthesizes the plurality of frequencies. The IF filter removes an interference wave by passing only a band including a component of a transmission code. The narrow-band demodulation circuit demodulates by a method corresponding to the modulation method on the transmitter side and outputs a code.

When the fundamental wave frequency f1 on the transmitter side is not equal to the fundamental wave frequency f2 on the receiver side, a beat corresponding to the frequency difference between f1 and f2 occurs when a plurality of frequencies are synthesized by the frequency conversion circuit. Therefore, a beat cycle voltage conversion circuit shown in the figure is provided. The envelope detection circuit performs an envelope detection of the intermediate frequency signal and shapes the waveform to generate a rectangular wave signal having a beat component frequency. In addition,
Since the beat component is also included in the narrow-band demodulated signal, the narrow-band demodulated signal may be configured to be subjected to envelope detection. The XOR circuit generates an exclusive OR signal of a signal whose waveform has been shaped and a signal obtained by delaying the signal by a predetermined time by a delay circuit. As a result, a rectangular wave signal whose level changes at the rising portion and the falling portion of the rectangular wave signal corresponding to the beat cycle is obtained. FIG. 14C is a waveform diagram of that portion. The loop filter smoothes the output signal of the XOR circuit with a predetermined time constant for making the response of the feedback control appropriate, and outputs the smoothed signal as a control voltage to the voltage controlled oscillation circuit.

As the frequency of the beat increases, the XOR
Since the cycle of the pulse output from the circuit is shortened, the beat can be canceled by controlling the oscillation frequency of the voltage controlled oscillation circuit according to the pulse cycle. However,
Since only the absolute value of the frequency difference between f1 and f2 can be determined only by the beat cycle voltage conversion circuit, control is performed by the following method.

FIG. 15B is a flowchart showing the processing procedure of the CPU. Here, the larger the error between the fundamental wave frequency f2 on the receiver side and the fundamental wave frequency f1 on the transmitter side, the higher the output voltage of the beat period voltage conversion circuit is. It is assumed that the oscillation frequency increases as the value increases. First, a voltage controlled oscillator (hereinafter referred to as VCO)
Is a predetermined voltage (Δ
V). As a result, if the output voltage of the beat period voltage conversion circuit decreases, that is, when the fundamental frequency of the receiver is higher than the fundamental frequency of the transmitter, the control voltage for the VCO is increased by ΔV from the current voltage. Lower. By repeating this, the fundamental wave frequency f2 on the receiver side is reduced and the fundamental wave frequency f2 on the transmitter side is reduced.
Move closer to 1. If the output voltage of the beat period voltage converter increases when the control voltage for the VCO is reduced by ΔV, that is, when the fundamental frequency f2 on the receiver side is lower than the fundamental frequency f1 on the transmitter side , V
The control voltage for CO is increased by ΔV from the current voltage. By repeating this, f2 is raised and f
Move closer to 1. FIGS. 15B and 15C show such a state.

As shown by the curve in FIG. 15C, ΔV is adjusted so that the change in the oscillation frequency with respect to the control voltage of the VCO becomes small when the beat frequency is near zero. This prevents hunting due to excessive feedback.

In addition to the above method, f2 is set to a frequency higher than f1 in advance in consideration of the accuracy of the parts, and the beat frequency is reduced to approximately 0 by decreasing f2. f2 may be maintained. Conversely, f2 may be set to a frequency lower than f1 in advance, and the beat frequency may be set to approximately 0 by increasing f2, and then f2 may be maintained.

Next, an example of the "multiplication division / frequency division multiplication system" of the C1 system will be described as a ninth embodiment with reference to FIG. (A) is a block diagram showing a configuration of a transmitter,
The narrow band modulation circuit obtains a sub-modulated wave by modulating in a form in which a carrier is always transmitted, such as FSK or PSK. The local oscillation circuit outputs a local oscillation signal having a single frequency fo, and the frequency conversion circuit converts the frequency of the sub-modulated wave using the local oscillation signal. As a result, two waves of the upper sideband fa and the lower sideband fb are spread around fo.

FIG. 16B is a block diagram showing the structure of the receiver. The two tuned oscillation circuits each have a frequency f.
a and fb are extracted by a filter and oscillate at those frequencies. The multiplication circuit is a mixer circuit that multiplies the signals of fa and fb, and outputs a frequency signal of fa + fb.
The frequency divider divides the frequency by １ ／, and the fundamental frequency is (fa)
+ Fb) / 2 is obtained. The waveform shaping circuit shapes the waveform to generate a sine wave signal of the same frequency, and the frequency conversion circuit frequency-converts the waveform-shaped signal of the received signal from the antenna as a local oscillation signal. The IF filter removes an interfering wave by passing only the sub-modulated wave synthesized by the frequency conversion. The narrow-band demodulation circuit demodulates the code by a method corresponding to the narrow-band modulation on the transmitter side.

In the example shown in FIG.
Although the frequency division is performed after multiplying the waves fa and fb, the frequency division may be performed first as shown in FIG. 16C, and the signals may be multiplied.

As described above, by performing frequency synthesis using the midpoint of the upper and lower sidebands by the frequency conversion of the narrow-band modulated sub-modulated wave as the local oscillation frequency on the receiver side, the oscillation frequency on the transmitter side can be changed. Frequency conversion with equal signals,
Demodulation can be performed without generating a beat.

Next, an example of the "multi-channel access system" of the C1 system will be described as a tenth embodiment with reference to FIG. In the transmitter shown in FIG. 17A, the frequency is shifted by further performing frequency conversion by the second frequency conversion circuit on the signal spread into two waves fa and fb by the first frequency conversion circuit. The second local oscillation circuit oscillates at a frequency according to the channel selection. As a result, two waves of fa and fb are wirelessly transmitted at a frequency corresponding to the channel. FIG. 18 shows an example of a frequency shift corresponding to each channel.

In the receiver shown in FIG. 17B, the second frequency conversion circuit frequency-converts the signal received from the antenna according to the selection of the channel, and converts the frequency of the selected channel to 2.
The signal including the wave signals fa and fb is converted into a certain frequency band. Subsequent processing is the same as that shown in FIG. In this manner, one-to-n communication can be performed using a plurality of channels. Further, multi-channel access using a plurality of channels becomes possible.

Next, an example of the "pilot local oscillation system" of the C2 system will be described with reference to FIGS.
This will be described with reference to FIG.

In this example, the local oscillation frequency signal used at the time of transmission is transmitted at a frequency separated from the sub-modulated wave, thereby facilitating the extraction and reproduction of the local oscillation frequency signal on the receiver side.

In the transmitter shown in (A), the transmission code is FS
K modulation is performed to obtain a sub-modulated wave. Here, it was FSK,
In addition, ASK and PSK are also possible. The local oscillation circuit oscillates at 150 MHz (fL), the doubling circuit converts this to a 300 MHz signal, and the frequency conversion circuit mixes the sub-modulation wave with the 300 MHz signal to convert the frequency. The synthesizing circuit superimposes the 150 MHz signal fL as a pilot signal via the buffer amplifier circuit and transmits the radio signal by radio.

In the receiver shown in (B), a 150 MHz pilot signal is extracted by a band-pass filter BPF.
The tuning oscillation circuit performs tuning oscillation at the frequency. The doubling circuit doubles this to generate a signal of 300 MHz. The frequency conversion circuit performs frequency conversion by mixing a 300 MHz signal with the received signal. The IF filter passes the component of the sub-modulation wave. The narrow-band demodulation circuit demodulates this and outputs a code.

By transmitting the local oscillation frequency used at the time of transmission in such a manner as to be separated from the sub-modulated wave in frequency,
The pilot signal can be easily extracted, and the local oscillation frequency signal can be easily reproduced on the receiver side.

Next, an example of the “N-wave compatible system” of the C2 system will be described as a twelfth embodiment with reference to FIGS. 21 and 22.

In this example, after multiplying the basic local oscillation signal for each of the transmission and reception, an impulse train is further generated (2n).
A plurality of waves are generated and synthesized by performing frequency conversion with the second harmonic. As is clear from comparison with FIG. 19, in this example, in the transmitter and the receiver, an impulse train generation circuit is provided between the doubler circuit and the frequency conversion circuit.

FIG. 22 shows a spectrum of a signal on the transmitter side and a spectrum of the signal on the receiver side. As is apparent from comparison with FIG. 20, the sub-modulated wave is spread to a plurality of frequencies and transmitted. Are combined to reproduce the sub-modulated wave.

Next, an example of the "high-speed beat method" of the A method will be described as a thirteenth embodiment with reference to FIGS.

In the transmitter shown in FIG. 23A, the fundamental wave oscillation circuit intermittently oscillates at 1 MHz according to the transmission code.
The impulse train generation circuit generates an impulse train signal based on the impulse train signal, and the band-pass filter BPF wirelessly transmits nine waves with a bandwidth of 9 MHz around 300 MHz. FIG.
(A) shows the frequency spectrum of the transmission signal according to the transmission code. In the receiver shown in FIG.
The band-pass filter BPF passes the signal component of the above-mentioned band, and the fundamental wave oscillation circuit operates at a fundamental wave frequency of 1 MHz on the transmitter side.
Oscillates at a frequency higher by 100 Hz, and an impulse train generation circuit generates an impulse train signal of that cycle.
The band-pass filter BPF passes the signal component in the above band, and the frequency conversion circuit converts the frequency of the signal with an impulse train signal. As a result, 9 waves in the 300 MHz band become 2
It is rearranged from 9.6 kHz to 30.4 kHz at 100 Hz intervals. This is center frequency 30kHz, bandwidth 900
Unwanted waves are removed through an IF filter of Hz. The envelope detection circuit performs envelope detection on this. This allows
Since each of the plurality of frequency components is rectified and combined by smoothing, the SN ratio of the demodulated signal is improved. Since the phase condition of each frequency component is equal, no beat occurs in the composite waveform. By the way, if these frequency groups are detected by a normal demodulation circuit without performing envelope detection, beats are generated at a period equal to a frequency shift of 100 Hz.

Generally, the difference between the fundamental frequency of transmission and reception is Δ
Assuming that the nth harmonic is used, the rearranged frequency of the receiver after frequency conversion is nΔ. In the above example, Δ = 10
0 Hz and n = 300, for example, Δ = 10 kHz
Assuming that z and n = 300, the nine waves in the 300 MHz band are rearranged from 2.96 MHz to 3.04 MHz at intervals of 10 kHz. Therefore, the signal component may be extracted through an IF filter having a center frequency of 3 MHz and a bandwidth of 90 kHz.

Note that the transmission speed of the transmission code is B [bit /
s], by setting (nΔ) >> B, the output signal of the envelope detection can be demodulated as a normal code.

Next, an example of the "simple Fourier local oscillation reproduction system" of the B1 system will be described as a fourteenth embodiment with reference to FIGS.

In the transmitter shown in FIG.
A modulation circuit performs FSK modulation on a transmission code, a fundamental wave oscillation circuit generates a fundamental wave of 1 MHz, an impulse train generation circuit generates an impulse in the cycle, and a frequency conversion circuit performs FS modulation.
By frequency-converting the K-modulated sub-modulated wave with an inrush train signal, a plurality of waves are wirelessly transmitted as shown in FIG.

In the receiver shown in FIG. 25B, envelope detection is performed on the signals of the plurality of frequencies by an envelope detection circuit. As a result, the signal of each frequency component is rectified and smoothed, and the waveform is synthesized. By appropriately setting the time constant of this smoothing circuit, a pulse having a period equal to the fundamental frequency on the transmitter side is detected. The pulse is shaped by a waveform shaping circuit and passed through an impulse train generating circuit, whereby a signal having a local oscillation frequency equal to that of the transmitter is reproduced as shown in FIG. The frequency conversion circuit on the receiver side synthesizes a plurality of waves by frequency-converting the received signal with the impulse train signal, the IF filter passes only the frequency component, and the FSK demodulation circuit demodulates the code. Next, an example of the "subcarrier PLL system" of the B3 system will be described as a fifteenth embodiment with reference to FIGS.

In the transmitter shown in FIG. 27, the reference oscillation circuit generates a reference frequency signal, and the divide-by-4 circuit divides the reference frequency signal to a quarter frequency. The AM modulation circuit AM-modulates a transmission code by a signal obtained by dividing the reference frequency signal by four to generate a sub-modulated signal. The impulse train signal generation circuit generates an impulse at the cycle of the reference frequency signal, and the band-pass filter BPF passes the impulse train signal of a predetermined frequency band. The balanced modulation circuit converts the frequency of the sub-modulated signal with the impulse train signal of the predetermined frequency band, and transmits the signal by radio. FIG. 29A shows this state. In this way, a plurality of modulated signals having (2i + 1) spectrum arrangements at the frequency interval ωc / 2 are obtained. Here, since the subcarrier and the impulse train signal are generated based on the common reference frequency signal, they are in-phase signals.

In the receiver shown in FIG. 28, the VCO oscillation circuit generates a reference frequency signal, and the impulse train signal generation circuit generates an impulse at the cycle of the reference frequency signal.
The band-pass filter BPF passes an impulse train signal in a predetermined frequency band. The balanced integrator is a so-called double balance mixer, and converts the frequency of a received signal with an impulse train signal in the above-mentioned predetermined frequency band. The IF filter passes the sub-modulation frequency component ωc / 4 as the center frequency. When the oscillation frequency of the VCO oscillation circuit deviates from the reference frequency on the transmitter side, the output signal of the IF filter includes a beat resulting from the frequency deviation. On the other hand, the divide-by-4 circuit divides the reference frequency signal to a quarter frequency. The phase comparison circuit obtains a phase difference between the frequency-divided signal and the output signal of the IF filter, and outputs a signal corresponding to the difference (the level increases as the phase difference increases). The low-pass filter LPF extracts the low-frequency component and uses it as a control signal for the VCO oscillation circuit. A PLL circuit is constituted by the VCO oscillation circuit, the divide-by-4 circuit, the phase comparison circuit, and the LPF. As a result, the oscillation frequency of the VCO oscillation circuit follows the reference frequency on the transmitter side. The AM demodulation circuit detects the sub-modulation signal that does not include the beat, and outputs this as a code. FIG. 29B shows this state. In this way, the amplitude of the demodulated signal increases by the same number as the number (2i + 1) of the used line spectra, so that noise resistance is improved and long-distance transmission is possible.

In the above example, in the transmitter and the receiver, the reference frequency signal is divided by 4 to generate a subcarrier frequency signal, and the carrier frequency (the fundamental frequency of the impulse train signal) and the subcarrier Is a multiple of 1: 4, but an impulse train signal may be generated using a reference frequency signal as a subcarrier frequency and a signal obtained by multiplying the frequency by four as a fundamental wave. The multiple relationship is not limited to 1: 4, but may be an integer ratio relationship. In this manner, frequency synthesis is performed without generating a beat.

Finally, the configuration of the radio communication system according to the sixteenth embodiment will be described with reference to FIG. In the first to third embodiments, an example has been described in which a frequency band is divided into a plurality of parts and codes are transmitted. However, in the fifteenth embodiment,
The code is transmitted depending on which band the signal component exists in. However, the band is shifted for each modulation of the transmission code. FIG.
In the example shown in FIG. 0, if the transmission code is “0” using four frequency bands indicated by A, B, C, and D, the clock transits clockwise to the next band, and the transmission code becomes “1”. If the transmission code is “2”, the transition is made to the next three bands.

On the transmitter side, for example, assuming that the transition source band is A, if the transmission code is “0”, the band is transitioned to B, that is, a signal appears in band B, and the transmission code is “1”. If the transmission code is “2”, the transition to the band D is made. Thus, the transmission band is shifted according to the transmission code. On the receiver side, for example, after receiving band A, code "0" if a signal is present in band B, code "1" if a signal is present in band C, and band D
If there is a signal in, the signal is decoded as code “2”. After receiving a signal in a certain band in this manner, the code is determined according to the transition of the band to which band the signal is next.

Although the four bands are arranged in a ring in FIG. 30, these four bands are arranged linearly on the frequency axis.

When the band is divided into n bands as described above, by shifting the band for each modulation, a code of (n-1) value per modulation can be transmitted in a state where noise is not disturbed, and the number of codes can be increased. The amount of transmission per time can be improved by the conversion into a value. Further, when a certain band is constantly disturbed, by reducing the number of multi-values, transmission can be performed while avoiding the disturbed band. Thereby, the anti-jamming performance can be improved.

[0087]

According to the radio communication system of the first aspect, since code transmission is performed by dividing the frequency band, the probability of being affected by an interference wave is reduced, and the anti-jamming performance is improved.

According to the wireless communication system of the second aspect, in addition to the above effects, low-frequency processing can be performed, so that the receiving sensitivity can be improved and the stability of the receiving circuit can be improved. In addition, since the code is reproduced based on the envelope detection output of the predetermined band, that is, information is given to the frequency interval and phase of a plurality of waves, so that the transmitter and the receiver side perform local conversion for frequency conversion. Even if there is some error in the oscillation frequency, normal communication can be performed.

According to the wireless communication system of the third aspect, one-to-n communication can be easily realized even when a weak radio wave is used.

According to the wireless communication system of the fourth aspect, the amount of transmission per time due to multi-level coding is improved.

According to the wireless communication system of the fifth aspect, the reliability of communication can be improved by selecting a band with a small influence in the MCA method. Also,
By giving a unique code to the group of the master station and the slave station, a plurality of groups can be arranged in the same area.

According to the radio communication system of the sixth aspect, at the time of demodulation, demodulation is performed according to the presence or absence of a pulse signal at a predetermined time interval. It can be hard to receive.

[0093] According to the wireless communication system of the seventh aspect, since the amount of information per modulation increases, the transmission speed can be improved.

According to the wireless communication system of the eighth aspect, even if a single strong interfering wave arrives, its influence is:
By counting the number of pulsed spectrums in a predetermined band at the receiver side, code demodulation is performed according to the number. If the maximum number of pulsed spectrums is n, the effect becomes 1 / n, and the SN ratio becomes Degradation is minimized.

According to the wireless communication system of the ninth aspect, of the impulse train signal superimposed on the transmitter side, one wave in the best state is extracted and frequency-divided by the order of the spectrum. Since a signal having a fundamental frequency equal to the following is obtained, frequency synthesis without generation of a beat is performed, and the CN ratio is improved.

According to the radio communication system of the tenth aspect, even if there is an error in the period of the impulse train signal between the transmitter and the receiver, a beat caused by the error is not generated on the receiver. Since the period of the impulse train signal on the receiver side is controlled, it is possible to combine a plurality of waves without being affected by the beat.

According to the radio communication system of the eleventh aspect, since the frequency of the local oscillation signal on the transmitter side can be reproduced on the receiver side, even if a frequency fluctuation occurs on the transmitter side, communication can be performed without being affected by the fluctuation. Can be performed.

According to the wireless communication system of the twelfth aspect, communication according to the channel becomes possible, and multi-channel access becomes possible.

According to the wireless communication system of the thirteenth aspect, the local oscillation signal and the sub-modulation wave are separated in frequency and combined, and the local oscillation signal is extracted and reproduced on the receiver side. Does not occur, the circuit configuration is simplified, and design and adjustment are facilitated.

According to the radio communication system of the fourteenth aspect, in addition to the above-described effects, dispersion / combination of a plurality of frequencies can be performed without generating a beat, so that anti-jamming performance is improved.

According to the fifteenth aspect of the present invention, at the intermediate frequency stage after the frequency conversion, a frequency interval equal to the frequency deviation is generated due to the deviation of the fundamental frequency between the transmitter and the receiver. Since the plurality of waves are rearranged, unnecessary waves are easily disturbed by the narrow band filter. Also,
Since the plurality of waves are decoded by envelope detection, interference resistance is also improved.

According to the wireless communication system of the sixteenth aspect, the receiver reproduces an impulse train signal having a cycle equal to the fundamental frequency of the transmitter, so that a plurality of waves are generated without generating a beat during frequency conversion. Can be synthesized, and synthesis of a plurality of frequencies having high resistance to interference can be performed.

According to the wireless communication system of the seventeenth aspect, by generating the subcarrier and carrier frequencies on the basis of a common reference frequency signal on the transmitter side, the phases of the two signals match, and the receiver side Since the fundamental frequency of the impulse train signal is controlled by the PLL based on the frequency of the subcarrier extracted in the above, it is possible to combine a plurality of waves without generating a beat.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a wireless communication system according to a first embodiment.

FIG. 2 is a waveform diagram of each part in the system.

FIG. 3 is a block diagram illustrating a configuration of a wireless communication system according to a second embodiment;

FIG. 4 is a diagram showing an example of frequency conversion in the system.

FIG. 5 is a block diagram showing a configuration of a wireless communication system according to a third embodiment.

FIG. 6 is a diagram illustrating a relationship between a channel and a frequency band.

FIG. 7 is a diagram showing a configuration of a wireless communication system according to a fourth embodiment.

FIG. 8 is a block diagram showing a configuration of a wireless communication system according to a fifth embodiment.

FIG. 9 is a diagram showing a waveform diagram and a sign determination condition in the system.

FIG. 10 is a block diagram showing a configuration of a wireless communication system according to a sixth embodiment.

FIG. 11 is a diagram showing an example of a frequency spectrum and a time waveform in the system.

FIG. 12 is a block diagram showing a configuration of a wireless communication system according to a seventh embodiment.

FIG. 13 is a diagram showing an example of a spectrum on a transmitter side and a spectrum on a receiver side in the same system.

FIG. 14 is a block diagram and a waveform diagram showing a configuration of a wireless communication system according to an eighth embodiment.

FIG. 15 is a diagram showing a control procedure of the voltage controlled oscillation circuit.

FIG. 16 is a block diagram showing a configuration of a wireless communication system according to a ninth embodiment.

FIG. 17 is a block diagram showing a configuration of a wireless communication system according to a tenth embodiment.

FIG. 18 is a diagram showing an example of frequency conversion for each channel in the system.

FIG. 19 is a block diagram illustrating a configuration of a wireless communication system according to an eleventh embodiment.

FIG. 20 is a diagram showing an example of a spectrum on a transmitter side and a spectrum on a receiver side in the same system.

FIG. 21 is a block diagram illustrating a configuration of a wireless communication system according to a twelfth embodiment.

FIG. 22 is a diagram showing an example of a spectrum on a transmitter side and a spectrum on a receiver side in the same system.

FIG. 23 is a block diagram showing a configuration of a wireless communication system according to a thirteenth embodiment.

FIG. 24 is a diagram showing an example of a frequency spectrum on a transmitter side and a receiver side in the same system.

FIG. 25 is a block diagram illustrating a configuration of a wireless communication system according to a fourteenth embodiment.

FIG. 26 is a diagram showing an example of a frequency spectrum on a transmitter side and a receiver side in the same system.

FIG. 27 is a block diagram illustrating a configuration of a wireless transmitter in a wireless communication system according to a fifteenth embodiment.

FIG. 28 is a block diagram showing a configuration of a wireless receiver of a wireless communication system according to a fifteenth embodiment.

FIG. 29 is a diagram showing an example of a frequency spectrum on a transmitter side and a receiver side in the same system.

FIG. 30 is a diagram showing an example of band transition for each modulation according to the sixteenth embodiment.

FIG. 31 is a diagram showing a relation of each wireless communication system of the present invention in a tree format.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mikio Oda F-term in Omron Co., Ltd. 5K022 AA12 AA22 (10) Hanazono Todocho, Ukyo-ku, Kyoto-shi, Kyoto

Claims (19)

[Claims] 1. A radio transmitting apparatus comprising: means for generating an impulse train signal that repeats at a predetermined cycle; and band control means for controlling a transmission frequency band of the impulse train signal in accordance with a transmission code; Band selecting means for extracting a plurality of frequency signals of a predetermined frequency band transmitted from the apparatus, means for performing envelope detection of the plurality of frequency signals for each of the predetermined frequency bands, and a level difference between envelope detection signals of the respective frequency bands. A radio receiving apparatus comprising: a code reproducing unit that reproduces the transmission code. 2. The band control unit frequency-converts a signal of a predetermined band of the impulse train signal, and the band selection unit band-limits a received signal,
2. The wireless communication system according to claim 1, wherein frequency conversion is performed on a lower frequency side according to a frequency band to be selected. 3. The band control unit controls the transmission frequency band within a predetermined frequency channel among a plurality of frequency channels, and the band selection unit controls the transmission frequency band within a predetermined frequency channel among the plurality of frequency channels. The wireless communication system according to claim 1, wherein a plurality of frequency signals are extracted. 4. The band control means changes a transmission frequency band of the impulse train signal according to a transmission code, and the code reproducing means changes the transmission frequency band by a level difference of the envelope detection signal. The wireless communication system according to claim 1, wherein the wireless communication system detects and reproduces the transmission code. 5. A means for performing multi-channel access control using a predetermined frequency channel among the plurality of frequency channels for control and allocating another frequency channel for communication using the control frequency channel. The wireless communication system according to claim 3. 6. A means for generating a fundamental frequency signal having a different frequency in accordance with a transmission code, and generating an impulse train signal having a repetition period corresponding to the frequency of the fundamental wave signal based on the fundamental frequency signal, for wireless transmission. And a means for performing envelope detection on the wirelessly transmitted signal to demodulate a pulse signal, and a means for reproducing the transmission code from a time interval of the pulse signal. A wireless communication system comprising: a wireless receiving device; 7. The transmission code having three or more values.
A wireless communication system according to claim 1. 8. A radio transmitting apparatus comprising: means for intermittently transmitting an impulse train signal repeated in a predetermined cycle in accordance with a transmission code, and wirelessly transmitting the impulse train signal; and cyclically sweeping a predetermined frequency band of the wirelessly transmitted signal in a narrow band. A wireless communication system comprising: means for receiving and performing envelope detection; and means for detecting a transmission code from a temporal change in a detection signal level by envelope detection. 9. A means for modulating a transmission code to generate a sub-modulation wave signal, a means for frequency-converting the sub-modulation wave signal by an impulse train signal repeated at a predetermined period, and A radio transmitting apparatus comprising: a signal superimposing means for radio communication; and an impulse train synchronized with the impulse train signal synchronized with one of a plurality of frequency signals based on the impulse train signal among the wirelessly transmitted signals. Means for generating a signal;
A wireless communication system comprising: a means for frequency-converting the signal wirelessly transmitted by the generated impulse train signal; and a means for demodulating the signal frequency-converted by the means. 10. A radio transmitting apparatus comprising: means for modulating a transmission code to generate a sub-modulated wave signal; and means for radio-transmitting the sub-modulated wave signal by performing frequency conversion with an impulse train signal repeated at a predetermined cycle. Means for frequency-converting the radio-transmitted signal with an impulse train signal repeated at a predetermined cycle; means for envelope-detecting the signal frequency-converted by the means; and beats included in the signal detected by the means. Means for controlling the cycle of the impulse train signal in a direction to cancel the beat in accordance with the cycle of the component, and a radio receiving apparatus including means for demodulating the frequency-converted signal and reproducing the transmission code, Wireless communication system. 11. A means for modulating a transmission code to generate a sub-modulation wave signal, and dispersing said sub-modulation wave signal into an upper sideband and a lower sideband centering on the frequency of a local oscillation signal, and performing wireless transmission. A radio transmitting apparatus comprising: a frequency converting unit that performs the above operation; a tuning oscillating unit that oscillates in synchronization with a carrier component of each of the upper sideband and the lower sideband of the wirelessly transmitted signal; The frequency signal of the sum of the oscillation signals is 1
A wireless communication system comprising: means for generating a local oscillation signal by dividing the frequency by ／; and means for frequency-converting the signal wirelessly transmitted by the local oscillation signal. 12. A means for frequency-shifting upper and lower sideband signals based on the frequency conversion frequency in accordance with a channel is provided in the wireless transmission device, and the upper and lower sidebands of the wirelessly transmitted signal are provided. The wireless communication system according to claim 11, wherein a means for shifting a sideband to a predetermined frequency band according to a channel is provided in the wireless receiving device. 13. A means for modulating a transmission code to generate a sub-modulation wave signal, a means for generating a local oscillation signal, and a means for frequency-converting the sub-modulation wave signal with a signal obtained by multiplying the local oscillation signal. Means for wirelessly transmitting the local oscillation signal as a pilot signal to the signal whose frequency has been converted by the means, and a signal tuned to the pilot signal from the wirelessly transmitted signal to oscillate and multiply. Multiplying means for generating a local oscillation signal of the same multiple as the local oscillation signal on the side of the wireless transmission device, means for frequency-converting the signal transmitted wirelessly by the local oscillation signal, and a signal frequency-converted by the means. And a wireless receiving device having means for demodulating the signal. 14. The frequency converting means of the radio transmitting apparatus frequency-converts the sub-modulated wave signal with an impulse train signal having the multiplied signal as a repetition cycle, and the frequency converting means of the receiving apparatus comprises: 14. The radio communication system according to claim 13, wherein said radio-transmitted signal is frequency-converted by an impulse train signal having a repetition period of the signal multiplied by said multiplication means. 15. A radio transmission apparatus comprising means for intermittently or amplitude-modulating an impulse train signal repeated at a predetermined cycle in accordance with a transmission code, wherein the radio transmission apparatus is shifted by a predetermined frequency from a repetition frequency of the impulse train signal on the radio transmission apparatus side. A radio receiving means for frequency-converting the radio-transmitted signal with an impulse train signal having a repetition frequency, and means for performing envelope detection only for a band including the transmission code information of the signal frequency-converted by the means; A wireless communication system comprising: a device. 16. A means for modulating a transmission code by a modulation method in which a carrier wave is always output to generate a sub-modulation wave signal, and frequency-converting the sub-modulation wave signal with an impulse train signal repeated at a predetermined cycle, for wireless transmission. And a means for performing envelope detection on the wirelessly transmitted signal to reproduce an impulse train signal that repeats at a period equal to the impulse train signal on the wireless transmitting apparatus side. And a means for frequency-converting the wirelessly transmitted signal by the obtained impulse train signal. 17. A means for generating two frequency signals having an integer ratio of a reference frequency, a means for modulating a transmission code at a lower frequency of the two signals to generate a sub-modulated signal, A radio transmission apparatus comprising: a means for generating an impulse train signal that repeats at a higher frequency of the two frequency signals, and a means for frequency-converting the sub-modulation signal using the impulse train signal and performing radio transmission; Means for generating two frequency signals having a relationship of an integer ratio of: a means for frequency-converting the wirelessly transmitted signal by an impulse train signal repeated at a higher frequency of the two frequency signals; Means for extracting a frequency component of the sub-modulation signal from the signal frequency-converted by the first and second sub-modulation signals; Wireless communication system consists of a radio receiver, comprising with, and means for controlling said reference frequency in the direction in which the difference is reduced performs phase comparison between the frequency components of the item. 18. The wireless transmission device according to claim 1, wherein: 19. The wireless receiving device according to claim 1, wherein: