JPH09191270A - Transmitter-receiver employing spread spectrum, communication system, transmission reception method and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the configuration of a correlation device. SOLUTION: A transmitter-receiver 1 applies spread spectrum to a signal wave by a pseudo noise code series and sends the resulting signal, the transmitter-receiver 1 receives again the signal wave and a correlation device 21 of the transmitter-receiver 1 applies inverse spread spectrum processing to the signal. In this case, the transmitter-receiver 1 divides the signal in the unit of one tip of the pseudo noise code series and sends the result, the correlation 21 multiplies the signal wave received after the lapse of a prescribed time with one tip of the pseudo noise code series and integrates the result of multiplication over one or two periods or over of the pseudo noise code series.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to spread spectrum,
Transmitting the signal wave spread from the transmitter / receiver, receiving the signal wave again at the transmitter / receiver, and despreading at the transmitter / receiver, the transmitter / receiver or transmission method using spread spectrum, or the signal wave spread from the interrogator The present invention relates to a communication system or a communication method using spread spectrum, in which a transmitted signal wave is received by a responder, returned to an interrogator, and despread by the interrogator.

[0002]

2. Description of the Related Art As a conventional communication system using this kind of spread spectrum, for example, Japanese Patent Laid-Open No. 6-18885.
No. 7 and JP-A-5-297131. In these systems, the interrogator spreads the interrogation wave with a pseudo-noise code sequence and transmits the interrogation wave from the interrogator antenna. The transmitted interrogation wave is received by the transponder and is data-modulated or is not data-modulated, and is sent back from the transponder to the interrogator again, and the interrogator performs correlation calculation with the pseudo-noise code sequence, So-called despreading is performed, and noise resistance is improved by performing spectrum spreading in this way.

This pseudo-noise code sequence uses a code sequence of 1 and -1 (or 0 and 1) that has a small cross-correlation, a sharp auto-correlation property, and a random long period. Further, Japanese Patent Laid-Open No. 4-242188 discloses a system in which a transponder is provided with a delay line that delays at least a time required for the interrogator to transmit a spread spectrum signal wave to the transponder. ing.

[0004]

However, in the conventional system, when despreading the response signal returned from the transponder by the interrogator, the correlation calculation must be performed collectively for each period of the pseudo noise code sequence. However, there is a problem that the configuration of the correlator becomes complicated. In addition, when increasing the code length of the pseudo noise code sequence, it may be necessary to replace the correlator, and it is difficult to use the pseudo noise code sequence having a long code length. .

Further, when the transponder is provided with a delay line as in Japanese Patent Laid-Open No. 4-242188, it is possible to ensure the separation of the transmission signal and the response signal in the interrogator, but the signal is attenuated by the delay line. There is also a problem that it becomes large and as a result the S / N ratio deteriorates. The present invention has been made in view of the above problems, and an object of the present invention is to provide a transceiver using spread spectrum, a communication system, a transmission method, and a communication method that can simplify the configuration of a correlator.

Another object of the present invention is to provide a communication system and a communication method which do not cause the problem of signal attenuation due to the delay line even if the transponder is provided with the delay line.

[0007]

In order to achieve the above object, the invention according to claim 1 transmits a signal wave in a transmitter / receiver by performing spectrum spreading with a pseudo noise code sequence,
In a transceiver using spread spectrum, in which the signal wave is received again by the transceiver and despread by the correlator of the transceiver, the transceiver divides the signal wave into sub-chip units of the pseudo noise code sequence. In addition, the correlator multiplies the signal wave received after a lapse of a predetermined time from the transmission by the partial chip of the pseudo noise code sequence, and integrates the multiplication result over one period or two periods or more of the pseudo noise code sequence. It is characterized by doing.

According to the second aspect of the present invention, the interrogator transmits the signal wave by spectrum spreading with a pseudo-noise code sequence, the signal wave is received by the transponder, and then sent back to the interrogator. In a communication system using spread spectrum, which despreads the signal wave sent back by the correlator, an interrogator divides the signal wave into sub-chip units of the pseudo noise code sequence and transmits the signal wave, and the correlator Is characterized in that a signal wave received after a lapse of a predetermined time from transmission is multiplied by a partial chip of the pseudo noise code sequence, and the multiplication result is integrated over one period or two periods or more of the pseudo noise code sequence.

According to the third aspect of the invention, the interrogator correlates the interrogator by transmitting the signal wave by spectrum spreading using a pseudo-noise code sequence, receiving the signal wave by the transponder, and then returning the interrogator to the interrogator. In a communication system using spread spectrum, which despreads the signal wave sent back by
The interrogator is a part that transmits by dividing each bit of the Manchester-encoded signal wave into sub-chip units of the pseudo noise code sequence and a part that transmits without dividing into sub chip units of the pseudo noise code sequence. And a signal wave received after a predetermined time has elapsed from the transmission, and the partial chip of the pseudo noise code sequence is multiplied, and the multiplication result is 1 cycle or 2 cycles or more of the pseudo noise code series. It is characterized by integrating over.

The invention according to claim 4 is the invention according to claim 2 or 3.
In the communication system using spread spectrum described above, the responder sends the signal wave from the interrogator back to the interrogator through a delay line. According to a fifth aspect of the present invention, in the communication system using spread spectrum according to the second, third or fourth aspect, the responder detects a signal wave from the interrogator and an output from the wave detector. A control circuit that identifies and outputs a data modulation signal, and a data modulation circuit that performs data modulation on the signal wave from the interrogator based on the data modulation signal of the control circuit are provided.

According to a sixth aspect of the present invention, the transmitter / receiver performs signal spectrum spreading with a pseudo-noise code sequence, transmits the signal wave, the transmitter / receiver receives the signal wave again, and the transmitter / receiver despreads the spectrum. In the transmission method using, the transmitter / receiver divides the signal wave in units of partial chips of the pseudo noise code sequence and transmits the signal wave, and a signal wave received after a predetermined time has elapsed from the transmission and the partial chip of the pseudo noise code sequence. Is multiplied, and the multiplication result is integrated over one period or two or more periods of the pseudo noise code sequence.

According to the invention of claim 7, the interrogator transmits the signal wave by performing spread spectrum with a pseudo-noise code sequence, and after receiving the signal wave by the responder, sends the signal wave back to the interrogator and then the interrogator. In the communication method using spread spectrum, which despreads the generated signal wave, from the interrogator,
The signal wave is divided into partial chips of the pseudo noise code sequence and transmitted, and a signal wave received after a predetermined time has passed from the transmission is multiplied by the partial chips of the pseudo noise code sequence, and the multiplication result is pseudo noise. It is characterized in that the code sequence is integrated over one cycle or two cycles or more.

According to an eighth aspect of the present invention, the interrogator transmits a signal wave by performing spread spectrum with a pseudo-noise code sequence, receives the signal wave with a transponder, and then sends the signal wave back to the interrogator. In the communication method using spread spectrum, which despreads the generated signal wave, from the interrogator,
For each bit of the Manchester-coded signal wave, a part that is transmitted by dividing it into partial chips of the pseudo-noise code sequence and a part that is transmitted without being divided into partial chips of the pseudo-noise code sequence are combined. It is characterized in that the signal wave transmitted is multiplied by a partial chip of the pseudo noise code sequence after a lapse of a predetermined time from the transmission, and the multiplication result is integrated over one period or two periods or more of the pseudo noise code sequence.

The transmitter / receiver or the interrogator divides the pseudo-noise code sequence into partial chip units for transmission, and the correlator of the transmitter / receiver or interrogator performs multiplication in partial chip units, and the multiplication result is obtained. Correlation calculation is performed by accumulating over one or more pseudo noise code sequences. Therefore, the structure of the correlator can be simplified. Also,
Even if the pseudo-noise code sequence is changed or its code length is changed, the calculation is performed for each partial chip, so that it is not necessary to replace the correlator, and it is possible to handle a long code length.

If the transponder is provided with a delay line,
Since it may be delayed by a partial chip or several partial chips, the delay time due to the delay line is short, the propagation loss due to the delay line can be kept low, and even if the pseudo noise code length is changed, the delay line There is no need to change the delay time. In addition, the responder includes a detector that detects the signal wave from the interrogator, a control circuit that identifies the output from the detector and outputs a data modulation signal, and an interrogator based on the data modulation signal of the control circuit. When a data modulation circuit that performs data modulation on the signal wave is provided, when the transponder sends the signal wave back to the interrogator, the data modulation circuit performs data modulation, so that the interrogator side information is sent to the interrogator. Can be communicated.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a transceiver 1 according to an embodiment of the present invention, and FIG. 2 is a timing diagram inside the transceiver 1. The transceiver 1 exchanges control signals with the outside, and various control signals C1, C
From a control circuit 11 for generating C2, C3, C4, a PN generator 12 for generating a pseudo-noise code sequence PN1, a spread circuit 13 for spread spectrum, an oscillator 14 for oscillating at a microwave band frequency, and a spread circuit 13, respectively. Mixer 15 and mixer 1 for multiplying the output and the output from the oscillator 14
5, an amplifier 16 for amplifying the output of 5, a transmission / reception changeover switch 17 for switching between transmission and reception by a control signal C4, a transmission / reception antenna 18 for transmitting / receiving a signal wave, a transmission / reception antenna 18
The amplifier 19 for amplifying the received signal of 1, the mixer 20 for multiplying the output of the amplifier 19 and the output from the oscillator 14, and the correlator 21. As shown in FIG. 3, the correlator 21 further includes an A / D converter 22, an adder / subtractor 23, and a latch circuit 24.

The PN generator 12 generates a pseudo noise code sequence PN1 divided in units of one chip as shown by PN1 in FIG. 2 according to the control signal C1 from the control circuit 11.
As the pseudo-noise code sequence, for example, M sequence, Barker sequence, Gold sequence, etc. are used, and these are N chips
High level corresponding to code 1 and code -1
It is a low-level pulse train corresponding to (or 0).
The interval between a certain chip and the next chip is for performing reception, which will be described later. In the present embodiment, the chip rate of two clocks is applied as the time for reception.

A baseband signal wave S0 is input to the transmitter / receiver 1 from the outside, and the signal wave S0 is applied to the spreading circuit 1
In FIG. 3, the pseudo noise code sequence PN1 divided from the PN generator 12 in the unit of 1 chip spreads to S1, and the mixer 15, the amplifier 16, and the transmission / reception changeover switch 17 are provided.
The signal is transmitted from the transmitting / receiving antenna 18 as a carrier wave in the microwave band in a state of being divided into 1 chip units.

When the transmission of one chip is completed, the transmission / reception changeover switch 17 is switched to the reception side by the control signal C4 until the transmission of the next chip. The signal wave transmitted in 1-chip units is reflected by a reflector after a predetermined time elapses and is sent back to the transceiver 1 between transmissions in 1-chip units. The signal wave S2 is sent to the correlator 21 via the mixer 20.

A / D converter 22 of correlator 21 shown in FIG.
Then, sampling is performed by the sampling clock S3 in FIG. 2 to perform A / D conversion, and in the adder / subtractor 23, the pseudo-noise code sequence PN1 from the PN generator 12 in 1-chip units.
And the output of the latch circuit 24 are added. The pseudo noise code sequence PN1 is
It may be generated by the PN generator 12, generated by a PN generator separately provided in the correlator 21, or input from the outside. Then, for example, when the voltage level of the pseudo noise code PN is high level, the output of the A / D converter 22 is added to the output of the latch circuit 24, and when the voltage level is low level, the latch circuit 24 is added.
The output of the A / D converter 22 is subtracted from the output of. The output of the adder / subtractor 23 is latched by the latch circuit 24 and then input to the adder / subtractor 23 again to be added / subtracted with the next chip. If this is a signal wave transmitted from the transmitter / receiver 1 and sent back when the pseudo noise code sequence is performed for one cycle or two cycles or more, a significant non-zero correlation value is output from the correlator 21. Become.

In this way, by performing the correlation calculation in the correlator 21 by adding / subtracting on a chip-by-chip basis, the structure of the correlator 21 can be simplified. Even if the pseudo-noise code sequence is changed or its code length is changed, the calculation is performed in the unit of partial chips, so that it is not necessary to replace the correlator 21 itself, and it is possible to cope with a long code length.

In the above embodiment, the sampling frequency of the sampling clock S3 is 2 of the modulation frequency when the timing at which the signal returns is known.
It is less than twice (Nyquist frequency). Next, a second embodiment of the present invention will be described. The second embodiment is shown in FIG.
It is a system for communicating between the interrogator 2 shown in FIG. 2 and the responder 3 shown in FIG.

The interrogator 2 has the same structure as the transceiver 1 shown in FIG. 1, and the same circuits as those in FIG. 1 are designated by the same reference numerals. The interrogator 2 is provided with a second PN generator 26 in addition to the PN generator 12 that generates the pseudo noise code sequence PN1 divided in units of one chip, and the second PN generator 26 is the same as that shown in FIG. , The pseudo noise code sequence PN2 that is not divided for each chip is generated in cycle units, and the two PN generators 12 and 26 output status signals ST1 and ST2 to the control circuit 11, respectively. , The two PN generators 1 according to the control signals C1 and C5 from the control circuit 11 which have received the status signals ST1 and ST2.
2, 26 operations are selected. Hereinafter, transmission using the pseudo noise code sequence PN1 will be referred to as chip transmission, and transmission using the pseudo noise code sequence PN2 will be referred to as block transmission.

The transponder 3 includes a transmission / reception antenna 31 for receiving a signal wave from the interrogator 2, a circular 32 for switching between transmission and reception, a detector 33 for performing envelope detection, a logic circuit 34,
The data modulation circuit 38, the power supply 41, and the delay line 42 are provided. The logic circuit 34 further includes a clock extraction circuit 35, a control circuit 36, and a memory 37. Since the responder 3 of the present embodiment does not include an oscillator, the Manchester code in which the signal wave from the interrogator 2 has a clock component is used to perform clock extraction by the responder 3. In this case, there is a possibility that clock extraction becomes unstable only by chip transmission. Therefore, in the present embodiment, in order to ensure the clock extraction in the transponder 3, transmission in which chip transmission and block transmission are combined is performed.

FIG. 7 shows Manchester-coded transmission waveforms by combining chip transmission and block transmission. FIG. 7 (a) shows data "1" and FIG. 7 (b) shows data "0". In the figure, BL indicates block transmission and CH indicates chip transmission. The signals sent from the interrogator 2 to the responder 3 include a clock synchronization command signal, a CS / ON command signal, a memory access signal and the like. Hereinafter, each signal will be described.

The clock synchronization command signal is used to correctly extract the clock in the responder 3, and the data "0" obtained by combining the chip transmission and the block transmission shown in FIG.
At least 2 bits of "1" or "10" are transmitted. The clock synchronization command signal is envelope-detected by the wave detector 33 and then input to the clock extraction circuit 35. The clock extraction circuit 35 includes a delay circuit 50 as shown in FIG.
And an EX-OR circuit 51, an AND circuit 52, and a multivibrator circuit 53, each signal S5 in FIG.
S6, S7, S8, and S9 have the waveforms shown in FIG. 9, and the correct clock is extracted by sending the clock synchronization command signal “01”.

The clock synchronization command signal becomes unnecessary when the clock can be surely extracted by the PLL or the like on the responder 3 side. Next, the interrogator 2 transmits a CS / ON command signal. This CS / ON command signal is a command for setting CS of the memory 37 to a high level,
The control circuit 36 decodes this command, and the C of the memory 37 is read.
Set the S terminal to high level.

Next, the memory access signal is transmitted from the interrogator 2. This memory access signal is further divided into a command signal, an address signal and a data read signal. The command signal includes a write command for rewriting the contents of the memory 37 of the transponder 3 and a read command for reading the contents of the memory 37. Several kinds of command signals are prepared depending on the pattern of “0” and “1” data. It Then, the contents of the address of the designated memory 37 are changed and read by the combination with the address signal.
For example, when the pattern 0110 *** is sent, the data is read from the address *** of the memory 37 of the responder 3 and sent to the control circuit 36.

The data read signal is a signal which is sent after the command signal and the address signal and is data-modulated by the data modulation circuit 38 according to the data read by the responder 3. The control circuit 36 controls modulation or non-modulation of the data read signal sent from the circular 32 to the data modulation circuit 38 according to the data read from the memory 37. For example, in the case of data 0, no modulation is performed, and in the case of data 1, 180 ° phase modulation is performed.

The data-modulated data read signal is received by the interrogator 2 again after a predetermined time has passed from the transmission of the interrogator 2.
The signal is sent to the correlator 21 via the transmitting / receiving antenna 18 and the mixer 20, and the correlator 21 performs correlation calculation by addition / subtraction for each chip in the same manner as described above to obtain a demodulated signal. FIG. 10 shows a transmission waveform when the responder 3 is accessed using the above commands.

Such a system can be applied to, for example, a system in which the interrogator 2 is mounted on a mobile unit and a plurality of transponders 3 are arranged along the travel route of the mobile unit. By storing the position and the like of the transponder 3 in the memory 37 of each transponder 3, the interrogator 2 confirms the existence of the transponder 3 within the range where the pseudo noise code sequence can be synchronized, and
The data in the memory 37 of the responder 3 is read, and the interrogator 2
You can find out where the is currently.

Further, in the transponder 3 of the present embodiment, the delay line 42 is connected to the data modulation circuit 38. This delay line 42 can ensure the separation of the transmission signal and the reception signal in the interrogator 2 when the interrogator 2 and the responder 3 are within a short distance. A SAW delay line can be used as the delay line 42. At this time, the delay time by the delay line 42 is, for example, 1.
It is preferable to delay the signal by about 5 times and set it so that the interrogator 2 can receive the signal before transmitting the next chip. However, it is not limited to this,
The interrogator 2 may delay the transmission of several chips and then receive the signal several chips before. However, it is necessary to set a delay time such that a response signal can be received between chip-by-chip transmissions, and the start of calculation in the correlator 21 must also be delayed correspondingly. is required.

Conventionally, the pseudo-noise code sequence is divided into blocks of 1
Since a period or two or more periods are collectively transmitted, it is necessary to increase the delay time by the delay line in order to ensure the separation of the transmission signal and the response signal. Therefore, there is a problem that the signal attenuation in the delay line becomes large and the S / N ratio deteriorates as a result. However, in the present embodiment, the delay time by the delay line is 1.5 times the time for transmitting one chip. Since it only needs to be in the order of magnitude, the propagation loss due to the delay line can be suppressed to a low level. Also, the cost of the delay line can be kept low.

In the above-described embodiment, the block transmission and the chip transmission are combined and transmitted to make the baud rate of the transmission data constant so that the transponder can stably extract the clock. A signal may be sent back from the interrogator 2 to the interrogator 2, and only the signal for which the transmitted wave and the received wave need to be separated in the interrogator 2, that is, the data read signal may be transmitted by chip transmission. Conversely, all the command signals may be transmitted by chip transmission using the configuration of the transceiver shown in FIG. 1 as the interrogator and using the responder of FIG.

Further, although the chip transmission is divided for each chip, the invention is not limited to this, and the same applies to the case of dividing for several chips. In addition, the transceiver 1 of FIG.
Although the interrogator 2 has a configuration including the transmission / reception antenna 18, it may have a configuration including a transmission antenna and a reception antenna, respectively. The delay line of the responder 3 can be omitted when the transmission signal and the reception signal can be reliably separated in the interrogator 2.

[0036]

As described above, according to the present invention, the transmitter / receiver or the interrogator transmits the signal wave by dividing the pseudo noise code sequence into partial chips, and transmits the signal wave. Since the correlator performs multiplication in units of partial chips and accumulates the multiplication results over one period of the pseudo noise code sequence, correlation calculation is performed, so that the configuration of the correlator can be simplified.

Further, when the transponder and the reception signal in the interrogator are to be separated by providing a delay line in the transponder,
Since it is sufficient to delay by a partial chip, the delay time due to the delay line is short, and the propagation loss due to the delay line can be suppressed low. Even if the pseudo noise code sequence length used is changed, it is not necessary to change the delay line. Also, the cost of the delay line can be kept low.

The responder has a detector for detecting the signal wave from the interrogator, a control circuit for identifying the output from the detector and outputting a data modulation signal, and the interrogator based on the data modulation signal of the control circuit. When a response signal is sent back to the interrogator, the data modulation circuit performs data modulation when the response signal is sent back to the interrogator. Information can be transmitted.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a transceiver according to an exemplary embodiment of the present invention.

FIG. 2 is a timing diagram within a transceiver.

FIG. 3 is a block diagram showing a configuration of a correlator.

FIG. 4 is a block diagram showing a configuration of an interrogator used in the second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a transponder used in a second embodiment of the present invention.

FIG. 6 is a waveform diagram showing chip transmission and block transmission.

FIG. 7 is a Manchester-transmission waveform diagram in which chip transmission and block transmission are combined, and FIG. 7A shows data “1” and FIG. 7B shows data “0”.

FIG. 8 is a block diagram showing a configuration of a clock extraction circuit.

FIG. 9 is an operation waveform diagram of the clock extraction circuit.

FIG. 10 is a waveform diagram of a command signal transmitted from the interrogator.

[Explanation of symbols]

 1 Transceiver 2 Interrogator 3 Responder 21 Correlator 33 Detector 36 Control circuit 38 Data modulation circuit

Claims (8)

[Claims] 1. A spread spectrum is used in which a signal wave is spread by a pseudo-noise code sequence in a transmitter / receiver and transmitted, and the signal wave is received again by the transmitter / receiver and despread by a correlator of the transmitter / receiver. In the transmitter / receiver, the transmitter / receiver divides the signal wave into sub-chip units of the pseudo noise code sequence and transmits the signal wave, and the correlator,
Spread spectrum is characterized in that a signal wave received after a lapse of a predetermined time from transmission is multiplied by a partial chip of the pseudo noise code sequence, and the multiplication result is integrated over one period or two periods or more of the pseudo noise code sequence. The transceiver used. 2. The interrogator transmits a signal wave by performing spectrum spreading with a pseudo-noise code sequence, receives the signal wave with a transponder, sends the signal wave back to the interrogator, and returns the signal wave with a correlator of the interrogator. In a communication system using spread spectrum, the interrogator divides the signal wave into sub-chip units of the pseudo noise code sequence and transmits the signal wave, and the correlator, after a predetermined time has elapsed from the transmission, A communication system using spread spectrum, characterized in that a received signal wave is multiplied by a partial chip of the pseudo noise code sequence, and the multiplication result is integrated over one period or two or more periods of the pseudo noise code sequence. 3. An interrogator, which transmits a signal wave by performing spread spectrum with a pseudo-noise code sequence, receives the signal wave by a responder, sends the signal wave back to the interrogator, and returns the signal wave by a correlator of the interrogator. In a communication system using spread spectrum that despreads, the interrogator divides the pseudo-noise code sequence into partial chips for each bit of the Manchester coded signal wave, and the pseudo noise The code sequence is transmitted in combination with a part to be transmitted without being divided into partial chips, and the correlator multiplies the signal wave received after a predetermined time has elapsed from the transmission with the partial chip of the pseudo noise code sequence. A communication system using spread spectrum, characterized in that the multiplication result is integrated over one cycle or two cycles or more of the pseudo noise code sequence. 4. The transponder sends a signal wave from the interrogator back to the interrogator through a delay line.
A communication system using the spread spectrum according to claim 2. 5. The responder includes a detector that detects a signal wave from an interrogator, a control circuit that identifies an output from the detector and outputs a data modulation signal, and a response signal based on the data modulation signal of the control circuit. A communication system using spread spectrum according to claim 2, 3 or 4, further comprising: a data modulation circuit that performs data modulation on a signal wave from an interrogator. 6. A transmission method using spread spectrum, in which a signal wave is spread in a transmitter / receiver in a pseudo-noise code sequence and transmitted, and the signal wave is received again in the transmitter / receiver and despread in the transmitter / receiver. From the transmitter / receiver, the signal wave is divided into partial chips of the pseudo-noise code sequence and transmitted, and the signal wave received after a predetermined time has elapsed from the transmission and the partial chip of the pseudo-noise code sequence are multiplied, A transmission method using spread spectrum, wherein the multiplication result is integrated over one period or two or more periods of the pseudo noise code sequence. 7. An interrogator transmits a signal wave by spectrum spreading with a pseudo-noise code sequence, receives the signal wave with a transponder, and then sends it back to the interrogator, and despreads the signal wave sent back with the interrogator. In the communication method using spread spectrum, the interrogator divides the signal wave into sub-chip units of the pseudo noise code sequence and transmits the signal wave, and the signal wave received after a predetermined time has elapsed from the transmission and the pseudo noise code. Characterized in that multiplication with a partial chip of the sequence is performed, and the multiplication result is integrated over one period or two periods or more of the pseudo noise code sequence,
Communication method using spread spectrum. 8. An interrogator transmits a signal wave by performing spectrum spreading with a pseudo-noise code sequence, receives the signal wave with a transponder, and then sends it back to the interrogator, and despreads the signal wave sent back with the interrogator. , In a communication method using spread spectrum, from the interrogator, the portion of the pseudo noise code sequence divided into chip units for each bit of the Manchester coded signal wave and the pseudo noise code sequence The partial wave is transmitted in combination with the part to be transmitted without being divided into chip units, the signal wave received after a predetermined time has passed from the transmission is multiplied by the partial chip of the pseudo noise code sequence, and the multiplication result is calculated as the pseudo noise code sequence 1. A communication method using spread spectrum, characterized by integrating over a period or two or more periods.