JP2001257624A - Spread spectrum communication unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spread spectrum communication unit adopting a simple circuit configuration, which can accurately generate demodulation data. SOLUTION: The spread spectrum communication unit is provided with a generating means that generates a spread spectrum code and a correlation means that detects the correlation between a spread spectrum code of a received signal and a spread spectrum code generated from the generating means and generates two correlation coincidence signals for one period of the spread spectrum code when detecting the correlation coincidence, and with a vanish means that vanishes a specified correlation coincidence signal of the two correlation coincidence signals when adopting a configuration of demodulating the received signal that is subjected to spread spectrum processing by using the correlation coincidence signals, a counter means that counts the number of clock signals by using the correlation coincidence signal not vanished for a reset signal, and a gate means that inhibits input of the clock signal to the count means when the count of the counter means reaches a specified count. Thus, demodulation data are generated from an output terminal of the counter means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum communication device used in spread spectrum communication, and more particularly, to a spread spectrum communication device for realizing accurate demodulation processing.

[0002] Recently, spread spectrum communication has been receiving attention. In this spread spectrum communication, after a carrier wave is first-order modulated with transmission data, the carrier wave is spread using a spread spectrum code (most commonly, having a periodicity of one cycle of one bit section of the transmission data). This feature adopts a configuration that generates a transmission signal by using it, and it can exhibit high confidentiality because it can not be received unless the spread spectrum code is known, and has a small effect on other electronic devices by spreading power. There is.

In order to make this spread spectrum communication practical, it is necessary to construct a practical spread spectrum communication device.

[0004]

2. Description of the Related Art In conventional spread spectrum communication used for consumer use, one type of spread spectrum code (a pseudo-noise code having periodicity, usually
Using an M-sequence cyclic code).
The transmitting side generates a transmission signal by spreading the primary modulation data using the spread spectrum code and transmits the signal to the receiving side. When the receiving side receives the signal from the transmitting side, the receiving side converts the spread spectrum code to the received signal. In this case, the received signal is despread and then demodulated to obtain transmission data.

[0005] At this time, the receiving side uses a SAW convolver or a matched filter that receives the received signal as one input and uses a spread spectrum code whose time direction is opposite to that of the spread spectrum code of the transmission side as the other input. By using the prepared configuration, the received signal and the spectrum prepared for despreading are used by using the correlation coincidence signal detected by the SAW convolver and the matched filter (indicating the coincidence of the spread spectrum code and the coincidence start position). Despreading is performed by synchronizing with a spreading code.

[0006]

However, as in the prior art, there is provided a configuration in which despreading is performed by synchronizing a received signal with a spread spectrum code using a correlation coincidence signal detected by a SAW convolver. If this is adopted, there is a problem that accurate demodulation processing cannot be realized due to fluctuations in the pulse width of demodulated data.

That is, the SAW convolver generates two correlation coincidence signals during one period of the spread spectrum code, because two input signals are input to face each other. It is possible that this becomes one shot. In the prior art, since no countermeasures were taken against this point, the pulse width of the demodulated data sometimes fluctuated.

Further, in the prior art, when a frequency shift occurs between the spread spectrum code for synchronization acquisition and the spread spectrum code on the transmission side, synchronization is obtained using a PLL circuit. At the time of communication, there is also a problem that accurate demodulation processing cannot be realized because this synchronization cannot be maintained.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a new spread spectrum communication device for realizing accurate demodulation processing.

[0010]

1 and 2 show a schematic configuration of the present invention.

In FIG. 1, reference numeral 1 denotes a spread spectrum communication apparatus equipped with the present invention.

The spread spectrum communication apparatus 1 shown in FIG. 1 receives a spread spectrum received signal and demodulates the received signal. The generation means 20, the correlation means 21, and the extinction means 2
2, a counter 23, a gate 24, and a selector 25.

The generating means 20 generates a spread spectrum code. Correlation means 21 is provided for receiving signal 2 and generating means 2
When a correlation with a spread spectrum code in which 0 is generated is detected and a correlation match is detected, two correlation match signals are generated during one cycle of the spread spectrum code. The extinguishing unit 22 extinguishes a prescribed one of the two correlation coincidence signals generated by the correlating unit 21.

The counter 23 counts a clock signal using a correlation coincidence signal which is not erased by the annihilator 22 as a reset signal. The gate 24 prohibits the input of the clock signal to the counter 23 when the count value of the counter 23 reaches the specified value. Selection means 25
When the correlation means 21 outputs a positive / negative correlation coincidence signal in accordance with the primary modulation of the received signal, one of the correlation coincidence signals is selected as valid and input to the annihilation means 22.

In the spread spectrum communication apparatus 1 of the present invention configured as described above, when the correlation means 21 detects a correlation match between the received signal and the spread spectrum code generated by the generation means 20, the correlation means 21 detects the spread of the spread spectrum code. Two correlation coincidence signals are generated during one cycle.

When a SAW convolver is used as the correlating means 21, the correlating means 21 generates a correlation matching signal by primary modulation, for example, when the transmission data value is "0", and when the transmission data is "1", for example. It operates so as not to generate a correlation coincidence signal. Depending on the primary modulation, a correlation coincidence may occur in both of the transmission data values (1 or 0). At this time, the correlation unit 21 receives the support of the selection unit 25, and A state where the correlation match is established in one of them will be created.

In this way, the correlation means 21 generates two correlation coincidence signals during one period of the spread spectrum code according to the transmission data value. , The correlation coincidence signal is 1
In consideration of the fact that only one occurrence occurs, one of the specified ones is eliminated, and the count value of the counter means 23 is reset using a correlation coincidence signal which is not eliminated.

In response to the processing of the annihilation means 22, the counter means 23, for example, when the transmission data is "1", increments the count value in response to the non-occurrence of the correlation coincidence signal, and When the data is "0", the count value is reset at an accurate cycle in response to the generation of the correlation coincidence signal, and the gate means 24 sets the count value when the count value of the counter means 23 reaches the specified value. By inhibiting the input of the clock signal to the counter means 23, the count value is fixed.

According to the counting process, the counter means 23
For example, when the transmission data is “1”, a high level value is output from the specific output terminal, and the transmission data is “0”.
In this case, a low level value is output, and demodulated data is generated.

As described above, the spread spectrum communication apparatus 1 of the present invention shown in FIG. 1 can generate accurate demodulated data while following a simple circuit configuration.

The spread spectrum communication apparatus 1 shown in FIG. 2 receives and demodulates a received signal subjected to spread spectrum, and comprises a first control means 70 and a first despreading means 71.
A second control means 72, a second despreading means 73,
Selection means 74.

The first control means 70 has a function of generating a despread spectrum spread code, and controls the generation timing of the despread spectrum spread code.
Further, the frequency of the despreading spread spectrum code may be controlled in accordance with the PLL method. The first despreading means 71 despreads the received signal using the despreading spread spectrum code generated by the first control means 70.

The second control means 72 includes the first control means 7
It has a function of generating a despread spectrum spread code in a form independent of 0, and controls the frequency of the despread spectrum spread code according to the DLL method. The second despreading means 73 despreads the received signal using a despreading spread spectrum code generated by the second control means 72. The selecting means 74 selects one of the output signal of the first despreading means 71 and the output signal of the second despreading means 73.

In the spread spectrum communication apparatus 1 of the present invention configured as described above, the first control means 70 detects the correlation between the received signal and the received spread spectrum code to thereby prepare the reverse signal. The generation timing of the spread spectrum spread code is controlled, and if necessary, the PLL
The frequency of the despreading spread spectrum code is controlled according to the method. Then, in response to this, the first despreading means 71 despreads the received signal using the despread spectrum spreading code generated by the first control means 70.

On the other hand, the second control means 72 controls the generation timing of the prepared spread spectrum code for despreading according to the correlation detection result of the first control means 70,
The frequency of the despread spectrum spread code is controlled according to the DLL method. Then, in response to this, the second despreading means 73 despreads the received signal using the despread spectrum spreading code generated by the second control means 72.

In response to these despreading processes, selection means 7
The fourth characteristic is that the first control means 70 performs synchronization acquisition using the PLL method, so that synchronization can be acquired at a higher speed than the second control means 72 which performs synchronization acquisition using the DLL method. While the second control means 72 is DL
By performing the synchronization acquisition using the L system, the first control unit 70 that performs the synchronization acquisition using the PLL system has a characteristic that the acquired synchronization can be held for a longer time than the first control means 70. , The output signal of the first despreading means 71 is selected, and then, when the second control means 72 completes synchronization acquisition, the output signal of the second despreading means 73 is selected.

When the selection means 74 has selected the output signal of the second despreading means 73, the first control means 70 performs processing to start the synchronization acquisition processing of the next spread spectrum code.

As described above, in the spread spectrum communication apparatus 1 of the present invention shown in FIG. 2, the synchronization with the received signal is acquired at high speed by using the PLL system, and the synchronization is accurately performed for a long time by using the DLL system. Because it adopts the configuration to keep,
An accurate demodulation process can be realized.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail according to embodiments.

First, the present invention (hereinafter, sometimes referred to as the first invention) whose schematic configuration is shown in FIG. 1 will be described.

The spread spectrum communication apparatus 1 according to the first invention performs a process of receiving and demodulating a received signal subjected to spread spectrum, and has a configuration for directly generating demodulated data from a correlation coincidence signal output from a SAW convolver. take.

In spread-spectrum communication, a carrier is first-modulated with transmission data and then spread with a spread-spectrum code.

As the primary modulation, frequency modulation (FS)
K) may be used. In this case, the center frequency of the SAW convolver differs depending on whether the transmission data is “1” or “0”. From this, the SAW convolver outputs a correlation matching signal when the transmission data value matches the center frequency (for example, “0”), and outputs the correlation matching signal when the transmission data value does not match the center frequency (for example, “1”). Operate so as not to output.

As the primary modulation, phase modulation (PS
K) may be used. In this case, different spread-spectrum codes are used for the transmission data value "1" and the transmission data value "0", and the receiving side may perform despreading using one of them. , SAW
The convolver outputs a correlation match signal when the transmission data value matches the spread spectrum code (for example, “0”), and outputs a correlation match signal when the transmission data value does not match the spread spectrum code (for example, “1”). Not to work.

As described above, the operation of the SAW convolver can be defined such that the correlation match signal is output when one of the transmission data values is output and the correlation match signal is not output when the other transmission data value is output.

When the SAW convolver performs such an operation, for example, as shown in FIG. 3, while the correlation coincidence signal is being output, a pulse indicating a low level is output. By outputting a pulse indicating a high level, a received signal can be demodulated.

According to the first invention, according to this mechanism, SA
In this configuration, demodulated data is directly generated from the correlation coincidence signal output from the W convolver. At this time, the correlation coincidence signal generates two correlation coincidence signals during one period of the spread spectrum code (that is, during one transmission data value). One shot happens. The first invention adopts a configuration in which demodulated data is directly generated from the correlation coincidence signal output from the SAW convolver while taking this point into consideration.

FIG. 4 shows an embodiment of the first invention.

As shown in this figure, a spread spectrum communication apparatus 1 according to the first invention has a clock generation circuit 200 for generating a clock signal for generating a spread spectrum code.
Then, using the clock signal generated by the clock generation circuit 200, a spread spectrum code for reception (the direction of time is opposite to that of the spread spectrum code on the transmission side) is generated and generated by a local oscillator (not shown). A reference signal generator 201 that generates a reference signal by multiplying the received signal by a carrier signal generated by a local oscillator (not shown). A SAW convolver 203 that receives a generated reference signal and an output signal of the down converter 202 and outputs two correlation coincidence signals during one cycle of the spread spectrum code;
A detection circuit 204 for detecting a correlation coincidence signal output from the convolver 203 and a demodulation circuit 205 for generating demodulated data of a received signal from a clock signal generated by the clock generation circuit 200 and an output signal of the detection circuit 204 are provided.

Here, in the detection circuit 204, the SAW convolver 203 sometimes outputs a correlation match signal for both the transmission data value “1” and the transmission data value “0”. Is output in accordance with the following equation, so that the correlation coincidence signal having a negative sign is erased, so that the correlation coincidence signal is output only in one of the transmission data values. Is provided.

For example, as primary modulation, phase modulation (PS
When using K), the same spread spectrum code may be used for the transmission data value "1" and the transmission data value "0". In this case, the transmission data value "1" and the transmission data value "0" are used. , The correlation coincidence signal is output, and the detection circuit 204 is used to erase the correlation coincidence signal having a negative sign.

A demodulation circuit 205 for generating demodulated data of a received signal includes a counter 206 and an
D circuit 207, comparator 208, AND circuit 2
09.

The counter 206 counts the clock signal generated by the clock generation circuit 200. The AND circuit 207 receives the clock signal generated by the clock generation circuit 200 and the inverted value of the signal value of the most significant bit of the counter 206, calculates the logical product of the two input values, and Input to the terminal.

The comparator 208 outputs a high level when the count value of the counter 208 indicates a time slightly longer than a half cycle of the spread spectrum code, and outputs a low level when the count value does not reach that. . The AND circuit 209 receives the correlation matching signal output from the detection circuit 204 and the output signal of the comparator 208 as inputs, calculates the logical product of these two input values, and outputs the logical product to the reset terminal of the counter 206.

In the first embodiment of the present invention configured as described above, the AND circuit 209 receives the high level output of the comparator 208 and outputs the correlation coincidence signal to the counter 206 when the detection circuit 204 outputs the correlation coincidence signal. A reset instruction is issued for this. As a result, the count value of the counter 206 becomes “0”, the comparator 208 outputs a low level, the signal value of the most significant bit of the counter 206 becomes “0”, and the AND circuit 207 generates the clock. The clock signal generated by the circuit 200 is
Enter 6

Upon receiving the clock signal from the AND circuit 207, the counter 206 starts counting. At the time of this counting, the detection circuit 204 outputs the second correlation coincidence signal (the second correlation coincidence signal generated during one cycle of the spread spectrum code). , The low level is still output, and the AND circuit 209 ignores the second correlation match signal.

As the counting of the counter 206 progresses, the comparator 208 outputs a high level.
The ND circuit 209 issues a reset instruction to the counter 206 when the detection circuit 204 outputs the next correlation coincidence signal.

As described above, when the detection circuit 204 is outputting the correlation coincidence signal, before the signal value of the most significant bit of the counter 206 turns to "1", the counter 20
Since the count value of 6 is reset to "0", the signal value of the most significant bit of the counter 206 remains at the low level.

In this operation, when the detection circuit 204 stops outputting the correlation coincidence signal, the AND circuit 209 stops issuing the reset instruction to the counter 206. From now on, the counter 206 counts up the count value, and when the count advances, the signal value of the most significant bit of the counter 206 changes to “1”, whereby the AND circuit 207 causes the counter 206 Stop signal input. As a result, the signal value of the most significant bit of the counter 206 remains at the high level. At this time, the comparator 208 outputs a high level.

At the time of this operation, the detection circuit 2
04 starts outputting the correlation coincidence signal, the counter 206 is repeatedly reset while repeating the process of ignoring one of the correlation coincidence signals output from the detection circuit 204 according to the above-described operation. A state is created in which the signal value of the most significant bit of 206 still indicates a low level.

As described above, in the spread spectrum communication apparatus 1 according to the first aspect of the present invention, for example, the most significant bit of the counter 206 indicates a low level while the SAW convolver 203 is outputting the correlation coincidence signal, By outputting demodulated data indicating a high level while a match signal is not output, a transmission data value that outputs a correlation match signal indicates a low level, and a transmission data value that does not output a correlation match signal indicates a high level. It generates demodulated data.

In addition, at this time, a configuration is employed in which demodulated data is generated while ignoring one of the provisions of two correlation coincidence signals generated during one cycle of the spread spectrum code. As shown in the time chart, even if only one correlation coincidence signal occurs due to timing or the like, demodulated data can be accurately generated. Here, in FIG. 5, 'is an output signal of the detection circuit 204, is an output signal of the comparator 208, and is
The output signal of the circuit 209 indicates the signal value of the most significant bit of the counter 206.

Next, a description will be given of the present invention (hereinafter, sometimes referred to as a second invention) whose schematic configuration is shown in FIG.

The spread spectrum communication apparatus 1 according to the second invention receives and demodulates a received signal subjected to spread spectrum.

FIG. 6 shows an embodiment of the second invention.

As shown in the figure, a spread spectrum communication apparatus 1 according to the second invention captures synchronization with a received signal using a PLL system and executes a despreading process.
A synchronization acquisition mechanism 700, a DLL synchronization acquisition mechanism 750 for acquiring synchronization between the received signal using the DLL method and executing a despreading process, and a PLL synchronization acquisition mechanism 700 / DLL
PN controller 800 for controlling synchronization acquisition mechanism 750
And a selection circuit 900 for selectively outputting either the output signal of the PLL synchronization acquisition mechanism 700 or the output signal of the DLL synchronization acquisition mechanism 750.

The PLL synchronization acquisition mechanism 700 includes a despreading PN generating circuit 701 and a receiving PN generating circuit 702.
, A correlator 703, a VCO circuit 704, a PLL circuit 705, and a multiplier 706.

The despreading PN generating circuit 701 generates a despreading spread spectrum code. The reception PN generation circuit 702 is a reception spread spectrum code (the time direction is opposite to that of the despread spectrum spread code).
Occurs. The correlator 703 is configured by a SAW convolver or a matched filter, and detects a correlation between the received signal and the spread spectrum code generated by the receiving PN generating circuit 702.

The VCO circuit 704 is constituted by a voltage controlled oscillator, and controls the frequency of a clock for generating a spread spectrum code to be supplied to the despreading PN generating circuit 701.
The PLL circuit 705 controls the frequency control voltage applied to the VCO circuit 704 by comparing the phase between the output clock of the VCO circuit 704 and the correlation coincidence signal detected by the correlator 703. Multiplier 706 despreads the received signal using the spread spectrum code generated by despreading PN generation circuit 701.

On the other hand, the DLL synchronization acquisition mechanism 750 includes a despreading PN generation circuit 751, a first synchronization acquisition PN generation circuit 752, a first multiplier 753, and a second synchronization acquisition PN generation circuit. 754, a second multiplier 755, a differentiator 756, a VCO circuit 757, and a DLL circuit 758.
And a despreading multiplier 759.

The despreading PN generating circuit 751 generates a despreading spread spectrum code. The first synchronization acquisition PN generation circuit 752 is a despreading PN generation circuit 75.
A spread-spectrum code that is one cycle ahead of the spread-spectrum code generated by 1 is generated. The first multiplier 753 calculates a multiplication value of the received signal and a spread spectrum code generated by the first synchronization acquisition PN generation circuit 752.

The second synchronous PN generation circuit 754 includes:
It generates a spread spectrum code that is delayed by one cycle in time from the spread spectrum code generated by the despreading PN generation circuit 751. The second multiplier 755 calculates a multiplication value of the received signal and a spread spectrum code generated by the second synchronization acquisition PN generation circuit 754.

The differentiator 756 calculates a difference value between the output signal of the first multiplier 753 and the output signal of the second multiplier 755. The VCO circuit 757 is configured by a voltage controlled oscillator and controls the frequency of a clock for generating a spread spectrum code to be supplied to the despreading PN generation circuit 751. DL
The L circuit 758 controls a frequency control voltage applied to the VCO circuit 757 from the output signal of the differentiator 756. The despreading multiplier 759 despreads the received signal using the spread spectrum code generated by the despreading PN generation circuit 751.

In the spread spectrum communicator 1 according to the second aspect of the present invention, the PN controller 800
Despreading PN generating circuit 701 / receiving PN generating circuit 70
2 / Control is performed so that the despreading PN generation circuit 751 generates a spread spectrum code used on the transmission side. When the despreading PN generating circuit 701, the receiving PN generating circuit 702, and the despreading PN generating circuit 751 generate an M-sequence cyclic code as a spread spectrum code according to the circuit configuration shown in FIG. This is done by switching.

Here, the circuit for generating the cyclic code of the M-sequence shown in FIG. 7 is composed of six delay elements and an adder for executing addition of mod2, and x ⁶ + x + 1 = 0 x ⁶ + x ^{5 + 1 = 0 x 6 +} x 5 + x 2 + x + 1 = 0 x 6 + x 5 + x 3 + x 2 + 1 = 0 x 6 + x 4 + x 3 + x + 1 = 0 x 6 + x 5 + x 4 + x + 1 = 0 6 types derived from the formula of Generate the cyclic code of.

FIGS. 8 and 9 show these six types of M-sequence cyclic codes. As shown in this figure, these six types of M-sequence cyclic codes have 63 cycles as one cycle. As can be seen from this figure, the cyclic codes identified by (a) and (b) The cyclic code identified has the same periodic pattern in which the time direction is opposite, and the cyclic code identified in (c) and the cyclic code identified in (f) have the opposite time direction. The cyclic code identified by (d) and the cyclic code identified by (e) have the same periodic pattern
It has the same periodic pattern in which the direction of time is reversed.

Thus, the receiving PN generating circuit 70
2 generates a spread spectrum code, the correlator 703 detects a correlation between the received signal and the spread spectrum code generated by the reception PN generation circuit 702,
When a correlation match is detected, a correlation match signal is generated and output to the PLL circuit 705 and the PN controller 800.

Upon receiving the correlation coincidence signal, the PN controller 800 causes the despreading PN generation circuit 701 and the despreading PN generation circuit 751 to generate a spread spectrum code in synchronization with the correlation coincidence signal. And control. When despreading PN generating circuit 701 / despreading PN generating circuit 751 generates an M-sequence cyclic code as a spread spectrum code according to the circuit configuration shown in FIG. 7, the corresponding initial value is set. Do this.

The PLL circuit 705 includes a correlator 70
When the correlation match signal is received from the VCO circuit 704, the voltage value for frequency control given to the VCO circuit 704 is determined by comparing the phase of the correlation match signal with the output clock of the VCO circuit 704. VCO circuit 704 receives PN voltage for despreading,
Generates a clock while controlling the frequency of the clock and supplies it to the despreading PN generation circuit 701 so as to generate a spread spectrum code having the same frequency as the spread spectrum code used on the transmission side.

Thus, the despreading PN generating circuit 7
01 generates a spread spectrum code including the frequency in synchronization with the spread spectrum code used on the transmission side.
The received signal is despread using the spread spectrum code generated by 01.

On the other hand, when the despreading PN generating circuit 751 generates a spread spectrum code in synchronization with the correlation coincidence signal detected by the correlator 703 according to the processing of the PN controller 800, the first synchronization capturing PN is generated. The generation circuit 752 generates a spread spectrum code which is one cycle ahead of the spread spectrum code generated by the despreading PN generation circuit 751, and in response, the first multiplier 753 outputs the received signal and the received signal. A multiplication value with the spread spectrum code generated by the first synchronization acquisition PN generation circuit 752 is calculated.

The second synchronous acquisition PN generation circuit 75
4 generates a spread spectrum code which is delayed by one cycle from the spread spectrum code generated by the despreading PN generating circuit 751 and receives the generated spread spectrum code.
55 is a PN generation circuit for synchronizing the received signal with the second
The multiplication value with the spread spectrum code generated in step No. 4 is calculated.

The first and second multipliers 753, 755
, The differentiator 756 generates the first multiplier 753
And the output signal of the second multiplier 755 are calculated. In response to the difference value, the DLL circuit 758 determines a voltage value for frequency control to be given to the VCO circuit 757 from the difference value, and receives the determined frequency control voltage to Generates a clock while controlling the clock frequency so that the despreading PN generation circuit 751 generates a spread spectrum code having the same frequency as the spread spectrum code used on the transmission side. PN generation circuit 751.

As described above, the despreading PN generation circuit 7
51 generates a spread-spectrum code in synchronization with the spread-spectrum code used on the transmission side, including the frequency, so that the despreading multiplier 759 generates the spectrum generated by the despreading PN generation circuit 751. Despread the received signal using a spreading code.

As described above, the PLL synchronization acquisition mechanism 700
Uses the PLL method to capture synchronization with the received signal and performs despreading processing.
Using the DLL method, synchronization with the received signal is acquired and despreading processing is performed.

As is well known, the PLL method is
There is a characteristic that the synchronization can be acquired at a higher speed than the DLL system, and the DLL system has a characteristic that the acquired synchronization can be held for a longer time than the PLL system.

From this, the selection circuit 900 first selects the output signal of the PLL synchronization acquisition mechanism 700 in consideration of this characteristic, and thereafter, when the synchronization acquisition of the DLL synchronization acquisition mechanism 750 is completed, the DLL synchronization acquisition A process of selecting an output signal of the mechanism 750 is performed.

Further, the DLL synchronization acquisition mechanism 750 includes a PN
According to the processing of the controller 800, when the despreading PN generation circuit 751 generates a spread spectrum code in synchronization with the correlation coincidence signal detected by the correlator 703 as an initial state, the correlation coincidence signal is not used thereafter. .

From this, when the selection circuit 900 enters the process of selecting the output signal of the DLL synchronization acquisition mechanism 750, the PN controller 800 sets the PN for despreading to enter the process of the next spread spectrum code used on the transmission side. Generator 7
01 / Reception PN generation circuit 702 controls to generate the spread spectrum code, and in response thereto, PLL synchronization acquisition mechanism 750 can start synchronization acquisition of the spread spectrum code. With this configuration, a parallel operation of synchronization acquisition can be performed.

As described above, in the spread spectrum communication apparatus 1 of the second invention, the synchronization with the received signal is acquired at high speed by using the PLL system, and the synchronization is accurately maintained for a long time by using the DLL system. With this configuration, accurate demodulation processing can be realized.

At the time of realizing the second invention,
In the embodiment shown in FIG.
PN generator for despreading 701 / PN for reception
If the frequency of the spread-spectrum code generated by the generation circuit 702 matches the transmission-side code with high accuracy, FIG.
As shown in FIG.
It is also possible to adopt a configuration in which the O circuit 704 / PLL circuit 705 is deleted.

[0082]

As described above, according to the first aspect of the present invention, it is possible to generate accurate demodulated data while following a simple circuit configuration.

According to the second aspect of the present invention, P
Since the synchronization with the received signal is captured at high speed by using the LL system and the synchronization is accurately maintained for a long time by using the DLL system, accurate demodulation processing can be realized.

As described above, according to the present invention, it is possible to realize a spread spectrum communication device that realizes accurate demodulation processing.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of the present invention.

FIG. 2 is a schematic configuration diagram of the present invention.

FIG. 3 is an explanatory diagram of the first invention.

FIG. 4 is an embodiment of the first invention.

FIG. 5 is a time chart of the first invention.

FIG. 6 is an embodiment of the second invention.

FIG. 7 is an explanatory diagram of generation of an M-sequence cyclic code.

FIG. 8 is an explanatory diagram of generation of an M-sequence cyclic code.

FIG. 9 is an explanatory diagram of generation of an M-sequence cyclic code.

FIG. 10 shows another embodiment of the second invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spread spectrum communication apparatus 20 Generating means 21 Correlation means 22 Elimination means 23 Counter means 24 Gate means 25 Selection means 70 First control means 71 First despreading means 72 Second control means 73 Second despreading means 74 Selection means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaki Arai 98 Unouki-nu, Unoki-cho, Hebei-gun, Ishikawa Pref. No. 2 Inside PFU Co., Ltd.

Claims (6)

[Claims] An apparatus for generating a spread spectrum code, detecting a correlation between a received signal and a spread spectrum code generated by the generation means, and detecting one cycle of the spread spectrum code when detecting a correlation match. A correlation means for generating two correlation coincidence signals between the two, and a spread spectrum communication apparatus for demodulating a spread spectrum received signal using the correlation coincidence signal detected by the correlation means. Erasing means for erasing a prescribed one of two generated correlation coincidence signals; counter means for counting clock signals using a correlation coincidence signal which is not erased by the erasure means as a reset signal; When the number reaches the specified value,
A spread-spectrum communication device, comprising: gate means for inhibiting input of a clock signal to the counter means; and generating demodulated data from an output terminal of the counter means. 2. The spread spectrum communication apparatus according to claim 1, wherein when the correlation means outputs a positive / negative correlation coincidence signal in accordance with the primary modulation of the received signal, any one of the correlation coincidence signals is output. A spread spectrum communication device, comprising: selection means for selecting a valid one. 3. The spread spectrum communication apparatus according to claim 1, wherein said quenching means detects whether or not the count value of said counter means has reached a reference value, and said detecting means detects said counting means. A spread-spectrum communication apparatus, comprising: a gate means for receiving the result and the output signal of the correlation means as inputs, and prohibiting passage of the output signal when the comparison means detects non-arrival. . 4. A spread-spectrum communication device for receiving a spread-spectrum received signal, the spread-spectrum communication device having a function of generating a spread-spectrum code for despreading, and determining a correlation between the received signal and the received spread-spectrum code. First control means for controlling the generation timing of the despreading spread spectrum code by detecting the received signal, and despreading the received signal using the despreading spread spectrum code generated by the first control means. A first despreading means for generating a spread-spectrum code for despreading in a manner independent of the first control means, and according to a correlation detection result of the first control means, A second control means for controlling the frequency of the despread spectrum spreading code according to the DLL system while controlling the generation timing of the despreading spread spectrum code; A second despreading means for despreading a received signal by using a despreading spread spectrum code generated by the second control means; and an output signal of the first despreading means or the second despreading means. Selecting means for selecting any one of the output signals of the spreading means. 5. The spread spectrum communication apparatus according to claim 4, wherein said first control means also controls the frequency of a despread spectrum spread code in accordance with a PLL system. . 6. The spread spectrum communication apparatus according to claim 4, wherein said first control means selects a next spread spectrum signal when said selection means selects an output signal of said second despreading means. A spread-spectrum communication apparatus characterized in that processing is performed so as to enter a synchronization acquisition processing of a spread code.