JPH08125581A - Spectrum spreading device - Google Patents

Abstract

PURPOSE: To attain spectrum spreading with high precision by facilitating presence or absence of correlative judgement and quickly detecting a Doppler frequency. CONSTITUTION: Through the use of two kinds of intermediate frequencies generated in oscillators 21 and 35, the first intermediate frequency is adopted as the high frequency for spreading/reverse spreading in a transmitting part 20 and the second intermediate frequency is set to be the one lower than the first intermediate frequency in a receiving part 30. When correlation is obtained by reverse spreading, the power of the second intermediate frequency is detected and wave-detected by the demodulator 41 of a correlation detecting part 40 so that correlation is judged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum device used for mobile communication and distance measurement of mobiles.

[0002]

2. Description of the Related Art Heretofore, a plurality of spread spectrum devices of this type have been proposed for performing communication with a moving body and distance measurement of the moving body using a spread spectrum system. Particularly, in mobile communication, one using a relatively low frequency (about 2.4 GHz) is being put to practical use, and in distance measurement of a mobile, it is disclosed in, for example, Japanese Unexamined Patent Publication No. 5-256936. Thus, there has been proposed a forward monitoring radar that detects an obstacle in the forward direction of a vehicle.

[0003]

However, in mobile communication, the millimeter wave band (for example, 60 GHz band) is expected to be used in the future, and as the frequency becomes higher, it becomes difficult to judge the presence or absence of correlation. The Doppler frequency resulting from the relative speed between transmission and reception was also high. For example, when the relative speed is 100 km / h, the Doppler frequency of 2.4 GHz is about 200 Hz, whereas the Doppler frequency of 60 GHz is about 5.5 KHz, which adversely affects data demodulation when used for communication. There was a problem of affecting.

Further, the radar disclosed in Japanese Patent Laid-Open No. 5-256936 has a problem that it takes time to adjust the Doppler frequency because it is not known which of the Doppler frequencies is oscillating. Further, the Doppler frequency has a problem that the frequency is low and it takes time to measure. In the spread spectrum system, a pseudo noise code (hereinafter referred to as “PN code”) composed of a bit string (epoch) of a certain unit is used to spread a certain frequency at the transmitter and despread at the receiver. This despreading has a property that the spectrum is concentrated only when the transmitted PN code and the received PN code match (when the correlation is obtained). When determining this correlation, there is a method in which the spectrum is processed by FFT (Fast Fourier Transform) to detect the power. However, this is not affected by the Doppler frequency, but a high-precision AD converter or a high-speed AD converter is used. DS
Since P (digital signal processor) or the like is required, there is a problem that the manufacturing cost is high.

The present invention has been made in view of the above problems, and it is an object of the present invention to make it easy to determine the presence or absence of a correlation, to quickly detect a Doppler frequency, and to perform spectrum spread with high accuracy.

[0006]

In order to achieve the above object, in claims 1 and 2, a pseudo noise signal generating means for transmission, which comprises a signal processing part for generating a pseudo noise signal for transmission, and a first intermediate frequency are provided. The first oscillating means for oscillating the first intermediate frequency, the frequency spreading means comprising a spreader for spreading the first intermediate frequency by the pseudo noise signal for transmission, and the spread first intermediate frequency radio frequency Radio frequency conversion means including a frequency converter and a transmission antenna for converting and transmitting to a band, a reception antenna and a frequency conversion for receiving a reception signal of the radio frequency band and converting the reception signal into the first intermediate frequency band And a receiving pseudo-noise signal generating means including a signal processing unit that generates the same receiving pseudo-noise signal as the transmitting pseudo-noise signal, and the receiving pseudo-noise signal generating means. When the correlation is a well-like noise signal and the received signal, and despreading means comprising a despreader to concentrate diffused frequency to a first intermediate frequency, said first
Based on an output from the second oscillating means, the second oscillating means comprising an oscillator that oscillates a frequency of a difference between the intermediate frequency of 1 and a second intermediate frequency lower than the first intermediate frequency, There is provided a spread spectrum device comprising: a second conversion means including a frequency converter for converting the concentrated first intermediate frequency into a second intermediate frequency.

According to a third aspect of the present invention, a third oscillating means that oscillates at the same frequency as the second intermediate frequency and is capable of changing the frequency, and an output from the third oscillating means are divided into two. Phase shift means for shifting the output phase by a predetermined angle and outputting it, and I frequency for frequency-converting by multiplying the second intermediate frequency converted by the frequency converting means and one output whose phase is not shifted. Q for frequency conversion by multiplying the conversion means and the second intermediate frequency converted by the frequency conversion means by one output of which the phase is shifted
And frequency conversion means.

According to a fourth aspect of the present invention, there is provided multiplication means for multiplying the output of the I frequency conversion means and the output of the Q frequency conversion means, and level changing means for changing the output level according to the output of the multiplication means. The third oscillating means changes the frequency based on the output level. Claims 5 and 6
Then, the first 2 which squares the output of the I frequency conversion means
And a second means for squaring the output of the Q frequency conversion means.
Square means, an adding means for adding the outputs of the respective square means, and an integrating means for integrating the added outputs.

According to the present invention, the judgment means for judging the potential sign of the outputs of the I frequency conversion means and the Q frequency conversion means, and the output of the I frequency conversion means and the Q frequency conversion means based on the judgment result. A detection means for detecting the potential sign of the Doppler frequency. In claim 9,
Judgment means for judging the potential sign of the output of the I frequency conversion means and Q frequency conversion means, operation means for performing a logical operation of each output, and the I frequency conversion means and Q frequency conversion means based on the operation result. Detecting means for detecting the Doppler frequency generated in the output of the.

[0010]

According to the first aspect of the present invention, one kind of intermediate frequency is used.
Since the intermediate frequency of is spread / despread, a high frequency is set. When the correlation is obtained by despreading, the correlation is judged by detecting the power of the first intermediate frequency. Claim 2
Then, two kinds of intermediate frequencies are used, the first intermediate frequency is set to a high frequency for spreading / despreading, and the second intermediate frequency is set to a frequency lower than the first intermediate frequency. When the correlation is obtained by despreading, the correlation is judged by detecting the power of this second intermediate frequency.

In the third aspect, the same frequency as the second intermediate frequency is used for detection by the IQ demodulator to extract the DC component from I and Q. In claim 4, the frequency of the IQ demodulator is finely adjusted so as to cancel the Doppler frequency. According to the fifth aspect, the DC component is squared and the presence or absence of correlation can be determined by the output level.

In a sixth aspect of the present invention, the direct current component is squared to obtain 1
Integrating between epochs enables the presence of correlation. According to claim 8, the level of the output waveform of one of the output waveforms from I and Q when 0V is crossed is determined to determine whether it is the approaching Doppler frequency or the approaching Doppler frequency. .

In the ninth aspect, the Doppler frequency is detected in 1/4 cycle based on the pulse width which is the calculation result.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a spread spectrum device according to the present invention will be described with reference to the drawings of FIGS. Figure 1
It is a block diagram which shows the structure of one Example of the spread spectrum apparatus which concerns on this invention. In this embodiment, first, two types of intermediate frequencies are prepared in order to make it easier to detect the power of the despread spectrum. The first intermediate frequency requires a certain high frequency for spreading / despreading, and for example, in the case of a spread spectrum system using a band of 500 MHz, a frequency of about 1 GHz is required. The second intermediate frequency is a low frequency that is easier to handle than the first intermediate frequency, here, for example, AGC (auto
(Gain control) Set to a frequency (about 50 to 100 MHz) suitable for the amplifier and the oscillator whose frequency can be accurately changed by the Doppler frequency as described later. If the correlation is obtained by despreading, the first and second
Since the power of the intermediate frequency is increased, the correlation can be determined by detecting the power.

In FIG. 1, the spread spectrum apparatus according to the present embodiment is used for mobile communication, a signal processing section 10 for performing signal processing on various signals, a transmission section 20 for transmitting radio waves by a spread spectrum method. In the case of being used as a radar, the reception unit 30 receiving a reflected wave from a moving body (not shown) and the correlation by the principle of the spread spectrum system are detected. And a correlation detection unit 40 that

In the transmitter 20, the oscillator 21 has a high frequency of 1 GHz for spreading / despreading.
When generating a first intermediate frequency of the order of magnitude and using it as a communication device, the first intermediate frequency is applied to the modulator 2
2 and when used as a radar device, the modulator 22 becomes unnecessary and the first intermediate frequency is directly spread by the spreader 2
3 is sent.

The modulator 22 modulates the first intermediate frequency with the transmission data input from the signal processing unit 10, and outputs the modulated first intermediate frequency to the spreader 23.
The spreader 23 is realized by a ring modulator having a mixing function in the case of a communication device, and is realized by a multiplier, that is, an arithmetic unit for adjusting a frequency in the case of a radar device, and the signal processor 10 is used. The first intermediate frequency is spread by the transmission PN code input from. That is, in order to briefly describe the operation of the spreader 23, the case of a radar device will be described. The spreader 23 receives the transmission PN code of the spectrum shown in FIG. A spectrum (see FIG. 2B) in which the spectrum of the transmission PN code appears on both sides around the first intermediate frequency is output. In the spectrum shown in FIG. 2, the horizontal axis represents frequency and the vertical axis represents power.

In order to transmit the output of the spectrum as a radio wave, a transmission antenna may be connected to the spreader 23. However, in spread spectrum which requires a wide band spectrum, the frequency of the radio wave should be as high as possible. desirable. In particular, at present, the millimeter wave band, which has various merits, is drawing attention. In this embodiment, the frequency converter 24 is connected to the spreader 23 in order to use radio waves in this frequency band.

An oscillator 25 for generating a radio frequency is connected to the frequency converter 24, and the frequency converter 24
Shifts the output of the spreader 23 to the higher side by the radio frequency input from the oscillator 25, and transmits it as a radio wave of the spectrum shown in FIG. In the receiving section 30, a frequency converter 32 is connected to the receiving antenna 31, and the frequency converter 32 transmits the radio wave (see FIG. 2 (c)) received by the receiving antenna 31 to the first intermediate signal. It is converted to the frequency band and the spectrum is output as shown in FIG.

Despreader 3 connected to frequency converter 32
3 has a mixing function similar to that of the diffuser 23. The despreader 33 has a PN for transmission from the signal processing unit 10.
A receiving PN code having the same configuration as the code is input, and the despreader 33 despreads (concentrates) the output from the frequency converter 32 with the receiving PN code. That is, when the transmission PN code and the reception PN code string match, that is, when the correlation is obtained, the spectrum of the output of the despreader 33 has the first intermediate frequency as shown in FIG. 2 (d). There is a sharp peak. Further, when the transmission PN code and the reception PN code string do not match, that is, when the correlation cannot be obtained, the spectrum of the output of the despreader 33 is as shown in FIG.
As shown in, the sharp peak at the first intermediate frequency disappears. Originally, it is possible to determine whether or not the correlation is obtained by measuring the power of the spectrum of the first intermediate frequency, but it is difficult to detect the power as it is because the first intermediate frequency is also high to some extent. Therefore, a frequency converter 34 composed of a mixer is connected to the despreader 33 so that the first intermediate frequency becomes lower (50
To a second intermediate frequency of about 100 MHz).

The frequency converter 34 is connected with an oscillator 35 for generating a frequency of the difference between the first intermediate frequency and the second intermediate frequency, and the frequency converter 34 receives the second frequency input from the oscillator 35. The first intermediate frequency is converted to the second intermediate frequency by the intermediate frequency of
The power of the spectrum output from the frequency converter 34 (see FIG. 2 (f)) also follows the power of the spectrum of the first intermediate frequency.

In the correlation detector 40, the quadrature demodulation circuit (I-Q demodulation circuit) 41 divides the output from the AGC 41a and an oscillator 41i described later into two, as shown in the first embodiment of FIG. Shifter 41b for shifting and outputting the phase of 90 ° by 90 °, I frequency converter 41c and Q frequency converter 41d connected to AGC 41a and phase shift distributor 41b, and frequency converters 41c, 41d
And low-pass filters 41e, 41f connected to the multiplier 41 for multiplying the frequencies from the filters 41e, 41f.
g and a multiplier 41g, which is a loop filter 4 that changes the output level according to the frequency that is the multiplication result.
1h, and an oscillator 41i that adjusts the frequency based on the output from the loop filter 41h and outputs it to the phase shift distributor 41b.

The IQ demodulation circuit 41 performs detection using the same frequency as the second intermediate frequency, and extracts the detection signal from the I and Q terminals. The detection signals at the I and Q terminals are expressed by the following equation. Here, the input of the IQ demodulation circuit 41: Acos ((ω + α) t + θ
1) Output of oscillator 41i: Bcos (ωt + θ2) where α: angular velocity by Doppler A, B: peak level of each waveform, input of I frequency converter 41c is Acos
((Ω + α) t + θ1) and Bcos (ωt + θ2), and the output is Acos ((ω + α) t + θ1) × Bcos (ωt + θ2) = (AB / 2) {cos ((2ω + α) t + θ1 + θ2) + c
os (αt + θ1−θ2)}, and when the frequency in the 2ω band is cut by the low-pass filter 41e, the output X is given by the following expression (1).

X = (AB / 2) cos (αt + θ1−θ2) (1) Further, the input of the Q frequency converter 41d is Acos ((ω +
α) t + θ1) and Bsin (ωt + θ2), and the output is Acos ((ω + α) t + θ1) × Bsin (ωt + θ2) = (AB / 2) {sin (2ω + α) t + θ1 + θ2) -sin
(Αt + θ1−θ2)}, and when the frequency of 2ω band is cut by the low-pass filter 41f, the output Y becomes as shown in the following expression (2).

Y = − (AB / 2) sin (αt + θ1−θ2) (2) As shown in these equations, in the case of a communication device, a transmitter station and a receiver station, and in the case of a radar device, a radar station. When there is a relative velocity with the moving body, a frequency due to the Doppler effect is generated in the outputs of I and Q. When the Doppler frequency becomes high, there is an influence that the integrator 42 cannot perform integration. Therefore, it becomes necessary to cancel the Doppler frequency.

In the present embodiment, the I and Q detection signals (frequency) are fed back to the oscillator 41i via the loop filter 41h to automatically adjust the frequency so that the Doppler frequency α becomes "0". ing. In the case of this embodiment, the Doppler frequency can be determined by determining the output level of the loop filter 41h. Next, in order to determine the correlation, an integrating circuit 42 is connected to the above I and Q, and the DC component of the detection signal input from the I and Q terminals is integrated for one epoch for determination. A specific example of the integrator circuit 42 is configured as shown in the first embodiment of FIG. 5, in which I and Q are respectively connected to the squarers 42a and 42b,
The square components 42a and 42b square the DC components of I and Q,
The adders 42c add the outputs from the squarers 42a and 42b, and the integrators 42d integrate the outputs for one epoch. In this embodiment, the correlation can be determined without canceling the Doppler frequency. This is because the output of I (see equation (1)) and the output of Q (see equation (2)) are squared by the squarers 42a and 42b and further added by the adder 42c, the output is [( AB / 2) cos (αt + θ1-θ2)] 2 + [- (AB / 2) sin (αt + θ1 -θ2)] 2 = A 2 B 2/2 ... (3) next, because the Doppler frequency component is eliminated .
After the integration for one epoch, the integrator 42d is reset by the reset signal from the signal processing unit 10.

As shown in FIG. 8, the integrator circuit 42 is used as a correlation output circuit 42 (see FIG. 1) without using an integrator, and the output level (correlation value) of the adder is determined to determine the correlation. You can make a decision. When the integrating circuit of FIG. 5 or the correlation output circuit of FIG. 8 is used, the IQ demodulation circuit 41 needs the multiplier 41g and the loop filter 41h for adjusting the frequency as shown in FIG. Instead, it becomes as shown in FIG. FIG. 4 shows a second embodiment of the IQ demodulation circuit 41, and the same components as those in the first embodiment of FIG.

FIG. 6 is a block diagram showing the configuration of the second embodiment of the integrating circuit 42. In the second embodiment,
Integrators 42e and 42f connected to I and Q, respectively
After the DC component is integrated at, squared by the corresponding squarers 42, 42, and further added by the adder 42i. In this embodiment, since the outputs of I and Q are first integrated, there is an effect that the circuit configuration can be easily converted to a digital IC, but unless the Doppler frequency component is eliminated, the integrated value becomes small even if the correlation is obtained. In some cases, it may be difficult to determine the presence or absence of correlation.

The output (integrated value) from the integrating circuit 42 has a low level as shown in FIG. 7 (a) when the correlation is not obtained, and is shown in FIG. The level becomes higher as shown in b). Therefore, the signal processing unit 10
By setting a threshold value of a certain level with respect to the input integration value, the correlation can be determined. This allows
When used as a communication device, the data determination circuit 43 can be connected to I and Q of the IQ demodulation circuit 41 to determine received data and output the data to the signal processing unit 10.

When used as a radar, in addition to distance information, relative velocity information is required. The information required to know the velocity and direction is the Doppler frequency and the positive and negative signs. Therefore, as shown in FIG. 9, the Doppler detection circuit 44 is composed of a level determiner 45 for determining the output levels of I and Q, and a Doppler frequency / code detector 46 for detecting the Doppler frequency and the code from the above determination result. Then, the Doppler frequency and its code are output to the signal processing unit 10.

First, in the determination of the positive and negative signs of the Doppler frequency, as shown in FIG. 10, when one of the I and Q waveforms crosses 0V, the other waveform level is determined. The relative speed ± can be determined. More specifically, both waveforms are as shown in FIG. 10 (a) when the Doppler angular velocity α is negative, and both waveforms are as shown in FIG. 10 (b) when the Doppler angular velocity α is positive. Like

That is, in FIG. 10A, when α <0, the waveform of the output from I is 0 V in the direction from negative to positive.
When crossing, the waveform of the output from Q takes a negative value,
In FIG. 10B, when α> 0, the waveform of the output from Q takes a positive value when the waveform of the output from I crosses 0 V in the direction from negative to positive. Specific circuits and timing charts of the Doppler detection circuit 44 that realizes this detection are shown in FIGS. 11 and 12. In FIG. 11, I and Q from the IQ demodulation circuit 41 are compared with comparators 45a and 45b.
The output of the comparator 45a on the I side is connected to the CLK input of the flip-flop 46a, and the output of the comparator 45b on the Q side is connected to the data input of the flip-flop 46a. Data is held at the rising CLK edge of 46a. As a result, the output of the flip-flop 46a holds the sign of the Q-side waveform when the I-side waveform rises.

The timing charts of FIGS. 12 (a) to 12 (c) show the case where the Doppler frequency shown in FIG. 10 (a) is negative, and the output of the Q side comparator 45b is output when the I side comparator 45a rises. Is always low level. Further, the timing charts of FIGS. 12D to 12F show the case where the Doppler frequency shown in FIG. 10B is positive, and the output of the Q-side comparator 45b is at the rise of the I-side comparator 45a. It will always be high level.

Therefore, in the signal processing unit 10, when the output of the flip-flop 46a is low level, the Doppler frequency shows a negative value, and when the output of the flip-flop 46a is high level, the Doppler frequency is positive. It is possible to detect that the value of is shown. Next, a case where the Doppler frequency is detected in a short time will be described. Conventionally, one cycle of the extracted Doppler frequency is counted to detect the Doppler frequency. However, when the relative speed is small, one cycle is long, which requires a long time to calculate the Doppler frequency. It was Therefore, the present inventor pays attention to the fact that the output waveform of I and the output waveform of Q are always 90 ° out of phase with each other, as shown in FIGS. Waveform and Q output waveform are 0
By counting the V-crossing interval, the Doppler frequency can be calculated in 1/4 of the conventional time.

A concrete circuit and timing chart of the Doppler detection circuit 44 for realizing this are shown in FIGS. 13 and 14. In FIG. 13, I from the IQ demodulation circuit 41,
Q is input to the comparators 45c and 45d to determine whether it is positive or negative, the outputs of the comparators 45c and 45d are input to the exclusive OR gate 45e, and a high level is output to the counter 46b only when there is a difference between the outputs. Configure to output. As a result, the exclusive OR gate 45e
Means that the logical output is inverted every time the output waveforms of I and Q cross 0 V, and the counter 46b detects the Doppler frequency by counting the pulse width of the high level or low level of this output and multiplying it by four. can do.

Therefore, in the signal processor 10, the counter 4
The relative velocity and direction can be calculated from the Doppler code and frequency output from 6b. Therefore, in the present embodiment, the power detection of the despread spectrum can be facilitated by using two kinds of intermediate frequencies. First
The intermediate frequency of 2 needs a certain high frequency to spread / despread, but the second intermediate frequency is much easier to handle than the first intermediate frequency because the despread spectrum is concentrated. When the frequency can be set and the correlation can be obtained by despreading, the power of this second intermediate frequency becomes large, so that the correlation can be determined by detecting this power.

Further, in the present embodiment, when the correlation is detected, the quadrature demodulation circuit performs detection using the same frequency as the second intermediate frequency, the DC components are extracted from I and Q, and they are squared-added. , The output is level-determined or integrated for one epoch to determine the presence or absence of correlation. That is,
In this embodiment, the output level and the integrated value of the adder are high when the correlation is obtained, and the above values are low when the correlation is not obtained. If set, the correlation can be easily determined.

Further, in this embodiment, when there is a relative velocity with the moving body, a beat frequency due to the Doppler effect is generated in the outputs of I and Q, so that one of the I and Q output waveforms is generated. Since the level of the other waveform when 0V crosses is determined, ± of the relative speed can be determined in a short time. Further, if the interval at which both the I and Q waveforms cross 0 V is measured, the Doppler frequency can be detected in a short period of 1/4 cycle.

Furthermore, in the present embodiment, in order to cancel the influence on the data demodulation when used as a communication device, an easy-to-handle low frequency oscillator such as the second intermediate frequency is used, so that the Doppler frequency is canceled. In addition, the frequency of the oscillator of the IQ demodulation circuit can be precisely finely adjusted. In this embodiment, the first and second
Although the spread spectrum is realized by using the intermediate frequency, it can be realized by only the first intermediate frequency. In this case, one kind of intermediate frequency is used, and the first intermediate frequency is set to a high frequency for spreading / despreading. When the correlation is obtained by despreading, the correlation is judged by detecting the power of the first intermediate frequency.

In that case, however, components having a wide frequency band covering the frequency band 0 to the first intermediate frequency (for example, a frequency converter, an I, Q frequency converter, etc.) must be used. Can be expensive,
There is a great effect that the Doppler frequency can be accurately detected using only the first intermediate frequency.

[0041]

As described above, according to claim 1, when one kind of intermediate frequency is used, the first intermediate frequency is set to a high frequency for spreading / despreading, and when a correlation is obtained by despreading. Since the power of the first intermediate frequency is detected and the correlation is determined, it is possible to easily determine whether or not the correlation is determined, quickly detect the Doppler frequency, and perform highly accurate spread spectrum.

In the second aspect, two kinds of intermediate frequencies are used,
The first intermediate frequency is set to a high frequency for spreading / despreading, the second intermediate frequency is set to a frequency lower than the first intermediate frequency, and when the correlation is obtained by despreading, the second intermediate frequency is set.
Since the power of the intermediate frequency is detected to determine the correlation, the presence or absence of the determination of the correlation can be facilitated, the Doppler frequency can be detected quickly, and highly accurate spectrum spreading can be performed.

In the third aspect, detection is performed by the IQ demodulator using the same frequency as the second intermediate frequency, and the DC component is extracted from I and Q. According to the third aspect, the frequency of the IQ demodulator is finely adjusted so as to cancel the Doppler frequency by using the second intermediate frequency that is easy to handle. Therefore, accurate fine adjustment is possible.

According to the fifth aspect, since the DC component is square-added, it is possible to easily determine the presence or absence of the correlation by the output level. According to the sixth aspect, since the DC component is squared and integrated for one epoch, it is possible to easily determine the presence or absence of the correlation. In claim 8, one of the output waveforms from I and Q is 0.
Since the level of the other output waveform when V is crossed is determined to determine whether it is the approaching Doppler frequency or the approaching Doppler frequency, the relative speed ± can be determined in a short time.

In the ninth aspect, the interval at which both output waveforms from I and Q cross 0 V is measured, and the Doppler frequency is 1 /
Since the detection is performed in four cycles, the Doppler frequency can be detected in a short time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a spread spectrum device according to the present invention.

FIG. 2 is a diagram showing spectra of outputs of respective units shown in FIG.

3 is a block diagram showing a configuration of a first embodiment of the orthogonal demodulation circuit shown in FIG.

FIG. 4 is a block diagram showing a configuration of a second embodiment of the quadrature demodulation circuit.

FIG. 5 is a block diagram showing the configuration of the first embodiment of the integrating circuit.

FIG. 6 is a block diagram showing the configuration of a second embodiment of the integrating circuit of the same.

FIG. 7 is a diagram similarly showing an integral waveform of the integrating circuit.

8 is a block diagram showing a configuration of an embodiment of the correlation output circuit shown in FIG.

FIG. 9 is a block diagram showing a configuration of a Doppler detection circuit of the same.

FIG. 10 is a diagram similarly showing an output waveform of the IQ demodulation circuit.

11 is a circuit diagram showing a specific configuration of the Doppler detection circuit (for Doppler code detection) shown in FIG.

12 is a diagram showing a timing chart of the Doppler detection circuit shown in FIG.

13 is a circuit diagram showing a specific configuration of the Doppler detection circuit (for detecting Doppler frequency) shown in FIG.

14 is a diagram showing a timing chart of the Doppler detection circuit shown in FIG.

[Explanation of symbols]

 10 signal processor 20 transmitter 21, 25, 35 oscillator 22 modulator 23 spreader 24, 32, 34 frequency converter 26, 31 antenna 30 receiver 30 despreader 40 correlation detector 41 IQ demodulation circuit 42 integration Circuit / correlation output circuit 43 Data judgment circuit 44 Doppler detection circuit

Claims (9)

[Claims] 1. A pseudo noise signal generation unit for transmission which generates a pseudo noise signal for transmission, a first oscillating unit which oscillates a first intermediate frequency, and the first intermediate frequency by the pseudo noise signal for transmission. A frequency spreading means for spreading the radio frequency band, a radio frequency converting means for converting the spread first intermediate frequency into a radio frequency band and transmitting the radio frequency band; a reception signal in the radio frequency band; First conversion means for converting into the intermediate frequency band of, reception pseudo noise signal generation means for generating the same reception pseudo noise signal as the transmission pseudo noise signal, the reception pseudo noise signal and the reception signal And a de-spreading means for concentrating the spread frequency on the first intermediate frequency when the correlation is obtained. 2. A pseudo noise signal generation means for transmission for generating a pseudo noise signal for transmission, a first oscillating means for oscillating a first intermediate frequency, and the first intermediate frequency by the pseudo noise signal for transmission. A frequency spreading means for spreading the radio frequency band, a radio frequency converting means for converting the spread first intermediate frequency into a radio frequency band and transmitting the radio frequency band; a reception signal in the radio frequency band; First conversion means for converting into the intermediate frequency band of, reception pseudo noise signal generation means for generating the same reception pseudo noise signal as the transmission pseudo noise signal, the reception pseudo noise signal and the reception signal Despreading means for concentrating the spread frequency at the first intermediate frequency when the correlation between the first intermediate frequency and the second intermediate frequency lower than the first intermediate frequency Difference A second oscillating means for oscillating a wave number; and a second converting means for converting the concentrated first intermediate frequency into a second intermediate frequency based on an output from the second oscillating means. A spread spectrum device characterized in that 3. The spread spectrum device comprises:
A third oscillating means that oscillates at the same frequency as the intermediate frequency and is variable in frequency, and divides the output from the third oscillating means into two parts, and shifts the phase of one output by a predetermined angle to output. Phase shifting means, I frequency converting means for frequency-converting by multiplying the second intermediate frequency converted by the frequency converting means and one output of which the phase is not shifted, and I frequency converting means for converting the frequency. 3. The spread spectrum device according to claim 1 or 2, further comprising: a second intermediate frequency and a Q frequency conversion means for converting the frequency by multiplying one of the outputs whose phase has been shifted. 4. The spread spectrum device comprises a multiplication means for multiplying an output of the I frequency conversion means and an output of the Q frequency conversion means, and a level changing means for changing an output level according to an output of the multiplication means. The third oscillating means varies the frequency based on the output level to reduce the Doppler frequency generated at the outputs of the I frequency converting means and the Q frequency converting means. Spread spectrum device. 5. The spread spectrum device comprises a first squaring means for squaring an output of the I frequency converting means, and a second squaring means for squaring an output of the Q frequency converting means, 5. The spread spectrum device according to claim 3, further comprising adding means for adding the outputs of the respective squaring means. 6. The spread spectrum device comprises a first squaring means for squaring an output of the I frequency converting means, and a second squaring means for squaring an output of the Q frequency converting means, 5. The spread spectrum device according to claim 3, further comprising an adding means for adding outputs of the respective squaring means and an integrating means for integrating the added outputs. 7. The spread spectrum device comprises a first integrating means for integrating an output of the I frequency converting means, a second integrating means for integrating an output of the Q frequency converting means, and the first integrating means. It has first squaring means for squaring the output of the means, second squaring means for squaring the output of the second integrating means, and adding means for adding the outputs of the respective squaring means. The spread spectrum device according to claim 3 or 4, characterized in that. 8. The spread spectrum device comprises a judgment means for judging the potential sign of the outputs of the I frequency conversion means and the Q frequency conversion means, and the I frequency conversion means and the Q frequency conversion means based on the judgment result. The spread spectrum device according to claim 3 or 4, further comprising: detection means for detecting a potential sign of the Doppler frequency generated in the output. 9. The spread spectrum device comprises a judgment means for judging the potential sign of the outputs of the I frequency conversion means and the Q frequency conversion means, a calculation means for performing a logical operation of each output, and a calculation result based on the calculation result. 5. The spread spectrum device according to claim 3, further comprising: a detection unit that detects a Doppler frequency generated in the output of the I frequency conversion unit and the Q frequency conversion unit.