JPH01223843A - Spread spectrum communication equipment - Google Patents

Abstract

PURPOSE:To simplify the circuit constitution by applying synchronizing detection to a demodulated biphase PSK signal and demodulating and outputting an information signal equivalent to that at modulation. CONSTITUTION:A spread spectrum code signal P(t) is fed to a multiplier 7, where inverse spread with multiplication with an addition output signal P(t)d(t)cosnuc1t from an adder 24 is applied, an undesired frequency component is eliminated by a band pass filter(BPF) 18 and a biphase PSK signal d(t)cosomegac1 is demodulated. A carrier recovery circuit 34 receives the demodulated biphase PSK signal d(t)cosomegac1t, recovers the carrier cosomegac1 and supplies it to a multiplier 8. The multiplier 8 receives the demodulated biphase PSK signal d(t)d(t)cosomegac1t together with the carrier d(t)cosomegac1 to apply synchronizing detection by the multiplication of both the signals, and its output signal is subject to undesired frequency component rejection by a low pass filter(LPF) 37 resulting in causing a demodulated information signal d(t) with high quality and it is outputted from an output terminal Out2. Thus, the circuit constitution is simplified, the cost is reduced and the application to home use appliances is facilitated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a spread spectrum communication device, and particularly relates to a reception (
The present invention relates to a spread spectrum communication device that realizes generation of pseudo-noise codes with a relatively simple circuit configuration in despreading on the demodulation side.

[Technical background]

Spread Spectrum;
The spread spectrum communication method, which performs communication using S S ) communication equipment, was developed in Europe about 50 years ago, and its basic concept was established in the 1950s. In the 1960s, pseudo-noise code generation circuits were created using gigantic transistors, and the early technology was still immature, and the active elements and manufacturing technology that made up these circuits had to be developed. In recent years, the development of high-density IC technology and the reduction in the price of ICs have made it possible to create small and low-cost devices, so the Kagaru communication method is once again attracting attention. . The spread spectrum communication method is a method in which a carrier is firstly modulated with an information signal and then secondarily modulated with a wideband noise-like spreading code to spread the signal over a very wide band. In general, direct spreading (
There are two frequency hopping (FH) systems, a hybrid system, etc., and the system of the present invention relates to a device that implements the former DS system.

Such spread spectrum communication has many features as follows.

■Very high level of confidentiality.

■ Strong against external interference, noise, and intentional interference.

■Can coexist with conventional systems.

■No control station or control channel such as an MCA station is required.

■Address code management is available.

■Since the power density of the DS (Direct Diffusion) method is low, it appears as if no radio waves exist (FIA can be transmitted with low power).

■The number of stations can be increased if the deterioration in call quality is tolerated.

(2) Multiplexing within the same frequency band is possible by changing the pseudo-noise code signal.

These features have been re-recognized, and applications are now progressing not only in the communications field, but in various fields, and are beginning to be applied to consumer equipment.

[Conventional technology]

The basic principle of spread spectrum communication will be explained with reference to FIGS. 6 and 7. FIG. 6 is a basic configuration diagram of a conventional spectrum spreading device using the DS method, and FIG. 7 is a spectrum diagram of each component. As shown in Figure 6, Send! The signal (Fl) as shown in FIG. 7(a), which has been primary modulated by the primary modulation circuit 41 of J (A station), is the spreading code signal (Fss') from the three spreading code generating circuits (FIG. 7(a)). b
)), the signal is secondarily modulated with a spread modulation cycle of 1% 46, and after being amplified, it is output as a transmission signal <Fl, ) from antenna A1. There are no particular restrictions on the type of primary modulation, and frequency modulation (FM) and PSK (Phase 5hi
ft Keying) etc. (in this specification, PS, K
), secondary modulation (
Spread modulation) is generally used as pseudo-noise code (Pseudo-noise code).
No.1se; PSK modulation using PN code).

This PN code must be in the form of random noise and must have a certain period in order to extract the code on the receiver side.

Next, the configuration and functions of the receiving side will be explained. On the receiving side (B station), the F1s' word obtained from the antenna A2 by a predetermined filter and high frequency amplifier is despread in a despreading circuit 47 using a spreading code from a spreading code generating circuit 49. This spreading code generation circuit 49 is synchronized with 83 spreading code signal cycles of station A, and the PN code is also the same (F,). However, the radio waves that enter antenna A2 are not limited to Fls. As shown in Figure 7 (C), radio waves from other SS stations (F2s, F3S,...
) and - radio waves (Fn) from subordination exist. Therefore, by performing despreading with the despreading circuit 'fl@47,
d) Return the desired radio wave F1s as shown to the spectrum shown in FIG.
(see e)), the demodulation circuit 48 demodulates the signal into the original information signal and outputs it. As can be seen from FIG. 4(e), in addition to FlS, the interference wave Fn and a portion of the multi-station SS waves remain in the output signal of the filter 45. The ratio of this residual power to the power of the target signal is called the DN ratio (signal power to interference power ratio), and in order to obtain a large DN ratio, it is advantageous to have as wide a spreading band as possible, and generally speaking The frequency band is approximately 100 to 1000 times the frequency band of the information signal.

The basic principles of spread spectrum communication have been explained above, but next we will discuss 1 and 2 when performing spread spectrum communication.
Next, specific operations in each modulation/demodulation will be theoretically explained. A spread spectrum signal S (t) (FlS in Fig. 6) in spread spectrum communication transmits information data as d
(t)[+1 or -1], spreading code F is set to P(↑)[
+1 or -11, the carrier wave is COSωct and S is expressed by the following equation.

S (t) = d (t) P (t) cosωct
−・・−−(1) (However, ωC = 2πfc) This spread spectrum signal S (t) is generated by generating a clock signal for a spread code from the incoming spread spectrum signal during reception (demodulation), and further during transmission. is multiplied (also referred to as correlation or despreading) with the incoming spread spectrum signal 5(t), resulting in d(t) cosωat 2 It is converted into a phase PSK signal.

7/ to\, Regenerated carrier wave COSωct (actually COSωc
Synchronous detection is performed by multiplication with tl, which results in d
(t) (CO3ωct) 2 = d
(t)(1+CO32ω(Ht)/2 is obtained and the carrier wave component 2ωct is removed by a filter to demodulate the information data d(t).

[Problem to be solved by the invention]

In such spread spectrum communication devices, despreading on the receiving side is the most important, but it is not easy to generate the spreading codes necessary to perform this, and currently it is difficult to generate the spreading codes necessary for this, and currently it is difficult to generate the spreading codes necessary for this, and currently it is difficult to generate the spreading codes required for this, so currently it is difficult to generate the spreading codes necessary for this, Despreading methods and despreading methods using a synchronized loop using a matched filter and a multiplier are commonly used. Despreading using these configurations all have complicated circuit configurations, and there are also problems with adjustment and GoS1~, and these problems need to be resolved before deployment to consumer equipment. be.

[Means to solve the problem]

The communication device of the present invention includes, on the modulation side, means for inputting an information signal and a first carrier wave and generating a two-phase PSK signal by multiplication, and a means for inputting a clock signal and generating a spreading code signal based on this. means for generating a control signal in synchronization with the spread code signal by inputting a clock signal and frequency-dividing the clock signal;
and a means for obtaining a modulated wave signal by inputting the carrier wave and multiplying the modulated wave signal.

The demodulation side includes a means for performing spreading by multiplying the added signal obtained by adding the modulated wave signal and the two-phase PSK signal by a spreading code signal to generate and output a spread spectrum signal, and on the demodulation side, 2-phase PS by inputting spread spectrum signal
means for separating the signal component into a signal component represented by the product of the K signal and the spreading code signal, and a signal component represented by the product of the modulated wave signal and the spreading code signal; means for separating and reproducing control signals by inputting and signal processing signal components;

means for configuring a clock signal based on the reproduced control signal to generate a spreading code signal synchronized with the spreading code signal on the modulation side; means for obtaining a demodulated two-phase PSK signal by inputting a signal component represented by the product of code signals and performing despreading by multiplication of both signals; The above-mentioned problem is solved by comprising a means for demodulating and outputting an equivalent information signal.

〔Example〕

Since the spread spectrum communication device of the present invention is configured as described above and performs communication, a clock recovery circuit has been an essential component in despreading.

This eliminates the need for a synchronization pull-in circuit, a synchronization holding circuit, etc., which are constituted by a loop.Hereinafter, one embodiment of the device of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the spread spectrum communication device of the present invention, in which (A) shows the modulation section (transmission side) 1.
0. FIG. 2B shows the demodulator (receiving side) 20. In this figure, illustration of a part of the structure such as the antenna is omitted.

The modulation section 10 includes three multipliers 3 to 5. Arithmetic circuit (adder) 23. Spreading code generation circuit (PNG) 22.

LPF (low pass filter) 21. Perimeter 13. Blue frequency divider 11. Monostable multivibrator (hereinafter also simply referred to as monomulti J) 12. and two BPFs (bandpass filters)
14, 15, etc., and these are connected and configured as shown in Figure 1 (^). Furthermore, the demodulator 20 has three BPs.
F16-18, two delay circuits (DL) 26.28
; Adder 24. Subtractor 25. Shaping circuit 29, doubling circuit 30. N multiplier circuit 31. Monomulti 32. Spreading code generation circuit 33, carrier recovery circuit 34. LPF37. and two multipliers 7, 8, etc., which are connected as shown in FIG. 1(B). Note that the delay circuit 26, the adder 24. and the subtracter 25 constitute a comb-shaped filter 27 having two types of characteristics, and its frequency characteristic is the second one.
These are shown as addition characteristics and subtraction characteristics in Figures (A) and (B), respectively. Below are the specific functions and operations.
This will be explained with reference to the spectra of FIGS. 3 and 4.

First, when transmitting, the modulating section 10 supplies the carrier wave signal COSωC+j to the multiplier 3 from the input terminal In+. On the other hand, the information signal d(t)(
In this case, it means data) is supplied to the multiplier 3 via the LPF 21, and primary modulation (in this case, 2-phase PSK modulation) is performed by multiplication with the carrier wave signal COSωC+t. ), the primary modulation signal (2) as shown in (a)
A modulated signal) d(t)cosωC+j is generated on the phase ps and output to the adder 23. Further, the input terminal In 2 supplies the carrier wave signal COSωC2t to the multiplier 4, and the input terminal In 4 supplies the clock signal C(t) to the subfrequency divider 11 and the spreading code signal circuit i22. ,
The subfrequency divider 11 divides the clock signal C(t) into 1/H, and then supplies the output D V (D) to the monomulti 12 and the sufficient frequency divider 13.The sufficient frequency divider 13 divides the clock signal C(t) into 1/H. (t) is further divided into 1/4, and the BPF 14 transmits only the fundamental wave component to obtain the control signal COSωt. That is, the control signal COSωt is obtained from the control signal 1 to the roll signal COS.
The frequency of ωt is set to 174N of the clock signal C(t). The control signal COSωt is supplied to the multiplier 4 and multiplied by the carrier wave signal COSωCzt to produce a multiplied output signal C having a waveform as shown in 0) in FIG. 3(B).
OSωC2jCOSωt is obtained. This multiplication output signal COSωc2tcosct>t is outputted to the adder 23 by 2
By adding the phase PSK modulation signal d (t) cosωC+t, the addition output signal d (i) CO3ωc1t
+COSωQ2tcO3ωt is obtained and output to the multiplier 5.

On the other hand, the spreading code generation circuit 22 uses the clock signal C(t)
A spreading code signal p (B is generated based on the following. Spreading code signal p (B is a random signal that is repeated at a certain period, and the period is such that the blue frequency division output DV (1) is supplied to the monomulti 12. This is based on the period of the reset signal R(t) obtained by signal processing the reset signal R(t), the above clock signal c(H), and the spreading code signal p Usually, pseudo-noise codes are often created, so they are sometimes called "pseudo-noise codes J." In this embodiment, the control 1 to roll signals COSωt
The period for one cycle is four times that of the spreading code signal p(H).The spreading code signal p(t) is supplied to the multiplier 5, where the above-mentioned addition output signal d(i)CO3(t)
C1t + CO3ωc2t; Spreading is performed by multiplication with CO3ωt, and as a result, the spread spectrum signal P
(t) (d (j) CO3ct+ C1t +CO8
(1) c2tCO8ωt) (hereinafter also referred to as '5N(i)J) is obtained. BPF15 is a spread spectrum signal S+
It passes only through the main lobe of (i) (see Figure 4).

The signal is transmitted, converted into a signal having a spectrum as shown in FIG. 3(C), and supplied to the output terminal prediction 1.

Here, the principle of spectrum spread etc. will be explained. Angular frequencies ωc1 and ω shown in Figure 3 (^) and (B), respectively
The frequency interval with c2 is given by (2F×T O)-', where To is the 1-bit time length of the clock signal C(1), and F is the number of bits in 1 frame of the spreading code signal P(t). The interval will be Also, in the frequency spectrum of the spread spectrum signal shown in Fig. 3(C), sideband +S
Frequency interval between a1 and +Sa2 or +Sb) and +sb
The frequency interval with 2 is the interval given by (FXTO)-1, and the sideband waves +Sal ~ +san, Sal
~Sad, sideband +sb, ~+Sbn, 5
t) 1 to -3bn are arranged alternately at equal intervals. Note that the solid line (portion n) in Figure 4 ((a) and (b)
) indicates the main lobe of the spread spectrum signal.

Next, the functions and operations of the demodulator 2 will be explained with reference to FIG. 1(B) and FIG. 3. A spread spectrum signal SM (FC) such as FIG. 3 entered the input terminal In 5
Noise components other than the spread spectrum signal are removed by the BPF16, and the signals are sent to the delay circuit 26 and the adder 24.j). and the positive input terminal of the subtracter 25 at the same time. Furthermore, since the output of the delay circuit 26 is configured to be supplied to the negative input terminals of the adder 24 and the subtracter 25, these delay circuits 2
6. The adder 24 and the subtractor 25 form a comb-shaped filter 27 having addition characteristics and subtraction characteristics (see FIGS. 2(A) and 2(B), respectively). Now, delay circuit 2
Assuming that the delay time at 6 is T (-1/F), in the case of addition, as shown in Figure 2 (A), 1/T, 2/T
.

3/T,...,N/]'' (N is a natural number), the gain becomes 2 (@), and at each intermediate frequency, the output becomes 0, creating a steep dip. In the opposite case, as shown in the same figure (B), 1/T, 2/T.

Valley (gain is 0) at the frequency of 3/T,..., N/T
The gain is doubled at each intermediate frequency. Therefore, by setting the delay time to T=FXTQ,
If the frequency of the peaks or valleys of the comb-shaped filter 27 is matched to the sideband frequency of the spread spectrum signal, the first spread signal 5z(j) in the spread spectrum signal S)1(t)
(−P (t) d [j) CO3ωc, t ) and the second spread signal S 2 (t) (= P (t) cosω
This makes it possible to detect them separately from C2 and CO3ωt). As a result, the output signal of the adder 24 becomes S+(t) (see 37th fD), and the output signal of the subtracter 25 becomes 5
2(j) (see (E) in the same figure). Note that the principle of the separation operation of the comb-shaped filter 27 will be described later, but here, the principle of the separation operation of the comb-shaped filter 27 will be explained.
The expression of the delay amount is omitted for convenience of explanation.

The addition output signal S+(i) from the adder 24 is supplied to the multiplier 7, and the subtraction output signal 52(t) from the subtracter 25 is supplied to the delay circuit 28 and the multiplier 6.

The delay circuit 28 outputs the subtracted output signal 52(t) for a predetermined time τ.
The signal is delayed by a certain amount and then supplied to the multiplier 6. This delay time τ corresponds to one frame of the spread code signal P(t) (π/2 of the control signal CO3ωt). Therefore, the output signal of the delay circuit 28 is 52(j-T)=P(t-y
r/2ω) cosωc2(t-π/2ω)x cosω
(t-π/2ω) (2), and this delayed output signal is supplied to the multiplier 6, where it is multiplied by the subtracted signal 52 (1). .

Through this operation, the spreading code signal P (t) becomes a direct current,
A multiplication output signal is obtained. This multiplication output signal is BP
The control signal component cos2ωt is supplied to Fl7, where the control signal component cos2ωt is passed through detection 2, and the waveform is shaped by two shaping circuits before being supplied to the doubling circuit 30. As a result, a double output equivalent to the divided output Dv(t) of the sub frequency divider 11 of the modulation section 10 is obtained from the double multiplier circuit 30. This doubled output is supplied to an N-multiplying circuit 31 and a monomulti 32, and as a result, a clock signal C(t) equivalent to that at the time of modulation is regenerated from the N-multiplying circuit 31, and a clock signal C(t) equivalent to that at the time of modulation is regenerated from the monomultiplier 32. A reset signal R(t) equivalent to the output of the multi 12 is reproduced. Further, the spreading code generating circuit 33 is connected to the spreading code generating circuit 22 (and the sixth spreading code generating circuit 22) on the transmission side.
It has the same configuration as the conventional circuit 39, 49) shown in the figure, and therefore, by inputting the clock signal C(t) and reset signal R(t), the spreading code signal p(B is equivalent to You can get a good signal.

The spread code signal P(1) thus obtained is supplied to the multiplier 7, where the addition output signal P from the adder 24 is sent to the multiplier 7.
(t) d (j) CO3ωct Despreading is performed by multiplication with t, and unnecessary frequency components are further removed in BPFl 8, resulting in a two-phase PSK signal d (t) cosωCt
t (see FIG. 3(A)) is demodulated. The carrier wave regeneration circuit 34 receives this demodulated two-phase PSK signal d(t)cosωC
tt, carrier wave COSωC is obtained by the principle described later.
1t and supplies it to the multiplier 8. The multiplier 8 demodulates 2
Phase P S K (@ d (t) cos ω Ctj is input together with carrier wave C03 (dClt) and synchronous detection is performed by multiplying both signals, and the output signal is demodulated with unnecessary frequency components removed by LPF37. Good quality information signal d
(t) and is output from the output terminal 2.

−18= Here, regarding a specific configuration example of the carrier wave regeneration circuit 34,
This will be explained with reference to FIG. As shown in this figure, the carrier regeneration circuit 34 includes a multiplier 9. BPFI9, phase-locked loop (
PLL) 35 and a frequency divider 36, which are connected as shown in the figure. That is, this is a double carrier wave recovery circuit. 2-phase P not supplied from BPF18
The SK signal d(t)CO3ωC1t is squared by the multiplier 13.

Such a two-phase PSK signal has two carrier waves of 0° and 180°.
Since the frequency is modulated by two phases, multiplier 9 modulates the frequency by two phases.
When doubled, it is converted into a continuous phase carrier wave of twice the frequency. In other words, in the two-phase PSK signal, the binary signal d(t) is converted to DC by the square operation, and the carrier wave COSωc1t is converted to cos
2ωC+t. The output of the multiplier 9 is used as the BP of the next stage.
After removing unnecessary frequency components at F19, PLL35
supply to. This PLL35 is composed of a multiplier (or phase comparator), LPF (or loop filter), CO, etc. Here, unnecessary noise components in the input signal are removed and the frequency of 21@ with constant amplitude is A carrier wave is obtained.

This carrier wave is subjected to signal processing by the frequency divider 36, and a reproduced carrier wave COSωc1t is output.

Next, the separation and detection operation of the spread spectrum signal S M (j) (the operating principle of the comb-shaped filter 32, etc.) will be explained. The spread spectrum signal SM output from the delay circuit 26 in FIG. 1(B) is SM (i-T) −P
(t-T) (d (tzu)cosωC+ (t-T)+
CO3ω02 ft-T)cosω(t-T))--
--(3). Here, as a precondition, P (t
) and the delay time T are equal, and cosωc1t is p
Continuous wave that repeats at the same phase and level with a period of (t), COS
If ωc2t is a continuous wave that repeats at the same level and in opposite phase with a period of P (t), then SM(t-T) is 3M(tzu) -P (tHd (i-T)CO3ωC
1t-COSωC2tCO3ω(t-T))...
......(4). Therefore, the addition output SM(
t) しSM(t-T)(-=S+(j)) is S+(i)-3M(j)-1-SM(t-T)-(d
(t)+d(t-T))P(t)cosωc,
t+(COδωt−cosω(tzu))P(t)co
sωC2t −(5). On the other hand, the subtraction output S 2 (
i) is 52(t)-8)1(i) SMft-T)
−(cosω ft−T))P (t
) to 03ωC2t+ I d (t)-d (t-T)
)P (t) cosωCIt (6). Note that (cosωt-cosωft-T)) in the fifth equation
P(j)CO3ωC2t and I d (t)-a of the sixth equation
(t-■))p (t)COSωc1t will be a very small value if the 1-bit time length of information data d(1) and the half-cycle time length of control signal COSωt are sufficiently long compared to the delay time T, and it can be approximated by It can be omitted. Therefore, both equations can be expressed as follows.

S+(t)→ (d (t)+d (t-T))P (
t) cosωC+ t...value 7) S2(t) (
cosω t ten cosω ft-T)) x p (
t)cosω02 t・・・・・・・・・・・・
(8) Next, the operation of the spreading code generation process will be specifically explained according to the configuration shown in FIG. 1(B). The delay circuit 28 provides a delay time T. Since this delay time T corresponds to the time of one frame of the spreading code Pft), the output signal S2(j)X of the multiplier 6
S2(j-T) is S2(i)X S2(1-T
) =CO32ωt(p(t)cosωC2'I)2--
−”・(9), removed by BPF17, cos2
An output signal ωt is obtained. After this output signal is shaped into a binary signal by the shaping circuit 29, the next-stage doubling circuit 30
When the signal is multiplied by 2 to become a signal equivalent to Dv(i)) and further multiplied by N by the N multiplier circuit 31, the output is
The signal becomes a signal equivalent to the clock signal C(t) supplied from the input terminal F14 of the modulation section 10), and is supplied to the spreading code generation circuit 33. Furthermore, the monomulti 32 receives the frequency-divided signal D supplied to the monomulti 12 of the modulation section 10.
A monomulti 12 is supplied with a signal equivalent to v(t).
The same operation will be performed as in MonoMulti 3.
2 and the clock signal from the N multiplier circuit 31, the spreading code generating circuit 33 operates similarly to the spreading code generating circuit 22 on the modulating section 10 side to generate an equivalent spreading code. That's what you get.

Finally, the despreading operation will be specifically explained.

The multiplier 7 is supplied with the addition signal S+(i) from the adder 24 and the spreading code p (B) from the spreading code generation circuit 33, and generates a despread output signal S, (t)xp (B
is obtained. That is, 5t (t)X P ft) - (d (t) Sat d (t-T))
lt--...=...(10). During this signal, (P
(t))2 can be considered as direct current, so it is removed by BPF18, and + d m+ct(t-T)) C03(1
) The signal is demodulated into two-phase ps called C1t.

The carrier wave regeneration port 1134 inputs this demodulated two-phase PSK signal, regenerates the carrier wave COSωC+t according to the above-mentioned principle, and supplies it to the multiplier 8, where the carrier wave and the demodulated two-phase PSK signal are
By performing synchronous detection by multiplying the SK signal d [t) cos ωC + j and further removing unnecessary frequency components in the LPF 37, a high-quality information signal d ('t) is demodulated and output from the output terminal 2. That's why.

〔effect〕

Since the spread spectrum communication device of the present invention is configured as described above, it has the following excellent features.

■Despreading using the AFC control loop, delay lock loop, and multiplier, which were essential components in conventional equipment, specifically includes a clock regeneration circuit, a spreading code generation circuit, a synchronization pull-in circuit consisting of a loop, and a synchronization maintenance circuit. Most of the circuits other than the spreading code generation circuit are no longer required, and the simplification of the circuit configuration reduces costs and makes it easier to deploy in consumer equipment.

■Some circuits that require advanced technology, such as synchronization pull-in circuits and synchronization holding circuits, are no longer required, which eliminates the disadvantage of the long synchronization pull-in time in conventional devices.
Freed from problems such as out-of-sync problems,
It can contribute to stabilizing the operation of spread spectrum communication equipment.

[Brief explanation of the drawing]

Figure 1 (^L) (B) is a block diagram of the modulation section and demodulation section of an embodiment of the spread spectrum communication device according to the present invention, and Figures 2 (A) and (B) are the frequencies of the comb-shaped filter. Characteristic diagrams, Figures 3 (8) to (E) are frequency spectrum diagrams for explaining the operation of each component of the device of the present invention, Figure 4 is a spread spectrum signal waveform diagram, and Figure 5 is a circuit block diagram of a carrier regeneration circuit. , FIG. 6 is a basic block configuration diagram of a conventional spread spectrum communication device, and FIG. 7 is a spectrum diagram for explaining the operation of each component of the conventional device. 3 to 9... Multiplier, 10... Modulation Part, 11... Sufficient frequency generator, 12.32... Monostable multivibrator,
13... Sufficient frequency filter, 14-19... BPF (band filter), 20... Demodulator, 21.37... LPF
(low-pass filter), 22.33... Spreading code generation circuit, 23, 24... Arithmetic circuit (adder), 25... Subtractor, 26° 28... Delay circuit, 27. ...Comb-shaped filter, 29... Shaping circuit, 30... Double multiplier circuit,
31...N multiplier circuit, 34...carrier regeneration circuit, 3
5... PLL, 36... Sufficient frequency generator, In+, In2
...carrier signal input terminal, In s...information signal input terminal, In a...clock signal input terminal, tn
5...Spread spectrum signal input terminal, shells 1 to 2...
・Output terminal 9

Claims (1)

[Claims] On the modulation side, a means for inputting the information signal and the first carrier wave and generating a two-phase PSK signal by multiplication, a means for inputting a clock signal and generating a spreading code signal based on this;
means for inputting the clock signal and frequency-dividing it to generate a control signal in synchronization with the spread code signal; inputting the control signal and a second carrier wave and generating a modulated wave signal by multiplication; and means for generating and outputting a spread spectrum signal by performing spreading by multiplying the added signal obtained by adding the modulated wave signal and the two-phase PSK signal by the spreading code signal. The demodulation side receives the spread spectrum signal and converts it into a signal component represented by the product of the two-phase PSK signal and the spread code signal, and a signal component represented by the product of the modulation wave signal and the spread code signal. means for separating and reproducing a control signal by inputting and signal processing a signal component represented by the product of the separated modulated wave signal and the spreading code signal; means for configuring a clock signal to generate a spreading code signal synchronized with the spreading code signal on the modulating side; and a product of the generated spreading code signal, the separated and detected two-phase PSK signal, and the spreading code signal. Means for obtaining a demodulated two-phase PSK signal by inputting a signal component represented by and performing despreading by multiplication of both signals, and obtaining information equivalent to that at the time of modulation by synchronously detecting the demodulated two-phase PSK signal. 1. A spread spectrum communication device comprising: means for demodulating and outputting a signal.