JP2591401B2 - Spread spectrum wireless communication equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum radio communication apparatus, and more particularly to a transmitter and a receiver in a spread spectrum (hereinafter, also referred to as "SS") radio communication apparatus in which a carrier frequency and a spread code have a synchronous relationship. S with improved section
The present invention relates to an S wireless communication device.

[0002]

2. Description of the Related Art In recent SS communication, mobile communication using a multiple access method based on SS technology has reached a practical range. As is well known, radio resources are finite, so it is necessary to use frequencies effectively. In that respect, the SS signal is spread over a wide frequency band and its power spectral density becomes very small, so that the influence on other communications is small,
Since mixing in the existing communication frequency band becomes possible, the utility in that aspect is great, and in principle, it can contribute to the improvement of the frequency use efficiency. For this reason, wireless communication by SS is becoming familiar, and it is expected that its application will be expanded to wireless communication for home use in the future, and its future potential and development are greatly expected.

[0003]

2. Description of the Related Art In SS radio communication, synchronization acquisition and synchronization holding in reception are basically necessary, and various synchronization acquisition methods and holding methods have been proposed and put to practical use. Among them, the SS modulation is performed by synchronizing the carrier for the angle modulation (frequency modulation or phase modulation) as the primary modulation and the clock signal for the spread code used for the SS modulation as the secondary modulation. So-called synchronous S
The S modulation and demodulation methods are also known as methods that can somewhat simplify the circuit configuration in reception and demodulation.

[0004] Regarding the prior art of such SS radio communication,
This will be described with reference to the drawings. 1 and 2 show the conventional SS
FIG. 3 is a block diagram of a transmission unit and a reception unit of the wireless communication device, FIG. 3 is a specific block diagram of a signal processing circuit serving as a main part of a DLL (delay lock loop) type synchronization holding circuit,
FIG. 4 is a diagram showing synchronization holding characteristics in a DLL type synchronization holding circuit,
FIG. 5 is a correlation characteristic diagram showing a synchronization acquisition operation of a sliding correlation type.

First, the configuration and operation of the transmission unit will be described with reference to FIG. A signal S (t) such as voice or information is input from an input terminal In1 to a carrier cosω for primary modulation from an oscillator 49.
t are both supplied to the modulator 1 for modulation, where the information S
The primary modulation of (t) is performed, and a modulated wave S (t) cosωt is obtained. Further, the output of the oscillator is supplied to a frequency divider 25, where the clock signal is generated by dividing the frequency to 1 / N ₁ (N ₁ is an arbitrary natural number), and a spreading code generator (P
NG) 48 to generate a spread code P (t). Therefore, the output spreading code P (t) is equal to the carrier cosω
Synchronous relationship with t is maintained. The spread code P (t) is supplied to a multiplier 10 for spread modulation, where SS modulation is performed to generate an SS modulated wave P (t) S (t) cosωt, and a BPF
The signal is output from an output terminal Out1 via a (band filter) 11.

[0006] Such a synchronous SS modulated wave is transmitted as a radio wave to a demodulation unit via a transmission medium such as air via an antenna of another SS radio communication apparatus. The configuration and operation of a demodulation unit of a typical conventional SS wireless communication apparatus will be described with reference to FIG.

The SS-modulated wave is received by an antenna (not shown) of another device and supplied from an input terminal In2 to an AGC (automatic gain control circuit) 20 via a BPF 12, where it is amplified as necessary. Alternatively, after being attenuated, a multiplier 3 for both sliding correlation and despread demodulation, and a DLL-type signal processing circuit for maintaining synchronization (hereinafter simply referred to as “DLL signal processing circuit”)
, Etc.) 36. The multiplier 3 has PNG
(Spreading code generator) The spreading code generated by 47 is also supplied, and the clock signal frequency for this spreading code is
Until the synchronization is acquired, the voltage is set by the VCO (voltage controlled oscillator) 21 slightly higher than that at the time of maintaining the synchronization.
Therefore, the sliding correlation and the despread demodulation are performed in time series.

Here, the operation leading to synchronization acquisition (establishment) will be described. Attenuate unnecessary frequency band components with BPF12 ~
The removed input SS modulated wave P (t) S (t) cosωt is correlated by the multiplier 3 by multiplication with the spreading code P (t) from the spreading code generator 47. This spreading code P (t) is different from the spreading code P (t) generated by the PNG 48 on the receiving side.
Actually, it differs by time τ, and if this is represented by ρ (t), the multiplied output from the multiplier 3 is P (t) * ρ
(t) S (t) cosωt.

The multiplied output is supplied to multipliers 4 and 5, where the reproduced carrier cos (ω) from the VCO 22 is output.
Synchronous detection by multiplication with (t−φ) is performed. Therefore, (1/2) P (t) * ρ (t) * S (t) {cosφ + cos (2ωt−
φ)} is output, and the next stage LPF (low-pass filter)
At 45, the P (t) * ρ (t) S (t) cos (2ωt−φ) / 2 component is removed to become P (t) * ρ (t) S (t) cosφ. If the value of φ is close to 0, the output P (t) * ρ (t) S (t) cosφ of the LPF 45 is about
It is 1/2 level. On the other hand, the reproduction carrier cos (ωt−φ) from the VCO 22 is input to the multiplier 5 by the π / 2 phase shift circuit 2.
3, the phase is shifted by π / 2, and supplied as sin (ωt−φ).

Therefore, the output of the multiplier 5 is (-1/2) P (t) * ρ
(t) * S (t) {sinφ + sin (2ωt−φ)}, and −P (t) * ρ (t) sinφ is output from the LPF 46, but the actual level is close to 0 . The outputs of LPF 45 and LPF 46 are both supplied to a multiplier 6, where the multiplication is performed, and the output is P ² (t) * ρ ² (t) S ² (t) * (-1/2) sin2φ Obtained as an error signal. The error signal is further converted into an error signal of −Ksin2φ by a loop filter 24 that determines a response time constant of the loop, and then supplied to the VCO 22 as a control signal. The carrier recovery circuit 50 composed of such a single-cycle phase locked loop synchronizes the PS with the input carrier.
K demodulation can be performed simultaneously.

After the receiving section of the communication device is turned on, the carrier recovery circuit 50 starts working first, and therefore, after the carrier recovery, the correlation output P obtained from the LPF 45 is obtained.
(t) * ρ (t), that is, the output based on the triangular output characteristic centered at the point t _{0 in} FIG. 5 is supplied to the synchronization determination circuit 34 for synchronization acquisition of the sliding correlation, where the synchronization acquisition point SHL Is detected and supplied to the waveform shaping circuit 35 to obtain a constant DC output from the time of synchronization acquisition. This DC output is supplied to the addition circuit 41, where it is added to the correlation output from the DLL signal processing circuit 36, and then supplied to the VCO 21. The VCO 21 is controlled by the obtained addition output, and the controlled voltage-controlled oscillation output becomes a clock signal for generating a spread code at the time of normal synchronization holding.

Next, the synchronization holding operation will be described. The input SS modulated wave is supplied to the DLL signal processing circuit 36 via the BPF 12. Here, a specific circuit example of the DLL signal processing circuit 36 is shown in FIG. As is clear from FIG. 3, S from the input terminal In3
In the multipliers 7 and 8, the S-modulated wave is supplied with a spreading code (a) {P (t−Δt) earlier in phase than the normal spreading code P (t) and a spreading code (b) supplied from the PNG 47, respectively. ) {P (t + Δt)} which is also Δt slower. Here, Δt is the time corresponding to one bit of the spreading code in the SS system,
That is, since it is one chip time, the output of the multiplier 7 is a PSK modulated wave which is a despread output at the time of normal operation, and is transmitted to the absolute value circuit (or envelope detection circuit) 38 via the narrow band characteristic BPF 13 which can transmit this. Supplied. Similarly, the output of the multiplier 8 is also supplied to the absolute value circuit 39 via the BPF 14.

Accordingly, the output from the absolute value circuit 38 is approximately equal to twice the carrier frequency as P (t) * P (t−Δt).
, And the output of the absolute value circuit 39 is also obtained as a signal obtained by multiplying a component twice as high as the carrier frequency by P (t) * P (t + Δt). Each output signal is supplied to the subtraction circuit 40 and subtracted. The characteristic is an inverse S-shaped correlation characteristic shown in FIG. Note that point (C) is a synchronization holding point. The correlation output thus obtained is output from an output terminal Out3 via a loop filter 37 for processing the correlation output into a control signal, and is added to the output of the output shaping circuit 35 by an addition circuit 41 in FIG. After VCO21
And synchronization is maintained.

[0014]

In the above conventional spread spectrum radio communication apparatus, in the SS modulated wave converted by the up-conversion in the multiplier 3,
By maintaining the carrier frequency of the SS modulated wave and the spreading code in a synchronous relationship, and performing down-conversion with symmetry in modulation and reception by the multipliers 4 and 5 in reception and demodulation, the SS synchronization in demodulation is performed. In addition to the purpose of obtaining the above, it is necessary to reduce the cost of parts by sharing the circuit parts at the time of modulation and demodulation, and to improve the stability while securing the modulation and demodulation performance. In the conventional example, there is no example that adopts such a method, and it is said that there is a thick wall in reducing cost as well as performance aspects such as securing the signal-to-noise ratio during modulation and the signal-to-noise ratio during demodulation. There was a problem.

[0015]

A spread spectrum wireless communication apparatus according to the present invention comprises, on a transmitter side, an angle modulation circuit for angle-modulating an input signal to be modulated, and a local oscillator for outputting a local oscillation signal for modulation. , the frequency of the local oscillation signal and the multiplier that N ₁ multiplied, a first mixer for performing upconversion multiplied by the local oscillation signal N ₁ multiplied to the angle-modulated wave, the angle modulated wave to 1 / N ₁ A first frequency divider for dividing the frequency to obtain a first frequency-divided angle modulated wave, a second mixer for up-conversion by multiplying the output of the frequency divider by the local oscillation signal, and the mixer Output of 1 / N ₂
A _second frequency divider that divides the frequency by (N ₂ ≠ N ₁ ) to obtain a second frequency-divided angle modulated wave, and a spread code generator that generates a spread code for modulation by using the frequency-divided angle modulated wave as a clock signal Vessel and the first
And a third mixer for transmitting a spread spectrum signal by multiplying the mixer output by a spread code.

The receiving section receives a spread spectrum signal, performs despreading demodulation using a demodulation spreading code, and obtains an angle-modulated wave, and has the same frequency as the local oscillation signal for modulation in the transmitting section. a local oscillator for outputting a demodulation local oscillation signal, and a multiplier for the local oscillation signal frequency N ₁ multiplication, a fourth mixer performing downconversion to an output of the despreading demodulation circuit by multiplying the multiplier output the third division of the fourth and angle demodulation circuit of a phase locked loop to the mixer output angle demodulation, peripheral 1 / N ₁ binary voltage controlled oscillator output signal in the angle demodulation circuit passing through the amplitude limiting amplifier A fifth mixer for up-converting the output of the frequency divider by a local oscillation signal for demodulation;
The output of this mixer is 1 / N ₂ and 1 / N ₃ (N ₃ ≠
N _1, N ₂ ), a fourth frequency divider, a fifth frequency divider, a synchronous detection circuit for generating a synchronous detection control signal based on the output of the angle demodulation circuit, and a fourth, fifth frequency divider And a spreading code generator for generating a demodulation spread code using the output of the selection circuit as a clock signal.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a spread spectrum wireless communication apparatus according to the present invention will be described with reference to FIG. FIG.
(A) and (B) are block system diagrams of a transmission unit and a reception unit, respectively, of the spread spectrum wireless communication apparatus 1 of the present invention. One wireless communication device includes both a receiver with such transmission unit, the antenna A _1, A ₂ is not being shared, between use (communication) sometimes naturally other devices, antenna A _1, A
_Since transmission and reception are performed via the communication device ₂ , the following description will be made assuming that the modulation unit and the demodulation unit are mounted on separate communication devices. Note that in FIG. 6, FIGS.
The same components as those of the conventional device shown in FIG.

In the transmitting section shown in FIG. 6A, an information signal S (t) such as an audio signal or data is input to an input terminal.
In1 is supplied to the angle modulation circuit 52 for primary modulation.
Angle modulation generally refers to FM modulation or PM modulation, but in a broad sense FSK (Frequency ShiftKeying) or MSK (Minimum
Shift Keying) and GMSK (Gausian Minimum ShiftKey)
ing). Here, for convenience, FM
The description will be limited to modulation.

In general, an angle modulation circuit directly selects a carrier frequency as a carrier frequency and directly transmits the carrier, or selects a low frequency in advance, performs angle modulation, converts the carrier to a higher frequency by up-conversion, and transmits the carrier. There is. Although the direct transmission method has a simple circuit configuration, the signal-to-noise ratio (S / N ratio) in the modulation circuit tends to be generally worse as the carrier frequency for the frequency shift increases. Thus, the present invention uses a method of selecting a low carrier frequency and up-converting the modulated wave to a target frequency from the viewpoint of securing a necessary SN ratio.

Accordingly, the FM modulation output f (t) is output from the angle modulation circuit 52 and supplied to the up-conversion mixer (multiplier) 9 and the 1 / N ₁ frequency divider 25. On the other hand, it supplies a signal from the local oscillator 49 mixer (multiplier) to 2, and supplied by N ₁ multiplied by N ₁ multiplier 51 to the mixer 9 upconversion FM modulated output f (t) Do. Further, the mixer 2 performs up-conversion of the frequency-divided FM output from the frequency divider 25 using a local oscillation signal.

Here, assuming that the frequency of the FM modulation output is f ₁ that is the same as the intermediate frequency of the receiving unit, the frequency transfer is Δf, and the local oscillation signal is f ₂ , the output of the BPF 15 is (f ₂ × N ₁ ) +
f ₁ = f ₃ , and the frequency transfer is Δf invariant. The output of the BPF 16 is (f ₁ / N ₁ ) + f ₂ and the frequency transfer is Δf / N ₁ . The output of the BPF 16 is amplified by the amplifier 54 and then supplied to the frequency divider 26.
It is 1 / N _2-divided. Therefore, the divided output is {(f
₁ / N ₁ ) + f ₂と な り / N ₂ is a square wave, and the frequency transfer is △ f / (N ₁ * N ₂ ).

The output of the frequency divider 26 is supplied as a clock signal to a spread code generator 48 to generate a spread code P (t). Only the main lobe in the frequency spectrum of the spread code P (t) is transmitted to the spread modulation multiplier 10 via the LPF 42 for removing the side lobe. The up-converted FM modulation output f output to the spreading modulation multiplier 10 via the BPF 15
Since m (t) is supplied, the output of the multiplier 10 is obtained as a spread spectrum modulation output P (t) * fm (t),
5 is appropriately amplified and transmitted from the transmitting antenna A _1.

Next, the receiving section of the apparatus of the present invention will be described with reference to FIG.
This will be described together with (B). Spectrum received by the receiving antenna A ₂ spread signal fm (t) P (t) is supplied to the multiplier 3 for despreading demodulation via the BPF 12. The spread code ρ (t) for synchronization acquisition output from the spread code generator 47 is L
The signal is supplied to the multiplier 3 via the PF 43, where the BPF 1
2 is output and a signal of fm (t) P (t) * ρ (t) is output, and a mixer (multiplier) 3 is output via the BPF 17.
1

The frequency of the oscillation signal of the local oscillator 59 in the receiving section is f ₂ . Since this is the same as the oscillation frequency in the transmission unit, one local oscillator 49 and 59 can be used in the same communication device. The local oscillation signal by N ₁ multiplied by N ₁ multiplier 53 is supplied to the mixer 31, is performed downconversion here. Therefore, the output of the BPF 18 is the intermediate frequency f ₃ − (f ₂ ×
N ₁ ) = f ₁ , and is supplied via an amplitude limiting amplifier 56 to a phase comparator 33 constituting a phase locked loop (PLL) type angle demodulation circuit.

The output of the phase comparator 33 is connected to an error amplifier 57,
The error output (FM) is supplied to the loop filter 24.
Demodulated output), which is supplied to the VCO 22 and
When the LL synchronization is established, the VCO output becomes f ′ (t)
Becomes The VCO output f '(t) is supplied to the phase comparator 33 and also to the 1 / N ₁ divider 27, where it is divided by N ₁ . The output of the frequency divider 27 is the fundamental frequency f ₁ / N ₁
Which is supplied to a mixer 28,
Here, up-conversion is performed by multiplication with a local oscillation signal having a frequency f ₂ from the local oscillator 59, and BP
An output of a frequency of f ₂ + (f ₁ / N ₁ ) is obtained via F19.

This BPF output is simultaneously supplied to the frequency divider 28 and the frequency divider 29 via the amplifier 58.
The frequency is divided to 1 / N ₂ , and the frequency divider 29 divides the frequency to 1 / N ₃ . Therefore, the output of the frequency divider 28 is {f ₂ + (f ₁ / N ₁ )} / N ₂ as the fundamental frequency, and the output of the frequency divider 29 is {f ₂ + (f ₁ / N ₁ ) as the fundamental frequency. ｝ / N ₃ . That is, the frequency of the output of the frequency divider 28 is equal to the frequency of the spread code clock signal on the transmission unit side, and the output frequency of the frequency divider 29 is a frequency slightly different from the frequency of the spread code clock signal of the transmission unit.

The outputs (a) and (b) of the respective frequency dividers are supplied to a selection circuit Sw, and a PLL (phase locked loop) type FM
From the output of the demodulation circuit 61, the level of noise distributed in a frequency band higher than the frequency band of the information S (t) is detected by the synchronization detection circuit 60, and this detection output is converted into a control signal. SS
When the synchronization is established, the noise level supplied to the synchronization detection circuit 60 is low, and when the SS synchronization is not established (at the time of asynchronous operation), the noise level is large.
The control signal is output when the synchronization is asynchronous.

When asynchronous, the output of the frequency divider 29 is supplied to the spread code generator 47 as a clock signal, and the spread code generator 47 outputs a spread code of ρ (t). This spread code ρ (t) is SS
The signal is output until synchronization is established. The synchronization establishment point is mainly determined by the period of the spreading code P (t) and the frequency difference between the spreading code P (t) and the spreading code ρ (t). The control signal becomes low level as soon as the synchronization establishment point is reached in a short time, the output of the frequency divider 28 is supplied to the spread code generator 47 as a clock signal, and the spread code becomes P (t). This is supplied to the despreading multiplier 3.

Thus, the output of the multiplier 3 is fm (t) P
(t) * P (t). As is well known, P (t) is a code that takes +1 and −1, so that P (t) * P (t) becomes almost 1 (DC). The output of the BPF 17 is an output subjected to despread demodulation, that is, an up-converted FM modulated output fm (t). When such SS synchronization is established, the output of the LPF 44 becomes an audio-demodulated audio signal or information signal S (t).
And output from the output terminal Out2.

Here, FIG. 7A shows the F of the angle modulation circuit 52.
FIG. 4B shows the spectrum of the M-modulated output, FIG. 4B shows the up-converted FM-modulated output, and FIG.
Shows the spectrum of the spreading code is a second output, (D) shows the spectrum of the spread spectrum signal outputted from the transmitting antenna A _1.

FIG. 8 shows another example of the configuration of the transmitting section of the apparatus of the present invention. As can be seen by comparing this figure with FIG. 6B, in such a configuration example, the FM from the angle modulation circuit
Instead of modulating the information signal, a spread code (main lobe) from LPF 21, are up-conversion by the mixer 30 by N ₁ the multiplied local oscillation signal. Then, both signals are supplied to the multiplier 10 to perform spread modulation of the FM modulation signal. Accordingly, since the finally output spread spectrum signal and other components are substantially the same as those in FIG. 6B, a detailed description of the operation is omitted.

[0032]

As described above, according to the SS radio communication apparatus of the present invention, while maintaining the synchronization relationship between the spread code and the FM modulation carrier, the transmitting unit previously performs FM modulation of the same frequency as the intermediate frequency of the receiving unit. Since the carrier is obtained and then up-converted and spread modulation is performed with a predetermined carrier frequency set, the carrier frequency is set higher in the FM modulation stage from the FM modulation degree (frequency shift) versus carrier frequency characteristic. Since there is no S / N ratio, a good value can be secured for the S / N ratio, and at the same time, a good value can be secured for securing the stability of the frequency in the FM modulation stage.

In the receiving section, while maintaining the symmetry of the configuration with the transmitting section, while maintaining the SS synchronization between the transmitting section and the receiving section, down-conversion after despread demodulation and conversion to an intermediate frequency, and then FM demodulation by PLL. Therefore, while performing the FM demodulation with a good SN ratio and the FM demodulation with high stability, the used parts can be shared by the transmission unit and the reception unit, and the cost reduction of the apparatus by sharing the used parts is achieved. I have.

Furthermore, despite the fact that a local oscillation signal having no synchronous relationship with the FM modulation carrier frequency is used for the receiving unit,
Since the clock signal for generating the spread code for reception is obtained after canceling the local oscillation signal component, the SS synchronization with the transmission unit is ensured, and the local oscillation frequency for reception is slightly increased due to temperature characteristics and aging characteristics. There is no problem in SS synchronization even if the frequency shifts, frequency division of FM modulation output and PLL for FM demodulation.
The frequency division in the circuit, including the frequency division of the VCO output of the circuit, is devised so that the frequency does not become so high. It has excellent features such as being able to perform laps.

[Brief description of the drawings]

FIG. 1 is a block diagram of a modulator of a conventional typical SS wireless communication apparatus.

FIG. 2 is a block diagram of a demodulation unit of a conventional SS wireless communication apparatus.

FIG. 3 is a specific configuration diagram of a DLL type synchronization maintaining signal processing circuit which is a main part of the conventional device.

FIG. 4 is a characteristic diagram showing a synchronization holding characteristic in a DLL-type synchronization holding signal processing circuit.

FIG. 5 is an explanatory correlation characteristic diagram of a sliding correlation type synchronization acquisition operation.

FIG. 6 is a block diagram showing an embodiment of a spread spectrum wireless communication apparatus according to the present invention.

FIG. 7 is a frequency spectrum diagram for explaining the operation of the device of the present invention.

FIG. 8 is a block diagram showing another configuration example of the demodulation unit in the device of the present invention.

[Explanation of symbols]

2-10 Multiplier 11-19 BPF (Bandpass Filter) 21,22 VCO (Voltage Controlled Oscillator) 24,37 Loop Filter 25-29 Divider 30-32 Mixer 33 Phase Comparator 42-46 LPF (Low-pass Filtering) 47,48 PNG (spreading code generator) 49,59 Local oscillator 51,53 N ₁ multiplier 52 Angle modulation circuit 54-58 Amplifier 60 Synchronization detection circuit 61 PLL type angle demodulation circuit Sw selection circuit

Claims (2)

(57) [Claims] An information signal, such as an audio signal or data, is input to a transmitting unit, which performs angle modulation at a predetermined carrier frequency. and an angle modulation circuit which outputs the angle-modulated wave, first local oscillator and, N ₁ multiplies the frequency of the該局portion oscillation signal to output a modulation local oscillation signal of a frequency different from the said carrier frequency (N
The first mixer ₁ is subjected a first multiplier for any natural number), up-conversion to the angle modulated wave by multiplying the local oscillation signal N ₁ multiplied to the angle modulation wave (high-frequency transformation) A first frequency divider that divides the angle-modulated wave into 1 / N ₁ to obtain a first frequency-divided angle-modulated wave, and multiplies the output of the frequency divider by the local oscillation signal. A second mixer for performing up-conversion, and a second mixer for dividing the output of the second mixer to 1 / N ₂ (N ₂ is an arbitrary natural number different from N ₁ ) to obtain a second frequency-divided angle modulated wave A second frequency divider, a first spread code generator for generating a spread modulation spread code using the second frequency-divided angle modulated wave as a clock signal,
A third mixer that spreads and modulates the angle-modulated wave output from the first mixer by multiplying the spread code by the spread code to transmit a spread-spectrum signal; A despreading demodulation circuit that performs despreading demodulation by a demodulation spreading code to obtain an angle-modulated wave, a second local oscillator that outputs a demodulation local oscillation signal having the same frequency as the modulation local oscillation signal in the transmission unit, The oscillation signal frequency of the second local oscillator is set to N
_A second multiplier for multiplying by _one, a fourth mixer for performing down-conversion (low-band conversion) by multiplying the output of the despread demodulator by the output of the second multiplier, and an amplitude limiting amplifier. A phase-locked loop type angle demodulation circuit for angularly demodulating the output of the fourth mixer passed therethrough, and a third frequency divider for dividing the voltage-controlled oscillator output signal in the angle demodulation circuit to 1 / N _1. A fifth mixer that performs up-conversion by multiplying the output of the third frequency divider by the local oscillation signal for demodulation, and outputs the output of the fifth mixer, respectively.
A fourth and fifth frequency divider for dividing the frequency into / N ₂ and 1 / N ₃ (N ₃ ≠ N _1, N ₂ ), and a control signal for synchronization detection based on the output of the angle demodulation circuit. A synchronization detection circuit, a selection circuit for selectively selecting each of the frequency-divided outputs of the fourth and fifth frequency dividers by the synchronization detection control signal and outputting the clock signal as a clock signal, and a synchronization circuit based on the clock signal. A second spread code generator for generating a demodulation spread code, wherein the synchronization detection control signal is obtained by detecting a level of a noise level higher than an information frequency band in the angle demodulation output signal. A spread-spectrum wireless communication apparatus characterized in that it is configured to be able to operate. 2. A transmitting section, which is a modulating side, and a receiving section, which is a demodulating side. The transmitting section receives an information signal such as an audio signal or data and performs angle modulation at a predetermined carrier frequency. An angle modulation circuit that outputs an angle-modulated wave;
A _first frequency divider that divides the frequency by N1 to obtain a first frequency-divided angle modulated wave, a first local oscillator that outputs a local oscillation signal for modulation having a frequency different from the carrier frequency, the performing the frequency of the oscillation signal N ₁ multiplying (N ₁ is an arbitrary natural number) and a first multiplier that, the up-conversion by multiplying the modulation local oscillation signal to the first division angle-modulated wave 1 mixer and the output of the first mixer is 1 / N
₂ second by dividing into (N ₂ is an arbitrary natural number which is different from the N ₁₎
A second frequency divider for obtaining a frequency-divided angle-modulated wave, and a first frequency divider for generating a spread code using an output of the second frequency divider as a clock signal.
A spread code generator, a second mixer for obtaining a carrier-modulated spread code by multiplying the spread code by the local oscillation signal multiplied by N ₁ , and a second mixer for obtaining the carrier-modulated spread code by the angle modulation. A third mixer for performing spread modulation by multiplying the wave and transmitting a spread spectrum signal, and receiving a spread spectrum signal and performing despread demodulation with a demodulation spread code in a receiving unit to perform angle modulation. despreading circuit for obtaining a wave, the second local oscillator and the oscillation signal frequency of the second local oscillator N ₁ multiplied for outputting a demodulation local oscillation signal of the same frequency as the modulation local oscillation signal in the transmission unit A second multiplier, and a second multiplier for the output of the despreading circuit.
And a phase locked loop type angle demodulation circuit for performing angle conversion of the output of the fourth mixer that has passed through the amplitude limiting amplifier by performing a down conversion (low-band conversion) by multiplying the output of the multiplier. When, by multiplying the third frequency divider which divides the frequency 1 / N ₁ binary voltage controlled oscillator output signal of the angle demodulation in the circuit, the demodulation local oscillation signal to the output of the frequency divider of the third A fifth mixer that performs up-conversion on the basis of the above, and fourth and fifth dividers that divide the output of the fifth mixer to 1 / N ₂ and 1 / N ₃ (N ₃ ≠ N _1, N ₂ ), respectively. A frequency divider; a synchronization detection circuit for generating a synchronization detection control signal based on the output of the angle demodulation circuit; and a divided output of each of the fourth and fifth frequency dividers selected by the synchronization detection control signal. A selection circuit for selectively selecting and outputting as a clock signal; and a selection circuit based on the clock signal. A second spread code generator for generating an adjustment spread code, wherein the control signal for detecting synchronization is obtained by detecting a level of a noise level higher than an information frequency band in the angle demodulation output signal. A spread spectrum wireless communication apparatus characterized by having the above-described configuration.