JPH08307397A - Ss type radio equipment - Google Patents

Abstract

PURPOSE: To prevent the occurrence of interference when an SS type radio equipment is applied to a weak radio wave type half-duplex radio equipment. CONSTITUTION: A transmitting part (modulating part) includes an input terminal 1, an information modulation part 2, a multiplying circuit 3, a double balance mixer 4, an RF amplifier 8 and an information-modulated wave subjected to high frequency conversion by the circuit 3 is subjected to spread modulation by the mixer 4. A receiving part (demodulating part) includes an RF amplifier 12 for inputting a received signal inputted through an antenna 11, a BPF 10 and a switch 9, a double balance mixer 13, an RF stage BPF 14, a mixer 15, a local oscillator 16, an IF stage BPF 17, an IF amplifier 18, an information demodulation circuit 19, frequency dividers 20, 21, a frequency conversion circuit 22, an output terminal 23. A received SS modulated wave from the amplifier 12 is subjected to inverse-spread demodulation by the mixer 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a SS system radio apparatus in which a spread spectrum (SS) technique of a dual modulation system for performing information modulation and spread modulation is applied to a half-duplex type radio apparatus, and particularly to the SS system and weak radio waves. System SS wireless device.

[0002]

2. Description of the Related Art In recent years, the SS communication system has been increasingly applied to the consumer field along with the release of radio waves. For example 2.4G
It becomes possible to operate the SS data transmission system in the Hz band, and the application to the SS system by the weak radio wave becomes possible with the revision of the electric field strength measurement method for the wide band modulated wave of the weak radio wave. The needs for application to the are also increasing.

FIG. 3 shows a conventional 2.4 GHz band, half-duplex SS system radio apparatus. The transmission data such as information input through the input terminal 51 is transmitted to the information modulation circuit 52.
Information is modulated by PSK (Phase Shift Keying), F (Frequency) SK, etc., and then through the bandpass filter (BPF) 53, the double balance mixer 5
4 and the information modulated wave of the intermediate frequency is spread-modulated.

In the double balance mixer 54, the BPF5
3 output signal to spread code (pseudo noise: PN) generator (P
NG) 55 is spread-modulated by multiplying by a spread code, and the signal spread-modulated in this way is BPF.
56, an amplifier 57, and a switch 58 to a double balance mixer 59, which performs frequency conversion using the local oscillation frequency generated by a local oscillator 60 by the double balance mixer 59, and a frequency of 2.4 GHz band (RF). Is converted to. The output of the double balance mixer 59 is transmitted as an SS wave from the antenna 65 via the switch 61, the amplifier 62, the switch 63, and the BPF 64.

On the other hand, the S received via the antenna 65
The S wave is BPF 64, switch 63, AGC amplifier 6
6, applied to the double balance mixer 59 via the switch 61. This double balance mixer 59 is used for both transmission and reception by utilizing the fact that it can be used bidirectionally by the diode bridge method, and converts the received SS wave into an intermediate frequency. The output of the double balance mixer 59 is applied to the SAW (surface acoustic wave) convolver 73 via the switch 58, the AGC amplifier 67, the BPF 68, and the frequency divider 69, and is subjected to despread demodulation.

The SAW convolver 73 is a device exclusively for the SS system that obtains the correlation output of the SS wave while performing the convolutional integration, and is used in the SS system wireless modem and the like. Here, the frequency-divided local oscillation signal obtained by the local oscillator 60 and the frequency divider 70 and the spread code generated by the spread code generator 55 are multiplied by the double balance mixer 71 to obtain a spread modulated wave, and the spread modulated wave is transmitted via the BPF 72. SA
The spread code pattern of the spread modulated wave applied to the W convolver 73 is the opposite (symmetric) to that of the received SS wave. That is, in this conventional example, despread demodulation is performed in the intermediate frequency stage.

The output of the SAW convolver 73 is the AGC amplifier 74, BPF 75, convolution detection circuit 7
7. The data is supplied to the baseband demodulation circuit 78, demodulated into reception data, and output via the output terminal 79. Also,
The gains of the AGC amplifiers 66, 67 and 74 are the AGC circuit 7
Controlled by 6.

[0008]

However, in the above-mentioned conventional SS system radio apparatus, since despreading modulation is performed at the intermediate frequency stage, when it is applied to the SS system radio apparatus of weak radio waves, there is a problem that it receives interference. is there. That is, since the transmission output of the radio device of a weak radio wave is about 0.045 microwatts, which is extremely low as apparent from the power difference of 68 dB as compared with 260 mW of the SS radio device in the 2.4 GHz band, There is a problem in that a weak radio wave radio device gives interference of approximately the same level to a desired signal level corresponding to the received electric field strength due to interference interference radiated from a logic circuit or the like. Therefore, 2.4GH
Even if the interference level is not a problem in the z-band SS wireless device, it is difficult to put it into practical use in a weak radio device, and it is necessary to take a large-scale shielding means to avoid such interference. There is a problem that becomes.

The SS type wireless device applicable to the 2.4 GHz band has a high cost due to high cost of high frequency components and is not widely used. On the other hand, a general weak radio wave radio device has been put to practical use within a limited transmission distance range, but the SS system and the weak radio wave radio device have a wide range of applications and a frequency of 322 MH.
Since it is less than z, it is possible to use inexpensive circuit components due to the low frequency, and it is expected to be applied in various fields. However, the cost of circuit components for SS is still high, so it is possible to reduce weak radio waves. The application of is not widespread even though it has high expectations. Here, as a method of reducing the cost, a method of integrating the SS circuit unit (IC) is generally used, but most of the commercially available SS system integrated circuits are 2.4G.
Developed for the Hz band, the frequency is 322M
It cannot be applied to weak radio waves below Hz.

In view of the above-mentioned conventional problems, it is an object of the present invention to provide an SS system wireless device capable of preventing interference when the SS system is applied to a weak radio system half-duplex wireless device. .

[0011]

In order to achieve the above object, the present invention performs spread modulation and despread demodulation in a high frequency stage, and switches the output of the modulation unit and the input of the demodulation unit in the high frequency stage by a switch. I have to.

That is, according to the present invention, a switch means for switching between transmission and reception in a high-frequency stage including an antenna, an information modulation means for modulating information of transmission information, and an information-modulated wave modulated by the information modulation means are made high-frequency. And a spreading modulation means for spreading-modulating the high-frequency information-modulated wave from the high-frequency processing means and transmitting it through the switch means, and a received wave input through the switch means at a high-frequency stage. There is provided an SS radio apparatus including a despread demodulation means for despread demodulation and an information demodulation means for converting a high frequency information modulated wave demodulated by the despread demodulation means into an intermediate frequency and demodulating the information.

Further, according to the present invention, the spread modulation and the despread demodulation are performed in the high frequency stage, and the despread demodulation clock for generating the receive spread code is generated based on the received signal.

That is, according to the present invention, switch means for switching between transmission and reception at a high frequency stage including an antenna,
The information modulating means for modulating the information on the transmission information, the high frequency converting means for frequency-multiplying the information modulating wave modulated by the information modulating means by N times and increasing the frequency, and the information modulating wave modulated by the information modulating means. Spreading modulation clock generation means for dividing and generating spreading modulation clock, spreading code generation means for generating transmission spreading code based on the spreading modulation clock, and high frequency information modulation from the high frequency conversion means Spreading modulation means for spreading-modulating a wave by the spreading code for transmission and transmitting it through the switch means, and despreading demodulation means for despreading and demodulating the received wave input through the switch means by the spreading code for reception. A frequency conversion means for converting a high frequency information modulated wave demodulated by the despreading demodulation means into an intermediate frequency by a local oscillation signal; and the frequency conversion means. Information demodulating means for demodulating the information-modulated wave of the intermediate frequency, and the first modulated-wave having the synchronous waveform shaped to the information-modulated wave of the intermediate frequency is divided into 1 / N and the divided information-modulated wave is output. Frequency dividing means, second frequency dividing means for dividing the local oscillation signal into 1 / N, the first and second
An information-modulated wave having the same frequency as the information-modulated wave modulated by the information-modulating means is reproduced by the signal divided by the frequency-dividing means, and a despreading demodulation clock is generated based on the reproduced information-information modulated wave. Then, there is provided an SS radio apparatus having the spreading code generating means and the despreading demodulation clock generating means for generating the reception spreading code based on the despreading demodulation clock.

[0015]

According to the present invention, since the spread modulation and the despread demodulation are performed in the high frequency stage and the output of the modulation unit and the input of the demodulation unit in the high frequency stage are switched by the switch, the SS modulated wave of the wide band in the high frequency stage is narrow band. Since the information modulated wave is converted to the information modulated wave, the narrow band information modulated wave is less likely to be interfered with even if the logic circuit is present. Therefore, when the SS method is applied to the weak radio method half-duplex wireless device, the interference occurs. Can be prevented.

Further, according to the present invention, since the spread modulation and the despread demodulation are performed in the high frequency stage and the despread demodulation clock for generating the spread code for reception is generated based on the received signal, the logic circuit exists. Even if it does, the narrowband information modulated waves are less likely to be interfered with, and therefore, when the SS system is applied to the weak radio system half-duplex wireless device, the interference can be prevented.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the SS system radio apparatus according to the present invention, and FIG. 2 is a block diagram showing an SS synchronization acquisition circuit applied to the SS system radio apparatus of FIG.

In FIG. 1, the transmitting section (modulating section) has an input terminal 1, an information modulating section 2, a multiplying circuit 3, a double balance mixer 4 and an RF amplifier 8, and the information modulating wave converted to a high frequency by the multiplying circuit 3. Is spread-modulated by the double balance mixer 4. The output signal of the RF amplifier 8 is the switch 9 and the RF stage BPF 10 common to the transmitter and the receiver (demodulator).
Also, the switch 5, the frequency divider 6, and the spread code generator (PNG) 7 are common to the transmitter and the receiver.

The receiving section (demodulation section) includes an antenna 11 and a BPF.
RF amplifier 12, double balance mixer 13, R to which the received signal input via switch 10 and switch 9 is input
The F-stage BPF 14, the mixer 15, the local oscillator 16, the IF-stage BPF 17, the IF amplifier 18, the information demodulation circuit 19, the frequency dividers 20 and 21, the frequency conversion circuit 22, and the output terminal 23 are provided, and the reception SS from the RF amplifier 12 is provided. The modulated wave is despread and demodulated by the double balance mixer 13.

In such a configuration, at the time of transmission, an information signal d (t) such as data is applied to the information modulation circuit 2 via the input terminal 1 and information is modulated by the information modulation circuit 2. Here, assuming that the information modulation is FSK for convenience, the FSK modulated wave F (t) modulated by the information modulation circuit 2 is used.
Consists of frequency fm and modulation factor m. This FSK modulated wave F
(T) is supplied to the N1 multiplication circuit (“× N1” in the figure) 3 and converted into a high frequency. Frequency multiplication number N1 in this case
Is determined by the relationship between the frequency fm of the information modulated wave F (t) and the actual radio carrier frequency fc, the high-frequency information modulated wave N1 × fm is fc, and the modulation degree thereof is N1 × m.

The output fc of the N1 multiplication circuit is supplied to the transmission side double balance mixer 4, multiplied by the spread code p (t) for modulation generated by the spread code generator 7, spread-modulated, and SS modulated. The wave s (t) is output. Here, in the spread code generator 7, the information modulated wave F (t) obtained from the information modulation circuit 2 via the transmission terminal T of the switch 5 is used as a clock signal c (t) by a frequency divider (“1/1” in the figure). N2 ") 6
Since the frequency of the clock signal c (t) is fm / N2, the spread code p (t) for modulation and the information modulated wave F (t) are obtained. It is in a synchronous relationship. The SS modulated wave s (t) that has been spread and modulated by the double balance mixer 4 is transmitted via the amplifier 8, the switch 9 (transmission terminal T), the BPF 10 and the antenna 11.

On the other hand, at the time of reception, the SS modulated wave received via the antenna 11 has noise n in the transmitted wave s (t).
BPF 10 and switch 9 with (t) added
The signal is supplied to the reception side double balance mixer 13 via the (reception terminal R) and the amplifier 12, and is subjected to despread demodulation at the high frequency stage. In the receiving side double balance mixer 13, the received SS modulated wave [s (t) + n (t)] is despread and demodulated by the spreading code p ′ (t) for demodulation generated by the spreading code generator 7 and output F ′. (T) + n ′ (t) is supplied to the frequency conversion mixer 15 via the BPF 14 and converted to an intermediate frequency. Here, when the local oscillation frequency applied from the local oscillator 16 to the frequency conversion mixer 15 is f0, the intermediate frequency fi obtained via the frequency conversion mixer 15 and the BPF 17 is N1 × fm-f0.

This intermediate frequency fi is applied to the information demodulation circuit 19 through the amplifier 18, and the FSK modulated wave F '(t) is applied.
Demodulation of + n '(t) is performed and output through the output terminal 23. Here, the information demodulation circuit 19 performs demodulation by the phase locked loop (PLL), and the output of the voltage controlled oscillator (VCO) in the PLL is the input FSK modulated wave F ′ (t) +.
It is synchronized with n '(t). Moreover, since the PLL circuit also functions as a tracking filter that follows the input signal, the output of the VCO is the input FSK modulated wave F ′ (t) + n ′.
An FSK modulated wave having a better signal S / noise N ratio than that of (t) can be obtained.

The output of this VCO is divided into 1 / N1 by a frequency divider ("1 / N1" in the figure) 21, and this frequency-divided output [fm- (f0 / N1)] is converted into a frequency conversion circuit 22.
Is applied to In the frequency conversion circuit 22, the local oscillation frequency f0 from the local oscillator 16 is also divided by a frequency divider (“1/1” in the figure).
N1 ") signal f0 / N divided into 1 / N1 by 20
1 is applied, and the frequency conversion circuit 22 obtains a reproduced information modulated wave of frequency fm by f0 / N1 + fm- (f0 / N1).

That is, the frequency f of this reproduced information modulated wave
m is equal to the frequency fm of the information modulated wave F (t) at the time of modulation. Then, when this reproduced information modulated wave is applied to the spread code generator 7 via the switch 5 (reception terminal R) and the frequency divider 6, when the spread code p '(t) for demodulation is obtained, p'
(T) is equal to the spreading code p (t) for modulation.

Next, the SS synchronization acquisition circuit applied to the radio apparatus of FIG. 1 will be described with reference to FIG. here,
When the SS synchronization is performed, the process that is first performed is the capture of the SS synchronization. This circuit is different from the circuit shown in FIG. 1 in that the clock synchronization acquisition oscillator 31, the synchronization acquisition circuit 32, the synchronization detection circuit 33, and the amplitude limiter. An amplifier 37, an LPF 38 and a switch 39 are added, and the switch 39 is the frequency divider 6 shown in FIG.
And the spread code generator 7.

The information demodulation circuit 19 is composed of a PLL circuit and includes a phase comparator (φ) 34 and a loop filter (L).
F) 35 and VCO 36, and the output (error signal) of the phase comparator 34 is a band-limited amplifier 37 as a demodulation signal,
It is output through the LPF 38 and the synchronization detection circuit 3
3 and the output of the VCO 36 is applied to the frequency divider 21 shown in FIG. Since other configurations are the same as those shown in FIG. 1, the same reference numerals are given and description thereof is omitted.

In FIG. 2, the frequency of the synchronous acquisition oscillator 31 is set to fm / N2 + Δf, and this is set to the spread code generation circuit 7
When it is supplied as a clock signal of the signal through the switch 39, a frequency error Δf from the original clock signal fm / N2 is generated.
It's just off. Therefore, in the double balance mixer 13 of the demodulation section, the SS synchronization is broken, and the despreading output occurs in which the correlation points are burst-shaped. Therefore, by utilizing the characteristic that the error noise (demodulation noise) of the PLL circuit 19 is minimum at the correlation point and maximum at the non-correlation point, the synchronization detection circuit 3 detects the correlation point for SS synchronization.
It is detected by 3.

Then, when the synchronization detection circuit 33 detects the correlation point, the synchronization acquisition circuit 32 switches the switch 3
When 9 is switched from the synchronous acquisition oscillator 31 to the output of the frequency divider 6 and applied as the clock signal of the spread code circuit 7,
The SS synchronization is completed, and thereafter, the SS synchronization is maintained according to the synchronization tracking of the PLL circuit 19. Also, the phase comparator 3
The output of 4 (error signal) is used as a demodulation signal by the amplifiers 37, L
When it is output via the PF 38, the AGC circuit is not necessary because the amplifier 37 is of the amplitude limiting type.

Therefore, according to the present invention, claim 1,
In addition to those described in 2, the following SS wireless device can be obtained. The information demodulating means is composed of a PLL circuit including a phase comparator, a low-pass filter and a voltage controlled oscillator, and the phase difference between the intermediate frequency modulated wave obtained by the frequency converting means and the oscillation frequency of the voltage controlled oscillator is 3. The SS system according to claim 1, wherein the SS synchronization is captured by detecting the correlation point of the SS synchronization based on the phase difference detected by the phase comparator and further detected by the phase comparator. Wireless device.

[0031]

As described above, according to the present invention, the spreading modulation and the despreading demodulation are performed in the high frequency stage, and the output of the modulating unit and the input of the demodulating unit in the high frequency stage are switched by the switch. Since the wideband SS modulated wave is converted into the narrowband information modulated wave, the narrowband information modulated wave is less likely to be interfered with even in the presence of the logic circuit. It is possible to prevent interference when applied to a heavy wireless device.

Further, in the present invention, since the spread modulation and the despread demodulation are performed in the high frequency stage and the despread demodulation clock for generating the spread code for reception is generated based on the received signal, the logic circuit exists. Even if it does, the narrowband information modulated waves are less likely to be interfered with, and therefore, when the SS system is applied to the weak radio system half-duplex wireless device, the interference can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an SS wireless device according to the present invention.

FIG. 2 is a block diagram showing an SS synchronization acquisition circuit applied to the SS radio apparatus of FIG.

FIG. 3 is a block diagram showing a conventional 2.4 GHz band, half-duplex SS system wireless device.

[Explanation of symbols]

2 information modulation section (information modulation means) 3 multiplication circuit (high frequency conversion means) 4 double balance mixer (constitutes spreading modulation means together with switch 5, frequency divider 6 and spreading code generation circuit 7) 5 switch 9 switch (transmission / reception) Changeover switch 6 Frequency divider 7 Spread code generation circuit 11 Antenna 13 Double balance mixer (switch 5, frequency divider 6,
Spreading code generation circuit 7, local oscillator 16, frequency divider 20, 2
1 and the frequency conversion circuit 22 constitute despreading demodulation means) 15 mixer (constitutes intermediate frequency conversion means together with local oscillator 16 and BPF 17) 16 local oscillator 19 information demodulation circuit (information demodulation means) 22 frequency conversion circuit

Claims (2)

[Claims] 1. A switch means for switching between transmission and reception at a high frequency stage including an antenna, information modulating means for modulating information of transmission information, and high frequency converting means for increasing the frequency of an information modulated wave modulated by the information modulating means. A spread modulation unit that spread-modulates the high-frequency information-modulated wave from the high-frequency conversion unit and transmits the modulated wave through the switch unit; and an inverse spread-demodulation unit that reverse-spread demodulates the received wave input through the switch unit. An SS system radio apparatus comprising: spread demodulation means; and information demodulation means for converting the high frequency information modulated wave demodulated by the despread demodulation means into an intermediate frequency and demodulating the information. 2. A switching means for switching between transmission and reception at a high frequency stage including an antenna, information modulating means for modulating information of transmission information, and an information modulated wave modulated by the information modulating means is frequency-multiplied by N times, High-frequency increasing means for increasing the frequency, spread-modulation clock generating means for dividing the information-modulated wave modulated by the information-modulating means to generate a spread-modulation clock, and transmitting spread on the basis of the spread-modulation clock. Spread code generating means for generating a code, spread modulation means for spread-modulating the high frequency information modulated wave from the high frequency converting means by the spread code for transmission, and transmitting through the switch means, and through the switch means Despreading demodulation means for despreading demodulating the received wave input by a receiving spreading code, and high-frequency information modulation demodulated by the despreading demodulation means To an intermediate frequency by a local oscillation signal, an information demodulating means for demodulating the information modulated wave of the intermediate frequency from the frequency converting means, and a modulated wave of which the synchronous waveform is shaped to the information modulated wave of the intermediate frequency. To 1 / N and outputs a frequency-divided information modulated wave; second frequency dividing means to divide the local oscillation signal into 1 / N; An information modulated wave having a frequency equal to that of the information modulated wave modulated by the information modulating means is reproduced by the signal divided by the frequency dividing means of 2, and a despreading demodulation clock is generated based on this reproduced information modulated wave. Then, the spread-spectrum-code generating means includes a despread-demodulation-clock generating means for generating the reception spread-code based on the despread-demodulation clock, and an SS radio apparatus.