JPS63238731A - Transmitting/receiving system - Google Patents

Abstract

PURPOSE:To omit the necessity of synchronism by allowing a receiving side to square a transmitting signal obtained by synthesizing a false noise signal including data to be transmitted and to demodulate the squared signal through a filter means. CONSTITUTION:When it is defined that the code of data to be transmitted is D(t), a false noise code of a false noise code generator 1 is P(t) and a reference frequency signal of an oscillator 3 is cosomegat, the output of a mixer 4 becomes P(t).D(t)cosomegat. On the other hand, the output of a mixer 6 is -P(t)sinomegat, so that the output of an adder 7 becomes P(t).D(t)cosomegat -P(t)sinomegat and is transmitted through a band pass filter 8. The receiving side squares said transmitting signal by a mixer and receives the squared signal as 1 -D(t)sin2omegat. When the receiving signal is passed through the band pass filter, -D(t)sinomegat can be obtained. Since the filtered signal does not include the code P(t), the signal can be demodulated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a transmitting/receiving system that performs communication using a spread spectrum method.

BACKGROUND OF THE INVENTION In recent years, the spread spectrum method, which spreads the transmission spectrum and shares a wide frequency band, has been attracting attention.

This spread spectrum method modulates the spectrum by applying a type of code (this code is called a pseudo-noise code), and demodulates only the signal with that code, distinguishing it from other signals. , by changing the sign, more communication channels can be set. In addition, methods of use that take advantage of its features compared to other conventional communication methods, such as being resistant to noise and interference and having excellent privacy, are being considered.

Problems to be Solved by the Invention Now, the direct spread spectrum method is known as one of the methods mentioned above, but according to this method, the receiving device side is synchronized with the pseudo-noise code used for modulation on the transmitting device side. It is necessary to perform processing such as delayed lock tracking and tau dither tracking.

Therefore, the receiving device not only has a complicated configuration, but also requires time to synchronize in advance.In view of the above-mentioned drawbacks of the prior art, the present invention provides a new transmitting/receiving system that does not require time to synchronize. This is what we provide.

Means for Solving the Problems The present invention comprises a pseudo-noise code generating means for generating a pseudo-noise code, a first mixer for modulating transmission data with the pseudo-noise code of the pseudo-noise code generating means, and a reference frequency signal. oscillation means for generating, a phase shift means for shifting the phase of the reference frequency signal of the oscillation means by 90 degrees, and a second mixer for converting the frequency of the output of the first mixer by one of the output of the oscillation means or the phase shift means. a third mixer for converting the frequency of the pseudo noise code of the pseudo noise code generating means by the other of the output of the oscillation means or the transfer means;
A transmitting device comprising an adding means for adding the outputs of the second and third mixers, and an arithmetic means for multiplying the transmitted signal by the transmitting signal of the transmitting device, and an output of the arithmetic means. The above-mentioned object is achieved by a receiving device provided with a f-technical means for passing only signals related to the transmission data.

According to the above configuration, the present invention modulates the data to be transmitted with the pseudo-noise code that is the output of the pseudo-noise code generating means, and then
Frequency conversion is performed using a reference frequency signal by an oscillation means and a 90° phase shift means, and a pseudo-noise signal containing data to be transmitted is synthesized with a cosine component and a sine component, and the signal is transmitted from a transmitter. On the other hand, by taking advantage of the transmitted signal and passing it through the F technique, the receiving device can obtain the necessary signal and demodulate it, and there is no need for synchronization on the receiving device side.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of main parts of a transmitting device of a transmitting/receiving system according to an embodiment of the present invention.

In FIG. 1, ■ is a pseudo-noise code generator that generates a pseudo-noise code; 2 is a mixer that mixes the data to be transmitted with the output of the pseudo-noise code generator 1; 3 is an oscillator that generates a reference frequency signal; 4 is a mixer that converts the frequency of the baseband output of mixer 2 with the output of oscillator 3; 5 is a 90° phase shifter that shifts the phase of the reference frequency signal output from oscillator 3 by 90°; 6 is a pseudo noise code generator 1; A mixer that converts the frequency of the output using the output of the phase shifter 5, an adder 7 that adds the outputs of mixers 4 and 6, and a band bus 8 that passes only the frequency band necessary for the output of the adder 7.・It is a filter. It is assumed that mixer 2.4.6 is a double-balanced mixer and performs two-phase phase modulation.

The operation of the above configuration will be explained below.

First, the data to be transmitted is mixed with the pseudo noise code sent from the pseudo noise code generator 1 in the mixer 2. The modulated signal is further sent to the mixer 4 and frequency-converted by the reference frequency signal sent from the oscillator 3. For example, if the reference frequency signal of the oscillator 3 is
Then, the output of mixer 4 is P(t)・■【)・cD
%)t.

(However, P([) is the pseudo-noise code of pseudo-noise code oscillator 1, and P(t)=+1 or -1. Also, D
(t) is data to be sent, and it is assumed that D(t)=+1 or -1. ) On the other hand, the oscillator 30 reference frequency signal bunch ωt is also sent to the 90° shifter 5, and after phase conversion to -smωt, it is sent to the mixer 6.
The pseudo-noise code sent from the pseudo-noise code generator 1 is frequency-converted to output a signal -P(t)·sinωt.

Next, adder 7 adds the outputs of mixers 4 and 6,
P (t) ・D(t) ・Houseωt −P(t)s&+ in the band pass filter 8
ωt ...-(1) is sent out.

Then, in the band pass filter 8, the mixer 2, .
After removing high frequency components, DC components, noise, etc. generated in steps 1 and 6, the signal is transmitted via the antenna as a transmission signal.
Alternatively, the data is transmitted to the receiving device side by wire. Alternatively, the transmitting device of this embodiment modulates the data to be transmitted with a pseudo noise code that is the output of the pseudo noise code generator 1, and then performs frequency conversion using the reference frequency by the oscillator 3 and the 90' phase shifter 5 to generate a pseudo noise code. A cosine component containing a noise code and data and a sine component having only a pseudo-noise code can be combined and transmitted.

In this embodiment, the reference frequency signal of the oscillator 3 is sent to the mixer 4 and to the mixer 6 via the 90' phase shifter 5.
It goes without saying that it may be provided between the oscillator 3 and the mixer 4 instead of between the oscillator 3 and the mixer 4.

Next, the configuration of a receiving device of a transmitting/receiving system according to an embodiment of the present invention will be explained.

FIG. 2 shows a block diagram of main parts of a receiving device of a transmitting/receiving system 2 in an embodiment of the present invention.

In Fig. 2', 21 is a mixer that multiplies the received signals sent from both lines 21a and 21b, and 22 is a band pass filter that passes only the component containing the transmission data from the output of mixer 21. It is.

The operation of the above configuration will be explained below.

First, the signal of the first formula sent out from the transmitter shown in FIG.
tjcos'ωt +P (tfsin"ωt2 P(
t)・D(t)・sinωt−tuftωt−−(2
). Here, since pH = ±1 and D(t) = ±1, p+J = nttf = 1, and the second equation is 1- D (t) sin 2 GJ t
An output of (3) is sent to the band pass filter 22.

In the band pass filter 22, −D(t
Lsin2 ωt −=・−(
4) only. This signal has a center frequency of 2ω/2π and is a two-phase modulated signal using the transmission data source), and does not include the pseudo-noise code P (t) used for spectrum spreading. Since the fourth equation is a two-phase phase modulation signal, in order to demodulate the transmission data D(1) from this, a well-known means for demodulating a two-phase phased signal (for example, Costas loop demodulation or bit delay detection). Therefore, the transmission data D(t) modulated by the transmitter shown in FIG. 1 has been demodulated by the receiver shown in FIG.

In the explanation based on the embodiment shown in FIG. 2, it was explained that the device shown in FIG. 2 directly receives data from the band pass filter 8 shown in FIG. 1, but if necessary, only the necessary band can be received via a filter. However, after being amplified by a preamplifier, the signal may be converted to an intermediate frequency by a local oscillator, and the received signal may be amplified by the intermediate amplifier. In such a case, ω shown in the second, third, and fourth equations is the intermediate frequency ω.
', but the band pass filter 2 in Figure 2
The signal obtained from 2 is still −D(t)sin2ω′t
and does not cause any problems. Although the mixer 21 is used to implement the reception Nobuhide, other arithmetic circuits may be used.

Effects of the Invention As described above, the present invention modulates the data to be transmitted with a pseudo-noise code that is the output of the pseudo-noise code generation means, then performs frequency conversion using a reference frequency signal by the oscillation means, and transforms the data into a cosine component. , the same pseudo-noise code above is 90°
The frequency signal produced by the phase shifting means is combined with the frequency-converted sine component and transmitted from the transmitting device, while the receiving device takes the transmitted signal and passes it through the filtering means to obtain the necessary signal. Demodulation is now possible, and there is no need for the receiving device to synchronize with the pseudo-noise code on the transmitting side, such as conventional delay lock tracking or tau dither tracking, and it is also possible to transmit only the pseudo-noise code. Moreover, it is less susceptible to the influence of the group delay characteristics of the transmission path, and its effects are significant.

[Brief explanation of drawings]

FIG. 1 is a block diagram of main parts of a transmitter of a transmitter/receiver system according to an embodiment of the present invention, and FIG. 2 is a reception diagram of a transmitter/receiver system according to an embodiment of the present invention that receives a transmission signal from the transmitter of FIG. 1. It is a main part 'y' lock connection diagram of the device. 1...pseudo noise code generator, 2. 4. 6.21・
... mixer, 3... oscillator, 5... 90' phase shifter,
7... Adder, 8.22... Hunt pass filter. Name of agent: Patent attorney Satoshi Nakao (one male)
1′

Claims (2)

[Claims] (1) a pseudo-noise code generation means for generating a pseudo-noise code; a first mixer for modulating transmission data with the pseudo-noise code of the pseudo-noise code generation means; an oscillation means for generating a reference frequency signal; a phase shifting means for shifting the phase of a reference frequency signal of the means by 90 degrees; a second mixer for frequency converting the output of the first mixer by either the output of the oscillating means or the phase shifting means; and the oscillating means or a transmitter comprising: a third mixer for converting the frequency of the pseudo noise code of the pseudo noise code generating means by the other output of the phase shifting means; and an adding means for adding the outputs of the second and third mixers; , for the transmission signal of this transmitter,
A transmitting/receiving system comprising a receiving device comprising a calculating means for multiplying the transmitted signal, and a filtering means for passing only signals related to the transmitted data from the output of the calculating means. (2) The transmitting/receiving system according to claim 1, wherein the calculation means is a mixer.