JPS63131631A - Transmission equipment - Google Patents

Abstract

PURPOSE:To eliminate the need for a synchronizing time by synthesizing a cosine component modulated by a data signal and then modulated by a sent data after an output of an oscillation means is modulated by a pseudo noise and a sine component being the modulation result of the signal phase-shifted from a reference frequency signal at a 90 deg. phase shift means while being modulated by the same pseudo noise. CONSTITUTION:A pseudo noise code generated from a pseudo noise code generator 1 and a reference frequency signal generated by an oscillator 2 are mixed by a mixer 3 and the output of the mixer 3 is multiplied with the data to be sent by a mixer 4. On the other hand, the reference frequency signal cosomegat of the oscillator 2 is also sent to a 90 deg. phase shifter 5, subject to phase conversion with sinomegat, multiplied with the pseudo noise code sent from the pseudo noise code generator 1 by a mixer 6 to output a signal of sin(omegat+P(t)). An adder 7 adds the outputs or the mixers 4, 6 to give a signal of cos(omegat+P (t)+phi(t))+sin(omegat+P(t)) to a bandpass filter 8. The band pass filter 8 eliminates harmonics, DC component or noise and gives the result to a receiver.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a transmitting device 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 giving it 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 above-mentioned methods. According to this method, the receiver side is synchronized with the pseudo noise code used for modulation on the transmitter side. Generally, processing such as delayed lock tracking or tau/dither tracking is performed. (For example, 5pre
ad Spectrum SystemR,O,Dix
on, John Wiley & 5ons I
nc, 19 Ryo 6) Therefore, the configuration of the receiving device not only becomes complicated, but also requires time to establish synchronization in advance.

SUMMARY OF THE INVENTION In view of the drawbacks of the prior art described above, the present invention provides a new transmitting device and its receiving device that do not require time for synchronization.

Means for Solving the Problems The present invention comprises a pseudo-noise code generating means for generating a pseudo-noise code, an oscillating means for generating a reference frequency signal, and a phase shifter for shifting the phase of the reference frequency signal of the oscillating means by 90'. a first mixer for multiplying one of the outputs of the oscillation means or the phase shift means by a pseudo noise code generated by the pseudo noise generation means; a second mixer that multiplies the output of the first mixer by the pseudo noise code of the noise code generating means; a third mixer that multiplies the output of the first mixer by the data to be transmitted; and the output of the second mixer and the third mixer. and an adding means for adding the outputs of.

According to the above configuration, the present invention modulates the output of the oscillation means for generating the reference frequency signal with the pseudo noise that is the output of the pseudo noise code generation means, and then further modulates the cosine component modulated with the data signal with the transmission data. The modulated signal is synthesized with a sine component obtained by modulating a signal obtained by phase-shifting the reference frequency signal by 90° phase shifting means with the same pseudo noise as described above, and the synthesized signal is transmitted from the transmitting device.

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 transmitter according to an embodiment of the present invention.

In FIG. 1, 1 is a pseudo-noise code generator that generates a pseudo-noise code, 2 is an oscillator that generates a reference frequency signal, and 3 is an oscillator that generates a reference frequency signal.
is a mixer 4 that multiplies the pseudo noise code generated by the pseudo noise code generator 1 and the reference frequency signal generated by the oscillator 2;
is a mixer that multiplies the output of mixer 3 by the data to be transmitted, 5 is a 90° phase shifter that shifts the phase of the reference frequency signal generated by oscillator 2 by eO', and 6 is the output of pseudo noise generator 1 and a shifter. 7 is a mixer that multiplies the output of phaser 5; 7 is an adder that adds the outputs of mixer 4 and mixer 6; 8 is a band pass filter that passes only the frequency band necessary for the output of adder 7. . It is assumed that mixer 3.4.6 is a double-balanced mixer and performs two-phase modulation.

The operation of the above configuration will be explained below.

First, the pseudo noise code generated by the pseudo noise code generator 1 and the reference frequency signal generated by the oscillator 2 are multiplied by the mixer 3. The output of mixer 3 is further.

It is multiplied by the data to be transmitted by mixer 4.

For example, the reference frequency signal of the oscillator 2 is set to cosωt (where t is time and ω is the angular frequency from several tens of MHz to several hundreds of MHz).
z), the output of mixer 3 is am(ωt+P(t
) ), the output of mixer 4 is 0(ωt + P(t)+
φ(t)). (However, P (t) is the phase of the pseudo-noise code of the pseudo-noise code generator 1, P(t) = O', or 18o0. Also, φ(1) is the phase of the data to be sent, φ( t) = d or 180'.

) On the other hand, the oscillator 20 reference frequency signal ωt is also sent to the so' phase shifter 6, and after phase conversion with ωt, it is multiplied by the pseudo noise code sent from the pseudo noise code generator 1 in the mixer 6, The signal ωt+p(t) is output.

Next, adder 7 adds the outputs of mixers 4 and 6,
Band pass filter 8 has crs (ωt + P(t)+φ(t)) + s
A signal of in (ωt + P(t))−·(1) is sent out.

Then, in band pass filter 8, mixer 3.4
, 6, and removes high frequency components, DC components, noise, etc., and transmits the signal as a transmission signal via an antenna or by wire to the receiving device.

As described above, the transmitting device of this embodiment combines the pseudo-noise code generated by the pseudo-noise code generator 1, the cosine component containing the data to be transmitted, and the sine component containing only the same pseudo-noise, and transmits the synthesized signal. I can do it.

In this embodiment, the reference frequency signal of the oscillator 2 is sent to the mixer 3 and to the mixer 6 via the 90' phase shifter 6.
It goes without saying that it may be provided between the oscillator 2 and the mixer 3 instead of between the oscillator 2 and the mixer 3.

Next, the configuration of a receiving device relative to a transmitting device in an embodiment of the present invention will be explained.

FIG. 2 is a block diagram showing a main part of a receiving device with respect to a transmitting device in an embodiment of the present invention.

In Fig. 2, 21 is a 90° phase shifter that shifts the phase of the received signal by 90°, 22 is a mixer that multiplies the received signal by the output of the 90'' phase shifter 21, and 23 is a filter that removes the high frequency components of the mixer 22. It is a low pass filter that

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. 1 is sent to the eo' phase shifter 21 as a received signal, and is expressed as sin (ωt + P(t)+φ(t)) + c
A phase transformation of Qs (ωt + P(t) ) −(2) is performed.

Next, the mixer 22 multiplies the first equation and the second equation, and the mixer 22 outputs 1.

, (s+n 2 (ωt + P(t)+φ(t)
) + 5in2(ωt +P(t) ') )+■φ
(1) ・・・・・・・・・・・・(
3) is sent to the low pass filter 23. The low pass filter 23 removes the high frequency component (several 10 MH2 to several 100 MH2) including ωt in the third equation, that is, removes the first term of the third equation, and removes the second term
Only φ(t) (several 10 Ktlz band) is allowed to pass. This ■φ(1) is determined by ■φ(1) as the transmission data φ in Figure 1.
(1), therefore, the transmission data φ(1) modulated by the transmitter of FIG. 1 has been demodulated by the receiver of FIG. 2.

In the explanation based on the embodiment shown in FIG. 2, it was explained that the device shown in FIG. 2 directly receives signals from the band pass filter 8 shown in FIG. 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 equation is the intermediate frequency ω'. Although ω shown in the third equation is converted to ω-ω', the signal obtained from the low-pass filter 23 in FIG. 2 is still ■φ(1), which does not cause any problem.

Effects of the Invention As described above, the present invention combines a cosine component modulated with a pseudo-noise code and data to be transmitted, and a sine component modulated only with the same pseudo-noise code, and transmits the synthesized signal from a transmitting device. , the receiving device shifts the phase of the transmitted signal by 90 degrees, multiplies it again, and passes it through the door wave means, thereby making it possible to obtain the necessary signal and demodulating it. There is no need to synchronize using means such as tracking, and the effect is great. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of main parts of a transmitting device in an embodiment of the present invention, and FIG. 2 is a block diagram of main parts of a receiving device in an embodiment of the present invention that receives a transmission signal from the transmitting device of FIG. It is a diagram. 1... Pseudo noise code generator, 2... Oscillator, 3.4
．． 6.22...Mixer, 6.21...90' phase shifter, 7... Adder, 8°°° hand pass filter,
23...Low pass filter. Name of agent: Patent attorney Satoshi Nakao, and one other person.

Claims (1)

[Claims] pseudo-noise code generation means for generating a pseudo-noise code; oscillation means for generating a reference frequency signal; phase-shifting means for shifting the phase of the reference frequency signal of the oscillation means by 90°; a first mixer that multiplies one of the outputs by a pseudo-noise code generated by the pseudo-noise generating means; and a first mixer that multiplies the other output of the oscillation means or the phase-shifting means by the pseudo-noise code of the pseudo-noise code generating means. a third mixer that multiplies the output of the first mixer by the data to be transmitted; and an adding means that adds the output of the second mixer and the output of the third mixer. Transmitting device.