JPS63296424A - Spread spectrum communication equipment - Google Patents

Abstract

PURPOSE:To contrive attainment of light weight and miniaturization of the titled equipment by selecting any of plural series of pseudo random numbers in response to a transmission data and applying frequency deviation modulation to a signal according to the selected data, thereby transmitting the result and using the transmitter as a nonlinear amplifier. CONSTITUTION:The transmission side is provided with plural pseudo random number generating means 3a-3d generating a pseudo random number of different orthogonal code series, a selector switch 21 selecting any of outputs of the pseudo random number generating means in response to the sent data 2, and a frequency deviation modulation means 22 applying frequency deviation modulation to the output to attain frequency spread. The receiver side is provided with plural pseudo random number generating means 23a-23d, plural frequency deviation modulation means 24a-24d applying frequency deviation modulation to the output, plural mixture means 25a-25d mixing the output signal of the modulation means with a reception signal to apply inverse split to the reception signal, and a discriminating means 27 selecting a signal having high correlativity among the outputs of the mixing means and demodulating it. Thus, the spread spectrum of the frequency modulation system is attained and weight, heating, and power consumption of the transmitter are reduced while using it as a nonlinear amplifier.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spread spectrum communication device that uses frequency shift keying for primary modulation.

[Conventional technology]

FIG. 5 is a diagram embodying the conventional spread spectrum system shown in the document ``Latest Spread Spectrum Communication System'' (Jacik Publishing) Figure 2.3. In the figure, 1 is a carrier wave oscillator, 2 is a carrier wave oscillator, This is transmission data, which is input to the exclusive OR circuit 4 together with the output of the pseudo noise (PN) generator 3. 5 performs phase modulation of the output of the carrier wave oscillator 1 using the output of the exclusive OR circuit 4. balanced modulator,
6 is a transmitter that amplifies the output of the balanced modulator 5, and 7 is a transmitting antenna connected to the transmitter 6.

Further, 8 is a receiving antenna, 9 is a receiving amplifier connected to the receiving antenna 8, 10 is a carrier wave oscillator, and 11 is a pseudo noise (P
N) generator; 12 is a balanced modulator that modulates the phase of the output of the carrier wave oscillator 10 with the signal of the pseudo-noise generator 11; 13 is a mixer that despreads the output of the receiving amplifier 9 with the output of the balanced modulator 12; 14 is a a demodulator that demodulates the despread output by phase detection;
15 is received data.

Next, the operation will be explained.

The input transmission data 2 is randomized by the PN generator 3. Here, the bit rate of the PN generator 3 is higher than the symbol rate of the transmission data 2. The output of the exclusive OR circuit 4 is the carrier wave output of the carrier wave oscillator 1 which is phase modulated by the balanced modulator 5 to perform spectrum spreading, and the modulated signal is amplified by the transmitter 6 and radiated as a radio wave by the transmitting antenna 7. be done.

Further, the receiving antenna 8 receives radio waves from the transmitting antenna 7, and the received signal is input to the receiving amplifier 9. On the other hand, the output of the carrier wave oscillator 10 is modulated by a balanced modulator 1 by a PN generator 11.

In this case, the output of the PN generator 11 is synchronized with the PN generator 3 on the transmitting side. Therefore, when the output of the balanced modulator 12 is applied to the mixer 13 as a local oscillation signal, the receiving amplifier 9
The output of the mixer 13 is despread, and the output of the mixer 13 becomes a narrowband phase shift keying output.

When this output is demodulated by the phase detection demodulator 14, the received data 15 is obtained, and the same code sequence as the transmitted data 2 is obtained.

[Problem that the invention seeks to solve]

Conventional spread spectrum devices are configured as described above, so the final transmission output must be phase modulated, the transmitter requires a linear amplifier, and there are problems with weight, heat generation, and power consumption. .

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to obtain a spread spectrum communication device in which a transmitter can be configured with a nonlinear amplifier.

[Means for solving problems]

The spread spectrum communication device according to the present invention includes a plurality of transmitting-side pseudorandom number generating means for generating pseudorandom numbers of mutually different orthogonal code sequences, and a plurality of transmitting-side fJ2 pseudorandom scattered number generators according to transmission data. a selection means for selecting any one of the means, a transmitting side frequency shift modulation means for applying frequency shift modulation to the output of the selecting means to spread the frequency, and each of the above-mentioned transmitting side pseudo-random number generators. a plurality of reception side pseudorandom number generation means for generating pseudorandom numbers synchronized with the means; a plurality of reception side frequency shift modulation means for performing frequency shift modulation on the output of each of the pseudorandom number generation means; The apparatus is provided with a plurality of mixing means for despreading the received signal by mixing it with a received signal, and a determining means for selecting and demodulating a highly correlated signal from among the outputs of these mixing means.

[Effect]

In this invention, any one of a plurality of sequences of pseudo-random numbers is selected according to the transmission data, and the signal is frequency shift keyed and transmitted according to the selected data, and the receiving side communicates with the transmitting side, respectively. The received signal is despread using a frequency shift keyed signal using a plurality of synchronized sequences of pseudo-random numbers, the correlation of each of the plurality of intermediate frequency signals obtained thereby is calculated, and a highly correlated signal is selected and demodulated. This makes it possible to spread the spectrum using frequency modulation, which was previously difficult.
Power consumption is reduced.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 2 is a data input, and 3a to 3d are pseudo noise generators, each of which generates mutually orthogonal code sequences. A selection switch 21 selects the output of the pseudo noise generators 3a to 3d according to the input data series. 22 is a frequency shift modulator that frequency modulates a signal according to the output of the selection switch 21; 6 is a transmitter that amplifies the output of the frequency shift modulator 22; 7 is a transmitter 6
is a transmitting antenna connected to the

Further, 8 is a receiving antenna, 9 is a receiving amplifier connected to the receiving antenna 8, 23a to 23d are pseudo noise generators corresponding to the pseudo noise generators 3a to 3d on the transmitting side, and 243 to 24d.
25a to 25d are mixers that despread the output from the reception amplifier 9 using the outputs of the frequency shift modulators 24a to 24d, and 26a to 26d is mixer 25a~
A bandpass filter detects a signal falling to an intermediate frequency from the output of the bandpass filter 25d, a determiner 27 selects a signal having a high signal level among the outputs of the bandpass filters 26a to 26d, and 15 is output data.

Next, the operation will be explained.

The pseudo-noise generators 3a to 3d always generate code sequences of pseudo-noise (random numbers). In addition, the code sequences have the lowest correlation with each other, that is, orthogonal code sequences are selected.
The selection switch 21 separates the data input every 2 bits,
If it is "11", the output of pseudo noise generator 3a is set, if "00", the output of 3b is set, and if it is "110", the output of 3c is set to 1.
If it is 01', select the 3d output. The selected code sequence is subjected to frequency shift modulation by the frequency shift modulator 22. An example of this frequency shift modulation is shown in FIG. Here, the bit rate of the code sequences of the pseudo-noise generators 3a to 3d is selected to be much higher than the symbol rate of the data input 2, so that the output of the frequency shift modulator 22 is spread spectrum. The output of the frequency shift modulator 22 is amplified by the transmitter 6 and radiated from the transmitting antenna 7.

Further, the receiving antenna 8 receives radio waves from the transmitting antenna 7, and the receiving amplifier 9 amplifies the radio waves.

On the other hand, the pseudo noise generators 23a to 23d generate codes in synchronization with the pseudo noise generators 3a to 3d on the transmitting side. The output of the pseudo noise generator 23a is input to a frequency shift modulator 24a to generate a spread local oscillation signal. Other pseudo noise generators 23b to 23d.

The frequency shift modulators 24b to 24d are also similar to the pseudo noise generator 23a1 and the frequency shift modulator 24a, respectively.

The mixer 25a despreads the output of the receiving amplifier 9 using the spread local oscillation signal of the frequency shift modulator 24a. An example of the despread signal is shown in FIG. In the example in Figure 3, the sender “1”
1'', that is, when the output of the pseudo noise generator 3a is selected and sent, A is the output of the mixer 25a, B is the output of the mixer 25b,
C is the output of 25c, and D is the output of 25d. Also the third
In the figure, fQ is the despread intermediate frequency.

Each output passes through bandpass filters 26a to 26d, and the center of each bandpass filter is fO, and the bandwidth has a characteristic that is roughly the reciprocal of the symbol rate.

The outputs of the bandpass filters 26a to 26d are input to a determiner 27, where the signal with the highest energy is selected. Third
In the example shown in the figure, the signal A has the longest fO period (and has the highest energy), so "11" is output as the data output, and the data is reproduced.

In this embodiment, the transmitter is a non-linear amplifier, and weight/heat generation and power consumption can be reduced compared to the conventional system.

In the above embodiment, there are four types of pseudo noise generators, but the number may be 21, and the same effect as in the above embodiment can be achieved. An embodiment in which there are only two parts is shown in FIG. 4, in which the same reference numerals as in FIG. 1 indicate the same or corresponding parts.

〔Effect of the invention〕

As described above, according to the present invention, any one of a plurality of sequences of pseudo-random numbers is selected according to transmission data, and a signal is frequency-shift keyed according to the selected data, transmitted, and received. On the receiving side, the received signal is despread using a frequency-shift modulated signal using multiple sequences of pseudo-random numbers synchronized with the transmitting side, and the multiple intermediate frequency signals thus obtained are correlated to each other to obtain highly correlated signals. Since selective demodulation is performed, spectrum spreading using the frequency shift keying method, which has been difficult in the past, becomes possible, and the device can be made lighter and smaller by using a nonlinear amplifier as the transmitter.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a spread spectrum communication device according to an embodiment of the present invention, FIG. 2 is a diagram showing an example of a frequency on the transmitting side of the device, and FIG. 3 is a diagram showing an example of a frequency on the receiving side of the device. , FIG. 4 is a diagram showing another embodiment of the present invention, and FIG. 5 is a diagram showing another embodiment of the present invention.
The figure is a configuration diagram of a conventional spread spectrum communication device. 3a-3d...Pseudo noise generator, 22.24a-24
d... Frequency shift modulator, 23a-23d... Pseudo noise generator, 25a-25d... Mixer, 26a-2
6d...band filter, 27...determiner. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A direct spread communication device that generates pseudo-random numbers corresponding to “1” and “0” of the symbols to be transmitted, and transmits the signals by shifting the frequency, and is installed on the transmitting side and is connected to each other. a plurality of transmitting side pseudorandom number generating means for generating pseudorandom numbers of orthogonal code sequences different from each other; and one of the outputs of the plurality of transmitting side pseudorandom number generating means according to the transmission data for each predetermined number of bits. a selection means for selecting, a transmission-side frequency shift modulation means for applying frequency shift modulation to the output of the selection means to spread the frequency, and a transmission means for transmitting the modulated output, provided on the reception side, respectively. a plurality of reception side pseudorandom number generation means for generating pseudorandom numbers synchronized with each of the plurality of transmission side pseudorandom number generation means; receiving side frequency shift modulation means; a plurality of mixing means for mixing the received signal and the output of the receiving side frequency shift modulation means and despreading the received signal; and a correlation among the outputs of the plurality of mixing means. 1. A spread spectrum communication device comprising: determination means for selecting and demodulating a signal with a high signal.