JPS6025354A - Radio communication system - Google Patents

Abstract

PURPOSE:To prevent the deterioration in the ratio of carrier to the noise of a carrier by applying ASK modulation to the carrier subjected to PSK modulation or FSK modulation with a sub-modulation signal in synchronizing with a main modulation signal and converted into the combination of 1, 0 and 0, 1 codes. CONSTITUTION:The digitized main modulation signal (1) is fed to a PSK modulator PSK-MOD, the sub-modulation signal (4) is fed to a signal processing S and a clock signal (2) is applied to the both. Further, the output of a carrier oscillator in the PSK modulator PSK-MOD is subjected to PSK modulation by the main modulation signal and the result is outputted from a terminal (3). The carrier from the terminal (3) is subjected to the ASK modulation further by a signal (5) processed at the signal processing section S by an ASK modulator ASK- MOD, the signal is subjected to frequency conversion and amplification at a transmission section TX and transmitted to an opposite station from an output terminal OUT. The reception station demodulates the signal and extracts the signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a wireless communication system, and more particularly to a wireless communication system for transmitting digital information using complex modulation.

(bl) Prior Art and Problems FIG. 1 is a block diagram of a conventional example for performing wireless communication using 1) SK/ASK (phase shift keying/amplitude shift keying) modulation method.

In the figure, depending on the main modulation signal applied to the input terminal lN-1, the PSK modulator PSK -MOD'? : The carrier wave is PSE-modulated and then this PSK-modulated (the general transmission wave is applied to the input terminal lN-2. For example, the sub-modulation signal composed of a digitized meeting signal or a small amount of data is used as an ASK modulator. The signal is ASK (amplitude shift keying) modulated by ASK-MOD, converted into the necessary transmission frequency and power by the transmitter TX, and then transmitted from the output terminal OUT to the partner station.

On the receiving side, the received signal applied to the input terminal IN is amplified and frequency-converted in the receiving section RX, and then divided into two.
One is applied to the phase demodulator PSK-DEH, and the main modulation signal is taken out from the output terminal OUT-1. The remaining portion is applied to an ASK detector ASK-DET, where a sub-modulation signal is extracted. The taken out sub-modulation signal is applied to the reproducing circuit R, where the waveform is regenerated and sent to the output terminal OUT -2.
taken out to the outside.

Figure 2 shows the psK/
Shows harmonics to 8SK.

In the same figure, since the PSK-modulated carrier wave is modulated by Δsy, the amplitude of this carrier wave fluctuates, and the amplitude of the part a is smaller than the other parts ff. There was a problem in that the carrier-to-noise ratio deteriorated.

(C1 Purpose of the Invention The present invention was made in view of the problems of the prior art described above, and it is possible to perform ΔSK modulation on a carrier wave modulated by PSK or FSK without deteriorating the carrier-to-noise ratio of the carrier wave. The aim is to provide a wireless communication method that is easy to use.

(di Structure of the Invention The object of the above invention is to provide a main modulation signal and a sub-modulation signal
/ASK change R round again Ha FSK /ASK change 1 round I
In a wireless communication system in which an I transmission wave is transmitted from the transmitting side and the received carrier wave is differentially demodulated on the receiving side to extract the main modulation signal and the sub-modulation signal, synchronization with the main modulation signal is performed. The PSK-modulated or FSK-modulated carrier wave is then
This is achieved by providing a wireless communication system characterized by k modulation.

tel Embodiment of the Invention FIG. 3 is an example of a block connection diagram for implementing the present invention.

In the figure, PSK-MOD means PSK modulator, eight SK-M
OP is the SK transformer, TX is the transmitter, S is the signal processor, PSK-DEM is the PSK demodulator, RX is the receiver, 8SK-DHT is the SK detector, R is the SK detector. In the reproducing circuit, IN-1, IN-2, and IN each represent an input terminal, OUT-L OUT-2, and OUT each represent an output terminal, and CLK represents a clock input terminal.

Note that the same reference numerals as in FIG. 1 indicate the same parts.

Each block is connected as follows.

The input terminal ■ of the PSK modulator PSK-MOD is connected to the input terminal lN-1, and the input terminal ■ is connected to the clock input terminal CLK.

The output terminal 3 is connected to the output terminal OUT via the Ask modulator ΔSK -MOD and the transmitter TX, the input terminal ■ of the signal processing section S is connected to the input terminal TN-2, and the input terminal ■ is connected to the input terminal CL.
K and the output terminal S-1 are respectively connected to the input terminal (2) of the ASK variable piece 4SK-Month OD.

In addition, the output terminal 01JT-1 of the psKi summer conditioner PSK-DnH and the demodulator PSK-DIEM
Is the input terminal of the receiving section 1? °C input α111 child I through X
N, the output terminal of the reproducing circuit R is connected to 0UT-2, and the input terminal (2) is connected to the output terminal (2) of the receiving section RX via an ASK detector ASK-DET.

The dotted line portion is the portion added to the plug connection diagram of FIG. 1 in order to implement the wireless communication system of the present invention.

FIG. 4 shows a specific circuit example of the signal processing section S shown in FIG.

In the figure, I)TV represents the frequency division H:I, INV represents the inverter, N-1 to N-4 each represent a NAND circuit, and s-1 represents the output terminal.

Each part is connected to the following.

The input α11.1 of the frequency divider D1ν is the clock input terminal CLK, and the output terminals 0 and 0 are the NAND circuit N-
1 and N-2 input terminals [phase] and ■, NAND circuit N
The further inputs α11]-1 and N-2 are respectively connected directly and via an inverter INV to the input terminal IN-2. The output terminals @ and 0 of the NAND circuits N-1 and N-2 are connected to the output terminal S-1 via the NAND circuits N-3 and N-4.

Figure 6 shows the ASK detector ASK-DET shown in Figure 3.
An example of a more detailed block connection diagram is shown.

In the figure, ENV represents an envelope detector, DL represents a 1-bit delay circuit, and PD represents a phase detector.

Fig. 5 is a diagram for explaining the operation of each block shown in Figs. The waveform of the part with the same number shown in is shown.

Therefore, the operation of each block shown in FIG. 3 will be explained with reference to FIG. 5.

In FIG. 3, the digitized main modulation signal is applied to the PSK modulator PSK-MOD from the input terminal IN-1 (see FIG. 5).

A sub-modulation signal is applied to the input terminal 4 of the signal processing section S from the input terminal IN-2 (see FIG. 5).

Then, the clock signal is input from the input terminal CLK to the PSK variable m.
PSK-MOD and the input terminal 2 of the signal processing section S (see FIG. 5).

The main modulation signal and the sub-modulation signal are synchronized by this clock signal.

Then, the main modulation signal applied to the PSK modulator PSK-MOD performs PSK modulation on the output of a carrier wave oscillator (not shown) in this modulator PSK-MOD, and the PSK-modulated carrier wave is taken out from the terminal (See Figure 5 ■).

Next, the PSK-modulated carrier wave taken out from the terminal
The signal is then subjected to the processing described later at the terminal S-1 (see Figure 5 ■), further subjected to ASK modulation, frequency converted and amplified by the transmitter TX, and sent from the output terminal OUT to the other station. (See Figure 5 ■).

The received signal is sent to the receiving unit 17 via the input terminal IN of the receiver.
After being amplified and frequency converted by X, the receiving section RXOθ1!
It is taken out from the first child (■) (see Figure 5 ■).

Then, the signal obtained at terminal ■ is divided into two, and one signal is demodulated by the PSK modulator PSK-MOD using a differential demodulation method in which the difference with the previous carrier wave component is demodulated by one bit, and the main modulation signal is output. It is taken out to terminal OUT -1 (Fig. 5 ■).

On the other hand, the remaining signal is detected by the ASK detector ASK-D, which will be described later.
It is detected by ET and the sub-modulation signal is taken out (see Figure 5 ■)
.

This sub-modulation signal is regenerated by a reproducing circuit R to extract the original sub-modulation signal.

FIG. 4 shows a more specific circuit example of the signal processing section S, and the operation of this portion is as follows.

The clock signal applied to the clock terminal CLK (see Figure 5 ■) is divided in half by the frequency divider DIV, and outputs whose phases are inverted from each other are obtained from the terminal q and the clock (see Figure 5 [
phase], see ■).

These two clock signals are applied to the terminal [phase] of NAND circuit N-1 and the terminal (2) of N-2.

On the other hand, part of the sub-modulation signal shown in Figure 5
N-2 is directly applied to another input terminal of the NAND circuit N-1 and another input terminal of the NAND circuit N-2 through the inverter INV, and the outputs of the NAND circuits N-1 and N-2 are connected to the NAND circuit. In addition to the input terminals @ and 0 of N-3, respectively,
When the output of the NAND circuit N-3 is applied to the input terminal ■ of the NAND circuit N-4, the output terminal S-1 is synchronized with the main modulation signal and is converted into a combination of codes 1.0, 0, 1. Weird εj!
A J signal is obtained (see Fig. 5 @~■ and ■).

This sub-modulation signal further transmits the PSK modulated wave to the child mentioned above.
Change δjjJ.

FIG. 6 is a block connection diagram showing an embodiment of the tJ,/IsI+ detector.

Throughout, 1iNV represents an envelope detector, DL represents a 1-pin 1-delay circuit, and PD represents a phase detector.

In the same figure, -ζ, PSK added to human power D::j child■
The amplitude modulation of the /I'IsK modulated wave (see Figure 5 -) is detected by the envelope detector ENV (see Figure 5 -).

Part of this detected wave is a direct phase detector PD
Then, the rest is a delay circuit fI81 that delays by one pin of the sub-modulation signal and is input to another input 011 of the phase detector PD.
The sub-modulated signal 5J is applied to the output terminal 1, and the sub-modulated signal 5J is output from the output terminal 2 after being subjected to various phase comparisons (see Fig. 5 2).

In addition, this kind of frying, '1. 'l' S Khen 8JU
Possible methods include 2-phase 14-phase, 8-phase PSK modulation, FSX modulation, 1ζ2-phase, 4-phase FSK modulation, and the like.

(fl As described in the detailed description of the invention, PSK modulation is performed by further ASK modulating a carrier wave that has been PSK modulated or FSK modulated with a sub modulation signal that is synchronized with the main modulation signal and converted into a combination of codes of 1, 0, and 0.1.
/ASK modulated wave or FSK /ASK modulated wave is sent to the other station, but as shown in Figure 5 (■), the sign of 1.0 appears alternately in this wave except at the conversion point of the sub-modulation signal, and at the conversion point, The situation is such that the sign of 1 or O increases by 1 bit.

The partner station uses a differential demodulation method in which it demodulates by taking the difference between the main modulation signal contained in the received wave and the main modulation signal contained in the received wave, which is the transmitted wave of the previous bit. Since the amplitude and the amplitude of the valley portion are used, the carrier-to-noise ratio becomes uniform, and deterioration caused by superimposition of sub-modulation signals can be eliminated.

[Brief explanation of the drawing]

Figure 1 shows conventional PSK/SK modulation or FSK/A
An example of a professional connection diagram for implementing a wireless communication system using SK modulation, Fig. 2 is a diagram for explaining received waveforms, and Fig. 3 is an example of a block connection diagram for implementing the present invention. 4 shows a specific circuit example of the signal processing section shown in FIG. 3, FIG. 5 shows a diagram for explaining the operation of FIG. 3, and FIG. 2A and 2B are block connection diagrams showing one embodiment of an ASK detector. In the figure, PSK-MOD means PSK modulator, eight SK-M
OD is the SK modulator, TX is the transmitter, S is the signal processing section, PSK-DE is the old PSK demodulator, RX is the receiving section, ΔSK-DET is the ASK detector, R is the regeneration circuit , lN-1, IN -2, IN is the input terminal, OUT
-1, OUT -2, OUT indicates an output terminal, and CLK indicates a clock input terminal. 1st Old 2nd Figure 5 口■-■L for river M----11 几■■■■ ■ 6th ARK-DET

Claims (1)

[Claims] A carrier wave modulated with PSK/ASK or FSK/ASK with a main modulation signal and a sub-modulation signal is transmitted from the transmitting side, and the receiving side differentially demodulates the received carrier wave to generate the main modulation signal and sub-modulation signal. In a wireless communication system that extracts a
SI (a wireless communication system characterized by ASK modulation of a modulated carrier wave).