KR100852276B1 - Adjustable chaotic signal generator and generating method thereof - Google Patents

Abstract

The present invention relates to a variable chaos signal generator and a chaos signal generating method, wherein the chaos signal generator comprises a plurality of triangular wave generators for generating a plurality of triangular waves having different frequency periods, and a triangular wave from each triangular wave generator. And an FM modulator for raising the signal output from the mixer to a predetermined frequency band and outputting a chaotic signal. As a result, the power consumption can be reduced, the cost can be reduced, and the chaos signal generator can be easily manufactured as the device is integrated with the IC. In addition, a plurality of users may use wireless communication within a certain wireless communication zone.

Chaos Signal, Generator, Triangle Wave, SAW, Amplitude Control, DC Bias, FM Modulation, VCO

Description

Variable chaos signal generator and its chaos signal generation method {ADJUSTABLE CHAOTIC SIGNAL GENERATOR AND GENERATING METHOD THEREOF}

1 is a block diagram of a chaos signal generator for ultra-wideband communication according to the present invention;

2 (a) to 2 (d) are graphs showing triangular waves generated by four triangular wave generators,

3 is a waveform diagram of a noise signal output from the mixer of FIG. 1;

4 (a) and 4 (b) is a graph showing a waveform of the chaotic signal output from the voltage controlled oscillator according to the amplification gain control of the amplitude controller of FIG.

5 is a graph illustrating spectral characteristics of a waveform of a chaotic signal output from the voltage controlled oscillator of FIG. 1;

6 is a graph showing a waveform of the chaotic signal of FIG. 5 on a time axis;

7 (a) to 7 (c) are graphs showing the waveforms of the chaotic signals output from the voltage controlled oscillator according to the DC bias value adjustment of the DC bias controller;

8 is a flowchart illustrating a process of generating a chaotic signal using a chaotic signal generator according to the present invention.

Explanation of symbols on the main parts of the drawings

 1 Chaos Signal Generator 5 Triangle Wave Generator

10: mixer 15: amplitude controller

20 DC bias controller 25 voltage controlled oscillator

The present invention relates to a variable chaotic signal generator and a chaotic signal generation method thereof, and more particularly, to a variable chaotic signal generator and a chaotic signal generation method for reducing power consumption and facilitating adjustment of the center frequency and bandwidth. It is about.

Recently, wireless communication schemes using ultra-wide frequency bands of 3.1 GHz to 5.1 GHz have been developed in addition to Bluetooth, and according to the proposal of the IEEE 802.15.4a standard, a scheme of transmitting information using chaotic signals has been developed. One of them.

IEEE 802.15.4a is a location-aware, low-power sensor network standardization group that adds location and low-power capabilities to the hybrid technology of 802.15.4 (ZigBee, Zigbee) and 802.15.3 (UWB: Ultra Wide Band). It is the next generation communication field.

Here, the chaos signal modulation scheme proposed for the implementation of the low power function. The chaotic signal modulation method can be designed with a simple RF structure in hardware and does not require circuits such as VCO, PLL, and mixer required in the conventional wireless communication system. Accordingly, when the chaotic signal modulation method is used, the power consumption can be reduced to 10mW, which is 1/3 of the conventional power consumption.

The core of such chaotic signal modulation is a chaotic signal generator that generates a wideband chaotic signal. The existing chaotic signal generator generates a chaotic signal in an ultra wide frequency band of 3.1 GHz to 5.1 GHz, and the generated chaotic signal is turned on or off by an OOK (On Off Keying) modulation method and converted into a chaotic carrier.

However, since the chaotic signal generated by the chaotic signal generator takes the form of a single signal having the full frequency band of the ultra-wide band, when a plurality of users use a wireless device in a certain wireless communication zone, the same channel is used. Mutual interference occurs. Thus, only one wireless device can transmit and receive radio signals at a time within a certain wireless communication zone. That is, it is not possible to use a frequency division multiplexing (FDM) scheme that allows a plurality of users to communicate within a certain wireless communication zone using a plurality of frequency channels.

In addition, since the chaotic signal is generated over the entire frequency band of the ultra-wide band and has a strong nonlinearity, power consumption is large.

Accordingly, the chaos signal generator can generate a chaos signal according to a frequency band, that is, a channel, so that the FDM method can be applied to allow a plurality of users to simultaneously wirelessly communicate in a predetermined wireless communication zone. It will be necessary to find ways to reduce power consumption.

Accordingly, it is an object of the present invention to provide a chaotic signal generator and a chaotic signal generating method thereof that are variable to reduce power consumption and to easily adjust the center frequency and the frequency bandwidth so that a plurality of users can communicate wirelessly at the same time. .

The configuration of the present invention for achieving this object comprises a plurality of triangular wave generator for generating a plurality of triangular waves having different frequencies from each other; A mixer for mixing each triangle wave from each triangle wave generator to output a noise signal; And an FM modulator configured to output the chaotic signal by raising the noise signal to a predetermined frequency band.

The triangle wave generator may be a saw tooth generator.

It is preferable that the period of the triangular wave generated by each of the triangular wave generators is formed to be a few times.

The FM modulator may be a voltage controlled oscillator whose band of oscillation frequency is adjusted according to the applied voltage.

And an amplitude controller for controlling the amplitude of the noise signal to adjust a frequency bandwidth of the chaotic signal output from the FM modulator.

The amplitude controller is a variable amplifier, the frequency bandwidth of the chaos signal can be adjusted according to the amplification gain of the variable amplifier.

The amplitude controller adjusts the amplification gain to determine the frequency bandwidth of the chaotic signal to match the width of the channel.

And a DC bias controller for adjusting the center frequency of the chaotic signal output from the FM modulator by adjusting the DC bias applied to the noise signal.

As the DC bias value applied by the DC bias controller increases, the center frequency of the chaotic signal may increase.

The DC bias controller may vary the center frequency of the chaotic signal to match the frequency band of the channel.

On the other hand, the object is a step of generating a plurality of triangle waves having mutually different frequencies; Generating a noise signal by mixing the triangle waves; And generating a chaotic signal by raising the noise signal to a predetermined frequency band.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a chaos signal generator for ultra-wideband communication according to the present invention.

The chaotic signal generator 1 generates a chaotic signal in a desired frequency band for communication, and includes a plurality of triangular wave generators 5 (Triangle Pulse Train Generator), a mixer 10 (Adder), an amplitude controller 15, and a DC. The bias controller 20 includes a voltage controlled oscillator 25 which is an FM modulator.

The triangular wave generator 5 may use a saw tooth (AW (Surface Acoustic Wave)) generator that generates a sawtooth wave, and the frequencies of the triangular waves generated by the triangular wave generators 5 are different from each other. Although only four triangular wave generators 5 are illustrated in FIG. 1, if the number of triangular wave generators 5 is two or more, a chaotic signal may be generated. However, as the number of the triangular wave generators 5 increases, the chaotic signal output from the voltage controlled oscillator 25 may be more complicated.

The triangular waves generated by the triangular wave generators 5 have different pulse widths as the frequencies differ from each other. The period ratio of the triangular waves generated by the triangular wave generators 5 is preferably formed by a small number of times, that is, 2 times, 3 times, 5 times, 7 times, 11 times, and 13 times. For example, when the period T of the triangular wave generated by one triangular wave generator 5 is 2 nS, the other triangular wave generator 5 generates a triangular wave having a period of 3 nS, and the other triangular wave generator 5 generates a triangular wave. Generate 5nS triangle wave. Such a triangular wave generator 5 generally generates a sawtooth wave by configuring a voltage detector and a discharge circuit in an RC charging circuit or a constant current circuit, and changing the RC value or the constant current value can change the period.

The reason why the period of the triangular wave generated by each triangular wave generator 5 is made to be a fractional multiple is to minimize the overlap of the triangular waves generated by each triangular wave generator 5. If the period ratio of the triangular waves generated by the triangular wave generators 5 is a multiple of each other or an inverse, the triangular waves overlap each other in the harmonic frequencies, and the power of the triangular waves increases in the region where the triangular waves overlap. When the power of the triangular wave increases, the high power power amplifier (not shown) connected to the rear end of the amplitude controller 15 and the chaotic signal generator 1 needs to process a large signal, so that the amplitude controller 15 and the power amplifier Not only should the capacity be large, but also high linearity must be ensured. Therefore, the overall power consumption of the system is increased and the cost is increased by using expensive devices.

The mixer 10 mixes a plurality of triangle waves generated from each triangle wave generator 5 to generate a noise signal. At this time, since the triangle ratio input to the mixer 10 has a small period ratio, since mutual overlap between the triangle waves is minimized, the power of the noise signal output from the mixer 10 has a uniform distribution. In other words, since the peak-to-average power ratio (PAPR) is small, the linearity of the amplitude controller 15 is not required.

The amplitude controller 15 is provided with a variable amplifier, and the variable amplifier adjusts amplification gain in accordance with the magnitude of the applied voltage. The amplitude controller 15 adjusts the frequency bandwidth of the chaos signal output from the voltage controlled oscillator 25 by adjusting the amplification gain of the noise signal provided from the mixer 10. At this time, the greater the voltage applied to the amplitude controller 15, the greater the amplification gain, and the greater the amplification gain, the greater the frequency bandwidth of the chaotic signal. On the contrary, when the voltage applied to the amplitude controller 15 becomes small and the amplification gain becomes small, the bandwidth of the chaotic signal is reduced.

The amplification gain adjusted by the amplitude controller 15 may be determined according to the channel width of the RF communication system in which the chaotic signal generator 1 is mounted. For example, when the channel width of the RF communication system is large, the amplification gain of the amplitude controller 15 is increased to increase the frequency bandwidth. When the channel width of the RF communication system is small, the amplitude of the amplitude controller 15 is amplified. By reducing the gain, the frequency bandwidth can be reduced.

The DC bias controller 20 provides a DC bias to the noise signal, and the center frequency of the chaotic signal output from the voltage controlled oscillator 25 is adjusted by the DC bias. The DC bias controller 20 changes the center frequency of the chaotic signal by adjusting the DC bias value. At this time, the range of the center frequency adjustable by the DC bias controller 20 varies linearly according to the applied DC bias value. The larger the DC bias value, the higher the center frequency, and the smaller the DC bias value, the center frequency. Becomes lower. In this way, since the center bias of the chaos signal can be changed by the DC bias controller 20, the chaos signal corresponding to each channel used in the RF communication system can be generated.

The DC bias controller 20 may change the center frequency by adjusting the DC bias value according to the communication state of the channel. For example, when the channel environment changes and the communication status of the channel is degraded, or when another wireless communication device using the same channel enters the same communication area, the DC bias value applied to the DC bias controller 20 is adjusted. You can change the channel.

The voltage controlled oscillator 25 generates a chaotic signal by adjusting the frequency of the noise signal in accordance with the voltage control. The voltage controlled oscillator 25 (VCO: Voltage Controlled Oscillator) is an oscillator whose oscillation frequency changes according to a change in applied voltage, and receives a noise signal to generate a chaotic signal in a desired frequency band. While the triangular wave generator 5 oscillates a triangular wave near the baseband, the voltage controlled oscillator 25 generates frequencies in the MHz to GHz frequency band. Therefore, when the frequency band of the noise signal is increased in the voltage controlled oscillator 25, the wavelength is shortened, so the noise signal is converted into a very dense chaotic signal. The range of the oscillation frequency output from the voltage controlled oscillator 25 is larger than the DC bias controller 20 depending on the applied voltage.

2 (a) to 2 (d) are graphs showing triangular waves generated by four triangular wave generators.

If the period of the triangular wave generated by the triangular wave generator 5 shown in FIG. 2 (a) is doubled, the triangular wave shown in FIG. 2 (b) has three times the period. The period of the triangular wave shown in FIG. 2 (c) is five times, and the period of the triangular wave shown in FIG. 2 (d) is seven times.

As the period of each triangular wave is made up of a multiple of a few, the mutual interference of each triangular wave can be minimized.

3 is a waveform diagram of a noise signal output from a mixer.

When the triangle wave from each triangle wave generator 5 is mixed in the mixer 10, as shown in Fig. 3, a noise signal formed like noise is output. This noise signal is provided to the amplitude controller 15 and the DC bias controller 20.

4 (a) and 4 (b) are graphs showing waveforms of chaotic signals output from the voltage controlled oscillator according to the amplification gain adjustment of the amplitude controller. 4 (a) and 4 (b) are both measured by adjusting only the gain of amplification when the center frequency is 4 GHz, that is, while the DC bias is fixed.

4 (a) is measured in the state where the amplification gain of the amplitude controller 15 is increased, and the gain at the center frequency (m1) of 4 GHz is 7.452 dBm, which is about 10 dBm, and the frequency bandwidth at -4.358 dBm is 2.8. GHz.

On the other hand, Figure 4 (b) is measured while the amplification gain of the amplitude controller 15 is lowered, the gain at the center frequency (m1) 4GHz is 11.078dBm, the frequency bandwidth at 0.977dBm which is about 10dBm difference Becomes 1.2 GHz.

Accordingly, it can be seen that increasing the amplification gain of the amplitude controller 15 increases the frequency bandwidth, and decreasing the amplifying gain of the amplitude controller 15 decreases the frequency bandwidth.

FIG. 5 is a graph showing spectral characteristics of the waveform of the chaos signal output from the voltage controlled oscillator, and FIG. 6 is a graph showing the waveform of the chaos signal of FIG.

5 shows a waveform of a chaotic signal having a center frequency of 3 GHz, and the gain of the center frequency region of the chaotic signal is high. When the chaos signal is transmitted and received during wireless communication, the wireless communication device detects only the chaos signal having a predetermined gain or more. Therefore, a chaos signal of a certain gain or more can be used as a channel.

This chaotic signal, as shown in Figure 6, the size of each pulse is relatively uniform. That is, it can be seen that the PAPR of the chaotic signal is small. This is because the period of the triangular wave generated in each triangular wave generator 5 is designed to be a multiple of a few, it can be seen as a result of the interference between each triangular wave is minimized.

7 (a) to 7 (c) are graphs showing the waveforms of the chaotic signals output from the voltage controlled oscillator according to the DC bias value adjustment of the DC bias controller.

7 (a) to 7 (c) are waveforms of the chaotic signal output when the DC bias value applied to the DC bias controller is increased in steps.

The center frequency of the chaos signal shown in FIG. 7 (a) is 3 GHz, but when the DC bias value is increased, the center frequency of the chaos signal rises to 4 GHz, and the DC bias value is further increased. Increasing, the center frequency of the chaos signal rises to 5GHz, as shown in FIG. As such, by adjusting the DC bias value applied to the DC bias controller 20, the channel can be adjusted.

8 is a flowchart illustrating a process of generating a chaotic signal using a chaotic signal generator according to the present invention.

First, a plurality of triangle wave generators 5 generate a plurality of triangle waves having different frequencies from each other (S810). Each triangular wave is provided to the mixer 10, and the mixer 10 generates a noise signal by mixing each triangular wave (S820).

The noise signal is provided to the amplitude controller 15 to change the amplitude (S830). At this time, in accordance with the adjustment of the amplification gain of the amplitude controller 15, the frequency bandwidth of the chaos signal output from the voltage controlled oscillator 25 is adjusted. I can regulate it.

The amplified noise signal is provided to the DC bias controller 20, and a DC bias value corresponding to the channel is applied to the DC bias controller 20 so that the chaotic signal corresponding to the desired channel is output (S840).

The noise signal to which the DC bias is applied is provided to the voltage controlled oscillator 25, and the voltage controlled oscillator 25 generates a chaotic signal by decreasing the wavelength while raising the noise signal to a desired frequency band (S850). At this time, by adjusting the amplification gain in the amplitude controller 15 and the DC bias value in the DC bias controller 20, the chaotic signal having the desired center frequency and the desired frequency bandwidth in the voltage controlled oscillator 25. Is output. That is, the chaos signal generator 1 may output a chaos signal of which channel and bandwidth are adjusted.

As described above, in the chaotic signal generator 1 according to the present invention, the triangular wave generator 5 can be used to easily generate a noise signal and minimize interference between the triangular waves, thereby reducing the PAPR of the output chaotic signal. Therefore, since it is not necessary to increase the linearity of the amplitude controller 15, not only power consumption can be reduced but also cost can be reduced.

In addition, by adjusting the amplification gain, the frequency bandwidth of the chaotic signal can be adjusted, and the center frequency of the chaotic signal can be adjusted by adjusting the DC bias value, so that not only a plurality of channels can be configured but also the bandwidth of the channel can be adjusted. Do. Accordingly, since each user can use different channels, interference between users does not occur, and accordingly, a plurality of users can use wireless communication within a certain wireless communication zone.

On the other hand, the chaos signal generator 1 is not only simple in configuration and small in size, but also easy to manufacture as it is composed of devices that can be integrated in an IC.

As described above, according to the present invention, it is possible to reduce the power consumption and to reduce the cost, and to simplify the manufacture of the chaotic signal generator as it is composed of devices that can be integrated in the IC. In addition, a plurality of users may use wireless communication within a certain wireless communication zone.

Further, in the detailed description of the present invention, specific embodiments have been described, which should be taken as exemplary, and various modifications may be made without departing from the technical spirit of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the claims below, but also by the equivalents of the claims.

Claims (14)

A plurality of triangle wave generators for generating a plurality of triangle waves having mutually different frequencies; A mixer for mixing each triangle wave from each triangle wave generator to output a noise signal; And, And an FM modulator for raising the noise signal to a predetermined frequency band and outputting a chaotic signal. The method of claim 1, The triangle wave generator is a chaos signal generator, characterized in that the saw tooth generator. The method of claim 1, The period of the triangular wave generated by each of the triangular wave generator, the chaotic signal generator, characterized in that formed by a few times. The method of claim 1, The FM modulator is a chaos signal generator, characterized in that the voltage-controlled oscillator is adjusted the band of the oscillation frequency in accordance with the applied voltage. The method of claim 1, And a amplitude controller for controlling the amplitude of the noise signal to adjust a frequency bandwidth of the chaos signal output from the FM modulator. The method of claim 5, wherein The amplitude controller is a variable amplifier, chaos signal generator characterized in that the frequency bandwidth of the chaos signal is adjusted in accordance with the amplification gain of the variable amplifier. The method of claim 6, The amplitude controller adjusts the amplification gain to determine the frequency bandwidth of the chaos signal to match the width of the channel. The method of claim 1, And a DC bias controller for adjusting a center frequency of the chaos signal output from the FM modulator by adjusting the DC bias applied to the noise signal. The method of claim 8, And the center frequency of the chaos signal increases as the DC bias value applied by the DC bias controller increases. The method of claim 9, The DC bias controller, the chaos signal generator, characterized in that for changing the center frequency of the chaos signal to match the frequency band of the channel. Generating a plurality of triangle waves having mutually different frequencies; Generating a noise signal by mixing the triangle waves; And, Generating a chaotic signal by raising the noise signal to a predetermined frequency band. The method of claim 11, The triangular wave generated in the step of generating the triangular wave, Chaotic signal generation method, characterized in that the period of each triangular wave is a fractional multiple. The method of claim 11, And adjusting the frequency bandwidth of the chaotic signal by controlling the amplitude of the noise signal. The method of claim 11, And adjusting a center frequency of the chaos signal by adjusting a DC bias applied to the noise signal.

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