KR20040037737A - UWB impulse signal generator - Google Patents

Abstract

PURPOSE: A signal generator for use in an ultra wide band impulse communication is provided to implement the signal generation and modulation device by filtering a conventional signal and using a simple circuit which is capable of making an asymmetric signal in the form of impulse filtering a conventional signal. CONSTITUTION: A signal generator for use in an ultra wide band impulse communication includes a clock generator block, a timer/counter block and a filter block. The signal generator is characterized in that the asymmetric signal in the form of impulse is made by filtering the rectangular wave at the filter block.

Description

Ultra-wideband impulse communication signal generator {UWB impulse signal generator}

The present invention relates to a UWB (Ultra Wide Band) signal for ultra-high speed communication, and more particularly, the signal generation circuit and the pulse position modulation can be simply implemented by using this signal when implementing a UWB impulse communication system.

Recent advances in electronic technology have made it possible to develop radars and communication devices using extremely short pulses of less than nanoseconds. Devices that use these very short pulses are called "Ultra Wide Band devices", and their bandwidth is generally broadband over 25% of the center frequency (occupied bandwidth / center frequency = 0.25). Apply 10 dB-bandwidth). These devices have been developed in the military and used in part in the 1980s to detect underground deposits. They are applied to many applications such as the government and commercial sectors where data processing technology is used to detect short-range objects and communicate in a multi-propagation path environment. Can be.

A unique feature of UWB technology is the ability to communicate wirelessly without the use of radio frequency (RF) carriers. Instead, UWB uses modulated pulses of energy with a duration of less than 1 nanosecond. Pulse modulation techniques include Pulse Position Modulation (PPM), Pulse Amplitude Modulation (PAM), On-Off Keying (OOK), and Binary Phase Shift Keying (BPSK). Shift Keying), M-ary, etc.

In the future, if a lot of UWB nodes are installed in home entertainment equipment, location and tracking systems, there should be an optimal way to efficiently perform multiple accesses. There are three types of multiple access methods: time-hopping, time division multiple access (TDMA), and code division multiple access (CDMA). I'm using

The advantage of UWB technology is that it detects signals by receiving energy distributed over a wide range, so the immunity to interference caused by narrowband communication signals is very good, the pulse width is very narrow, and the duty cycle is less than 1%. Signal spreading or signal overlapping due to multiple propagation paths can be avoided, and it is also suitable for secure communication because it appears as noise in existing narrowband communication systems. The processing gain increases in inverse proportion to the coefficient, so that the processing gain is very high. Even if a pulse having a high energy is very narrow, the energy is dispersed over a wide band, and thus the spectral power density is very low. No oscillator is required, no linear amplifier is required if there is no high power communication. The system does not use the frequency stage (IF), so the system is simple, broadband service for multiple users is possible by using time division multiple access, and it is suitable for short-range communication because the signal is distributed over a wide band.

As a signal for UWB impulse communication, signals of FIGS. 1, 2, and 3 are used. These signals have a pulse width on the order of 500 psec and enable fast data communication. 1, 2 and 3 signals, complex circuits are used for signal generation and modulation.

The benefits of this ultra-wideband system are partially disclosed through the recently created improved ultra-wideband technology called impulse wireless communication system (hereinafter referred to as impulse radio). First, Impulse Wireless is Larry W. It is fully described in a series of patents, including U.S. Pat.Nos. 4,641,317, 4,813,057, 4,979,186, 5,363,108 and 4,743,906, filed by Larry W. Fullerton. A second patent for impulse radios is disclosed in US Pat. Nos. 5,677,927 and 5,687,169, filed by Fullerton et al.

However, since most pulse position modulation methods are considered, very accurate time synchronization is required for transmission and reception, and since signals are distributed over a very wide band, they may interfere with other communications. It can cause interference or obstacles of other equipment by impulse electromagnetic wave, etc., and has the disadvantage of using a special antenna having excellent broadband frequency characteristics.

Accordingly, an object of the present invention is to provide an ultra-wideband impulse communication signal for filtering an existing symmetrical signal so that an impulse-shaped asymmetric signal is solved. have.

1 is a conventional ultra-wideband single signal.

2 is a conventional ultra-wideband single signal.

3 is a conventional ultra-wideband single signal.

4 is a signal proposed by the present invention.

5 is a diagram showing a signal of the present invention by a signal generator.

6 is a diagram illustrating pulse position modulation using a conventional signal.

7 is a diagram illustrating a pulse train for ultra-wideband impulse communication using a conventional Gaussian monocycle.

8 is a block diagram of a generator and a pulse position modulator.

The above object of the present invention is achieved by a signal for ultra-wideband impulse communication consisting of a clock generator, a timer, a counter, a filter and the like.

The present invention is to use the signal as shown in Figure 4 in the implementation of the UWB impulse communication system. The use of the proposed signal simplifies the implementation of the signal generator and the modulation device.

The signal of FIG. 4 is obtained from the signal generator of FIG. Filters the input square wave to produce an impulse signal. t4 can be adjusted according to the design of a filter. The characteristics of the proposed signal are asymmetrical while the existing signal is symmetrical. It can also be implemented using a simple R / L filter.

6 shows a pulse position modulation method using a conventional signal. As can be seen from Fig. 6, on the basis of a very small signal (Fig. 1), the signals are shifted by δ time to represent 0 and 1.

7 shows a pulse train for UWB impulse communication using a conventional Gaussian monocycle signal.

The use of the proposed signal also has advantages in implementing the pulse position modulation scheme. As can be seen in FIG. 6, signal shift by δ time is important for representing data. Therefore, the modulated signal can be obtained by moving the square wave for signal generation by δ and passing through the filter.

8 shows a block diagram of a generator and a pulse position modulator.

It is divided into clock generator, timer, counter and filter. The clock generator section generates a square wave. At this time, the period of the signal is determined in consideration of the δ time and pulse train period required by the UWB signal.

The timer and counter unit counts the periodic clock inputs, thereby creating a basic signal for implementing a pulse train as shown in FIG. In addition, the spread position modulation is performed by outputting a square wave shifted by δ from the basic period of the pulse train. In other words, a signal for 0 and 1 is generated by changing the value of the counter by 1 from the reference value.

The filter unit filters the square wave from the timer and counter unit to generate the proposed signal.

Therefore, the ultra-wideband impulse communication signal of the present invention by filtering the existing signal to create an impulse-type asymmetric signal, it is possible to implement a signal generation and modulation device using a simple circuit.

Claims (2)

In the ultra-wideband impulse communication signal generator comprising a clock generator unit, a timer / counter unit and a filter unit, Ultrasonic impulse communication signal generator, characterized in that for filtering the square wave to form an asymmetric signal of the impulse type. The ultra wide band impulse communication signal generator according to claim 1, wherein the filter unit is composed of an R / L circuit.