KR20100002311A - Oscillation protecting apparatus of movable base station and method thereof - Google Patents

Abstract

PURPOSE: An oscillation preventing device of a mobile relay system is provided to offset a feedback signal by using an offset signal, thereby preventing the oscillation of a signal. CONSTITUTION: A phase/amplitude measuring unit(112) measures the phase and amplitude of the test signal from an output antenna(20). A signal size adjustment unit(126) adjusts the size of a phase and amplitude measurement signal varied in a variable phase unit(125). An adder(110) adds up the varied phase and amplitude measurement signal with a signal received from an input antenna(10). The adder offsets signal from a transmission antenna. A DSP(Digital Signal Processor)(117) delays the measurement data of the phase/amplitude measuring unit.

Description

Oscillation prevention device and method of mobile relay system {OSCILLATION PROTECTING APPARATUS OF MOVABLE BASE STATION AND METHOD THEREOF}

The present invention relates to an oscillation preventing device and a method of a mobile relay system.

In more detail, when the output antenna and the input antenna are in close proximity, since the signal fed back to the input antenna through the output antenna is combined with the signal transmitted from the base station to act as noise, the phase of the signal fed back through the output antenna, The present invention relates to an oscillation preventing apparatus and a method for automatically generating an offset signal using a signal size and a delay time, and canceling a signal by canceling a feedback signal using an offset signal.

In general, an oscillation prevention device applied to a mobile communication relay system may be classified into an analog oscillation prevention device and a digital oscillation prevention device.

As shown in FIG. 1, the analog oscillation prevention apparatus maintains the separation distance between the output antenna and the input antenna to be above a predetermined interval so as to avoid mutual interference.

As shown in FIG. 2, the digital oscillation prevention device filters the signal received through the input antenna 10 through the band pass filter BPF 11 and then outputs the signal to the down converter D / C 21. The down converters D / C and 21 lower the frequency and output the same to the A / D converters A / D and 22. The received signal converted into the digital signal by the A / D converter 22 is input to the digital signal processor DSP 29.

The digital signal processor (DSP) 29 converts the received digital signal into an analog signal by two connected D / A converters D / A, 27 and 28. The analog signals converted by the two D / A converters 27 and 28, respectively, are input to the comparator Com. 26, and the signals generated as a result of the comparison by the comparator 26 are upconverters U /. C, 23). At this time, the digital signal processor DSP 29 cancels the feedback signal by canceling the feedback signal by measuring time delay, phase, and signal magnitude with respect to the input signal.

The up-converters U / C 23 convert the frequency of the input signal and transmit the converted signal to the output antenna 20 through a high power amplifier (HPA).

3 is another embodiment of a digital oscillation prevention apparatus, comprising: an input antenna 1, a mixer 2 mixing a local frequency and a signal transmitted from a transmission medium received through the input antenna 1 to a reception medium; A band pass filter (4) for lowering the output signal of the mixer (2) to a low frequency band, a summer (14) for summing the signal having the low frequency band and a feedback signal, and amplifying the summed signal An amplifier 15 for distributing the amplified signal, a mixer 15 for distributing the amplified signal, a mixer 6 for mixing the divided signal and a local frequency, and an amplifier for amplifying the mixed signal and transmitting the amplified signal to a receiving medium through an output antenna. And an A / D converter 9 for converting the output signal of the distributor 15 into a digital signal, and receiving a digital signal from the A / D converter 9 to a D signal input thereto. Primary digital delays signal in response Delay section 10, Secondary digital phase delay filter 11, the second digital to finely adjust the signal significantly delayed by the first digital delay section 10 in response to the C [n] signal input from the outside A multiplier 12 for adjusting the amplitude of the signal filtered through the phase delay filter 11 and a D / A conversion for converting the signal output through the multiplier 12 into an analog signal and outputting the analog signal to the summer 14. It consists of a part 13.

At this time, when the signal is amplified by the mixer 6 and finally emitted through the output antenna to reach the antenna of the reception medium, some of the signals radiated to the output antenna are introduced into the input antenna 1.

The operation of the digital oscillation prevention device configured as described above is as follows.

Amplifying the signal of the input antenna applied from the transmission medium to a predetermined level in the amplifier to remove the oscillation caused by the feedback signal between the input and output antenna in the bidirectional or unidirectional wireless repeater having a structure that the transmitting antenna transmits to the receiving medium Apply a dedusting device. That is, the oscillation removing apparatus of FIG. 3 amplifies the signal of the input antenna 1 applied from the transmitting medium to a predetermined level by the amplifier 15 and outputs the output antenna to the receiving medium through the output antenna.

A mixer (2) (6) is added between the input antenna (1) and the amplifier (G), and a bandpass filter (4), a summer (14) and an amplifier (15) between the mixers (2) and (6). ) And the divider 8 are arranged sequentially so that the signal received via the input antenna 1 is mixed with the local frequency 5 by the mixer 2, and thus the signal mixed by the mixer 2 is band The frequency band is lowered while passing through the pass filter 4, and the signal having the lower frequency band is mixed with the signal fed back by the summer 14. At this time, the feedback signal is the same as the magnitude of the signal input from the band pass filter 4, the phase is a signal different 180 degrees.

The signal from which the oscillation disturbance signal is removed through the summer 14 is amplified by the amplifier 15, mixed with the local frequency again through the divider 8 and the mixer 6, and then amplified by the amplifier G. It is sent out via an output antenna.

At this time, the feedback signal generated due to insufficient separation distance of the antenna is removed through the following process. That is, the signal extracted by the distributor 8 is converted into a digital signal through the analog-to-digital converter 9, and the second digital new hole delay filter 11 is subjected to a large delay control in the primary digital delay unit 10. By finely adjusting the delay signal, the amplitude is adjusted in the multiplier 12 and converted into an analog signal through the D / A converter DAC 13. In the summer 14, the feedback signal is added to the mixed original signal. In this case, the applied signal is the same magnitude as the feedback signal and is 180 degrees out of phase.

On the other hand, the adjustment of the delay time according to the distance of the antenna has a large delay adjustment value by the memory arrangement in the primary digital delay unit 10. The delay unit is the inverse of the sampling frequency. In addition, the secondary digital signal delay filter 11 has an extremely fine phase difference by calculating and adjusting it according to the delay time to which the filter coefficient C [n] is applied in order to finely adjust the time corresponding to the inverse of the sampling frequency. It is structured to be controlled by. The adjustment of the amplitude can be finely adjusted with high precision numerically in the multiplier 12.

The analog oscillation prevention apparatus described with reference to FIGS. 1A and 1B has a problem in that the separation distance of the antenna must be maintained at a predetermined interval in order to ensure isolation between signals.

In addition, the digital oscillation prevention apparatus described with reference to FIGS. 2A and 2B is a BPF (Bandpass Filter, 11) for input signals coming from the direction of the base station, rather than maintaining the separation distance of the antenna to secure the separation. And a LNA (Low Noise Amplifier) 13 extract the signal in the forward direction of the base station where the feedback signal is combined and convert it to the IF frequency band using the down converter 21.

The A / D converter 22 converts the digital signal into a digital signal. The digital signal is separated from the feedback signal and the base station signal by the digital signal processor 29 to cancel the feedback signal, and the base station signal is D / D. A is converted to an analog signal in the IF frequency band. The converted analog signal is converted into a signal in the RF frequency band by using the up converter 23 and is enhanced through the HPA 17 to radiate to the shaded (service) area through the output antenna 20. In this method, since the analog signal is oscillated in the LNA 11, which is a step before converting the digital signal, there is a problem in that the oscillation removal technique has a limitation even when the oscillation prevention technique is applied by converting it to a digital signal.

That is, the analog oscillation preventing device as shown in FIGS. 1A and 1B should simply secure the space between antennas to remove the oscillation, and the digital oscillation preventing device as shown in FIGS. 2A and 2B may secure the space between antennas rather than the analog oscillation prevention relay system. Although it may be free, the digital oscillation prevention device also has a problem in that the space between the antennas is secured to some extent because oscillation occurs in the input antenna when the space between the antennas is not secured to some extent.

The present invention has been made to solve the above problems of the prior art, an object of the present invention is to transmit a signal fed back to the input antenna through the output antenna at the base station when the output antenna and the input antenna is in close proximity Since it is combined with the signal and acts as a noise, the offset signal is automatically generated by using the phase, signal size, and delay time of the signal fed back through the output antenna, and the feedback signal is canceled by using the offset signal to prevent oscillation of the signal. An oscillation preventing apparatus and a method thereof for a mobile relay system can be provided.

In order to achieve the above object, an embodiment of the present invention, the oscillation prevention device of the mobile relay system, a signal generator for generating a test signal; A first D / A converter converting the test signal output from the signal generator into an analog signal; An output antenna for transmitting a test signal of the first D / A converter; A phase / amplitude measuring device that receives a test signal transmitted through the output antenna through an input antenna and measures a phase and an amplitude of the input test signal; A second D / A converter converting phase and amplitude measurement information of the phase / amplitude measuring instrument into an analog signal; A 180 degree phase shifter which receives a phase and amplitude measurement signal of the second D / A converter and converts a phase of the phase by 180 degrees; A variable phase shifter configured to vary a phase of a phase and amplitude measurement signal whose phase is 180 degrees converted in the 180 degree phase shifter; A signal magnitude adjusting unit configured to adjust magnitudes of phase and amplitude measurement signals having a variable phase in the variable phaser; A summer for adding up the variable phase and amplitude measurement signals with a received signal received through the input antenna to cancel a signal transmitted through the transmit antenna; And a digital signal processor configured to receive and delay the phase and amplitude measurement data of the phase / amplitude meter and output the delayed phase and amplitude measurement data.

In addition, another embodiment of the present invention, in the oscillation prevention method of the mobile relay system, (1) generating a test signal; (2) transmitting the test signal through an output antenna; (3) measuring the phase and amplitude of the feedback signal of the output antenna through the input antenna, and delaying and outputting the measured phase and amplitude information and the clock signal; (4) receiving the phase and amplitude information and the delayed clock signal and converting the phase and amplitude information into an analog signal in response to a clock signal; (5) converting the phase of the analog-converted signal by 180 degrees; (6) adjusting a phase of the 180-degree phase shifted signal; (7) generating a cancel signal by adjusting the magnitude of the phase-adjusted signal; And (8) summing the cancel signal and the signal received through the input antenna to cancel the signal fed back from the output antenna.

As described above, in the present invention, when the output antenna and the input antenna are in close proximity, the signal fed back to the input antenna through the output antenna is combined with the signal transmitted from the base station to act as noise, and thus the signal fed back through the output antenna. Using the phase, the signal size and the delay time of the offset signal is automatically generated, and the offset signal is canceled by using the offset signal, it is possible to prevent the oscillation of the signal.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention in detail.

The configuration of the oscillation preventing device of the mobile relay system according to the present invention will be described with reference to the drawings.

The oscillation prevention apparatus of the mobile relay system includes an input antenna 10, a duplexer 100 for processing a signal received from the input antenna 10, an LNA 111, A phase / amplitude measuring instrument 112 for measuring a phase and an amplitude of a signal output through the LNA 111 and outputting a phase and amplitude measuring signal, and a phase and amplitude measuring signal output from the phase / amplitude measuring instrument 112 And an RF processor 113 for processing a base station signal output through the LNA 111, an RF switch 114 for outputting a signal processed by the RF processor 113, and a signal generator for generating a test signal. 115, an A / D converter 116 for converting the signal output from the signal generator 115 into a digital signal, and a first signal for processing the signal converted into the digital signal and outputting the converted signal to the output antenna 20. Outputs digital signals to the path, while phase and signal A digital signal processor 117 for outputting the digital signal to a second path for converting the first signal; and a first D / A converter for converting a test signal or a base station signal output from the digital signal processor 117 into an analog signal ( 118, an output antenna 20 for transmitting a test signal or a known station signal of the first D / A converter 118, and a signal for converting a signal output from the digital signal processor 117 into an analog signal. Phases of the 2D / A converter 122, the clock delay unit 123 for delaying the clock input to the second D / A converter 122, and the second D / A converter 122; A 180 degree phase shifter 124 that receives an amplitude measurement signal and converts its phase by 180 degrees, and a variable position that varies the phase of the phase and amplitude measurement signal whose phase is 180 degrees converted by the 180 degree phase shifter 124 And the phase in the variable phaser 125 A signal magnitude adjusting unit 126 for adjusting the magnitude of the changed phase and amplitude measurement signals, and adding the variable phase and amplitude measurement signals to the received signal received through the input antenna 10 to output the output antenna 20. It consists of a summer 110 to cancel the signal sent through.

The second D / A converter 122 measures the size of the signal while delaying the signal input from the 180-degree phase shifter 124 using a reference time set arbitrarily and measures the magnitude of the measured signal as a result of the measurement. The time when M is the smallest is recognized as the delay time generated between the output antenna and the input antenna.

When the second D / A converter 122 is set to the rising edge, the second D / A converter 122 delays the conversion time of the analog signal by delaying the clock when converting the data into an analog signal based on the data when the clock jumps from low to high.

The variable phaser 125 calculates the minimum time and the maximum time of the delay time generated between the output antenna and the input antenna by using the minimum distance and the maximum distance of the mutual separation distance between antennas in the field.

5 is a configuration diagram of a digital part of the oscillation prevention apparatus to which the present invention is applied, and an oscillator (100M VCXO, 231) is connected to the digital signal processor 230, and is connected to the click buffer 232 to the oscillator 231. The click generator 222 is connected to the clock delayer 223 to the clock buffer 232 to delay the click signal input to the first D / A converter 221 under the control of the clock controller 224. To control.

The click buffer 232 controls the clock generator 233 to input a clock signal to the second D / A converter 211.

Referring to the operation of the oscillation prevention device of the mobile relay system configured as described above are as follows.

First, the signal input to the repeater is composed of a signal from the base station and a radiated signal, that is, the output signal of the relay directly coming from the output antenna to the input antenna.

In the oscillation prevention relay system to which the present invention is applied, it is intended to prevent oscillation by sensing a signal directly coming from the output antenna 20 to the input antenna 10 and attenuating it at the front end of the input LNA 111.

In other words, when the analog signals having the same signal magnitude, the same time difference, and the opposite phases are added to the analog signal, the signal disappears. In addition, in a system such as the present repeater, since the signal level directly coming from the output antenna to the input antenna causes the largest oscillation, the present invention implements an output oscillation repeater system for attenuating and eliminating the oscillation phenomenon caused by the direct incoming signal. .

In more detail, a signal such as a forward signal directly input through the input antenna is generated by the digital signal processor 117 and summed into an analog signal state through the summer 110 through the summer 110 in front of the LNA 111 after the input antenna. To attenuate the oscillated signal.

In order to attenuate or cancel the oscillation signal as described above, it is necessary to know the signal size, the same time difference, and the inverted phase. In the present invention, the signal magnitude and the inverted phase are used to convert the signal output from the signal generator 115 into the phase / amplitude measuring instrument 112. The time difference can be measured by measuring the time difference and output the signal from the signal generator 115 to find the equipment delay time, the delay time between the output antenna and the input antenna and give a time delay from the calculated minimum to the maximum value Measure by 126 to find when the signal level is input the smallest. As described above, the measured time is the time delay time between the output antenna 20 and the input antenna 10 of the present invention.

The method for measuring the phase of the test signal output from the signal generator 115 will be described. The signal generator 115 before the A / D converter 116 inputs the level test test signal to the A / D converter. 116, the digital signal processor 117, the first D / A converter 118, and the signal processor 119, which outputs through the HPA 120 and the output antenna 20, and directly enters the input antenna 10. Is input to the phase / amplitude measuring unit 112 at the rear end of the LNA 111, and the phase / amplitude measuring unit 112 measures the phase difference with respect to the output signal.

That is, the phase difference between the output antenna and the input antenna can be measured using the test signal output from the signal generator 115.

As described above, the phase and signal magnitude information are input to the digital signal processor 117, and the digital signal processor 117 is input to the second D / A converter 122 through the second path and converted into an analog signal. At this time, the second D / A converter 122 converts the data into an analog signal when the clock is in a rising edge or falling edge state.

Referring to FIG. 6, a process of finely adjusting the fine adjustment action of the second D / A converter 122 to 10 ns or less will be described. The second D / A converter 122 is set to the rising edge. When considered, the clock shifts from low to high to an analog signal based on the data. By using this, the clock is delayed from 0 ns to 10 ns to delay the time when the analog signal converted by the second D / A converter 122 changes. In other words, the delay from 0ns to 10ns is divided into three stages, 0 ~ 2.4ns, 2.55ns ~ 7.5ns, and 7.65ns ~ 9.9ns.

That is, to adjust the time delay of the oscillated signal, the adjustment of 10 ns or more is controlled by using the digital signal in the digital signal processor 117, and the fine adjustment of 10 ns or less is performed by using the method of FIGS. 8 to 13. The fine adjustment is made by the / A converter 122. Detailed description of this fine adjustment portion will be described later with reference to the drawings.

7 illustrates the time axis of the rising edge or the falling edge of the data and the clock of the D / A converter. If the second D / A converter 122 is set to the rising edge, the clock is set low to high. The data is converted into an analog signal based on the moment when the signal is changed, and the data is converted into an analog signal when the clock is changed from high to low by the falling edge.

As described above, the delayed analog phase / amplitude measurement signal is input to the 180-degree phase shifter 124 and the phase is 180 degrees inverted to be directly radiated. The phase / amplitude measurement signal in which the phase is converted to 180 degrees is input to the variable phase shifter 125 again and the phase is finely adjusted once again.

The phase is inverted, and the phase / amplitude measurement signal whose phase is finely adjusted once again is input to the signal magnitude adjusting unit 126.

Then, the signal amplitude adjusting unit 126 outputs the signal generated by the signal generator 115 before the A / D converter 116 through the output antenna 20 to output the signal directly coming into the input antenna after the LNA 111. The phase / amplitude measuring instrument 112 measures the attenuation of the signal magnitude relative to the output signal. That is, since the signal output from the signal generator 115 is the signal output in the present invention, the attenuated signal magnitude between the output antenna and the input antenna can also be measured. The measured information is passed through the second D / A converter 122 in the second path and output to the signal adjuster 126 to attenuate the magnitude of the signal between the output antenna and the input antenna of the first path. Attenuated as much as possible so as to be adjusted to the same signal size as the directly radiated signal is output to the summer 110 in front of the LNA (111).

In order to have the same time difference, which is the last condition for the signal attenuation, first, the time taken for the signal output through the output antenna to be directly input to the input antenna must be measured.

In the increaser system to which the present invention is applied, the time is not measured as an absolute value, but using the principle that the signal size is canceled by analogizing the signal of the signal size, the phase reversed 180 degrees, and the same time as described above. The signal size and inverted phase state are measured and set in the same manner as described above, and a time delay of 0.15 ns is used for the time delay of the output antenna and the input antenna. For example, when delayed from 0ns to 0.15ns to 10ns, the signal size at 0ns is -20db, the signal size at 10ns is -30db, and the signal size at 6.75ns is -40db, which is the smallest in the interval. If so, the time delay between the output antenna and the input antenna of the present invention is 6.75ns. Here, the time delay ranges of minimum time and maximum time giving time delay are set as follows.

Assuming that the distance between antennas in the field is 5 to 10 meters, the propagation speed of a direct incoming signal is measured and found by giving a delay of 0.15 ns from the calculated time difference at 5 meters to the calculated time difference at 10 meters.

The travel time of radio waves at 5 meters is approximately 5 / (3 * 100,000,000) = 5 / 3ns (1.677ns), and the travel time at 10 meters is approximately 10 / (3 * 100,000,000) = 10 / 3ns ( 3.333 ns). By adjusting from 1.667ns to 3.333ns in steps of 0.15ns, the signal input from the dual signal sizing unit 126 is found to be the lowest, and the measurement time is set as the delay time. After setting the signal magnitude, phase, and time delay measured through the above process, the digital signal processor 117 outputs a signal input from an input antenna rather than a signal input from the signal generator 115 through an output antenna. Ensure oscillation protection service is provided. By the method according to the present invention to prevent the oscillation signal coming directly from the output antenna of the input antenna to the input antenna to enable a smooth service even when the input and output antennas are close.

Finally, the second D / A converter 122 will be described with reference to FIGS. 8 to 16 as follows.

FIG. 8 illustrates the time axis of the D / A converter input of the data and the clock when no time delay is applied, and in the middle of the data as shown in FIG. 8 to smoothly convert the digital signal into an analog signal. The clock should rise. In this case, if the clock rises before or after the middle of the data, the analog conversion is not performed normally because the data changes at the rising moment of the clock, that is, at the moment of conversion from the digital signal to the analog signal.

9 is a diagram illustrating a time axis for input of a second D / A converter of data and a clock when a 2.4 ns time delay is applied. As shown in FIG. 9, when the clock is delayed by 2.4 ns in units of 0.15 ns, the analog signal converted by the second D / A converter 122 is also delayed by 2.4 ns in units of 0.15 ns from 0 ns. have. This is because the second D / A converter 122 is performed when the clock is rising. If a delay of 2.4 ns is applied, the second D / A converter 122 changes the data after 2.6 ns after the clock rising time. It can be seen that the timing margin of 122 is sufficient.

FIG. 10 illustrates a time axis for input of a second D / A converter of data and a clock when a 2.55 ns time delay is given, and the second D / A converter is configured with a delay of 5 ns for data. When the input signal is input to 122 and the clock is delayed from 2.55 ns in time, the analog signal is also delayed from 2.55 ns through the second D / A converter 122. This is because the second D / A converter 122 is performed when the clock is rising. In addition, if the delay starts from 2.55ns, the timing rise of the D / A converter is sufficient because the clock rising time is 2.55ns after the data is changed.

FIG. 11 is a diagram showing the time axis of the D / A converter input of the data and the clock when the 7.5 ns time delay is applied. The 11 D / A converter 122 delays the data for 5 ns. It can be seen that the converted analog signal is also delayed from 7.5 ns when the digital data is converted into an analog signal through the second D / A converter 122 while delaying the clock from 7.5 ns with respect to the reference. This is because the second D / A converter 122 performs an operation of converting digital data into an analog signal when the clock is rising. In addition, when the delay is performed from 7.55 ns time, the clock rise time after the data is changed is 2.5 ns, which means that the timing margin of the second D / A converter 122 is sufficient.

FIG. 12 is a diagram illustrating a time axis for input of a second D / A converter of data and a clock when a 7.65 ns time delay is applied, and the second D / A converter 122 is delayed for 10 ns of time. After converting the digital data into an analog signal through the second D / A converter 122 while delaying the clock from 7.65ns time from the reference, it can be seen that the converted analog signal is also delayed from 7.65ns time. . This is because the second D / A converter 122 performs an operation of converting digital data into an analog signal when the clock is rising. In addition, if the delay is given from the 7.65 ns time, since the clock rising time is 2.65 ns after the data is changed, it is understood that the timing margin of the second D / A converter 122 is sufficient.

FIG. 13 is a diagram illustrating a time axis for input of a second D / A converter of data and a clock when a 9.9 ns time delay is given. The second D / A converter 122 is delayed for 10 ns of data. If the digital data is converted into an analog signal through the second D / A converter 122 while the clock is delayed from 9.9 ns in the reference, it can be seen that the converted analog signal is also delayed from the 9.9 ns time. . This is because the second D / A converter 122 performs an operation of converting digital data into an analog signal when the clock is rising. In addition, if the delay is applied from the 10 ns time, since the clock rising time is 5 ns after the data is changed, it can be seen that the timing margin of the second D / A converter 122 is sufficient.

FIG. 14 illustrates a time axis in which 100M data is delayed by 5ns and 100M clock by 5ns. The data is also delayed by 5ns and input to the second D / A converter 122, and the clock is 5ns in reference. When the digital data is converted into an analog signal through the second D / A converter 122 while being delayed, it can be seen that the converted analog signal is also delayed from 5 ns time. In addition, it can be seen that the timing margin of the second D / A converter 122 is sufficient because the data is changed after 5 ns time after the rising time of the clock when the delay is performed up to 5 ns time.

FIG. 15 illustrates a time axis in which 100M data is delayed to 5ns only without giving a time delay, and this data is input to the second D / A converter 122 without a time delay. By delaying to 5ns from the reference, the second D / A converter 122 converts the digital data into an analog signal, so that the D / A conversion is smoothly performed because the clock is rising in the section where the digital data is changed. You won't lose.

FIG. 16 illustrates a time axis in which 100M data is delayed to 7.5ns only without giving a time delay, so that the data is input to the second D / A converter 122 without a time delay. When the digital data is converted into an analog signal by the second D / A converter 122 while the clock is delayed by 7.5 ns from the reference, the rising state of the clock at the time when the data is changed and the data of the next section is inputted. Because of this, it can not be said that the analog signal gave a time delay. As shown in FIG. 15 and FIG. 16, if only the clock is delayed, the analog conversion is not converted stably, and when the analog signal is converted, the time delay is not accurate. Only with this method can digital data be reliably converted into analog signals and accurate time delays can be achieved.

As mentioned above, although preferred embodiments of the present invention have been described in detail, those skilled in the art to which the present invention pertains may make the present invention without departing from the spirit and scope of the present invention as defined in the appended claims. It will be appreciated that various modifications or changes can be made.

1 is a view for explaining the analog oscillation prevention apparatus according to the prior art.

2 is a view for explaining a digital oscillation prevention apparatus according to the prior art.

3 is another embodiment of FIG. 2.

4 is a view for explaining the configuration of the oscillation prevention device of the mobile relay system according to the present invention.

5 is a block diagram of a digital part of the oscillation prevention apparatus to which the present invention is applied.

FIG. 6 is a diagram illustrating a process of converting a digital signal into an analog signal by inputting data and a clock into a D / A converter.

FIG. 7 is a diagram for describing a time axis of a rising edge or a falling edge of data and a clock of a D / A converter.

FIG. 8 is a diagram illustrating a time axis of a D / A converter input of data and a clock when no time delay is applied.

9 is a diagram illustrating a time axis for input of a second D / A converter of data and a clock when a 2.4 ns time delay is applied.

FIG. 10 is a diagram illustrating a time axis for input of a second D / A converter of data and a clock when a 2.55 ns time delay is given.

FIG. 11 is a diagram illustrating a time axis of an input of a D / A converter of data and a clock when a 7.5 ns time delay is given.

FIG. 12 illustrates a time axis for input of a second D / A converter of data and a clock when a 7.65 ns time delay is given.

FIG. 13 is a diagram illustrating a time axis for input of a second D / A converter of data and a clock when a 9.9 ns time delay is given.

FIG. 14 is a diagram illustrating a time axis in which 100M data is delayed by 5ns and 100M clock by 5ns.

FIG. 15 is a diagram illustrating a time axis in which 100M data is delayed to 5ns only without giving a time delay.

FIG. 16 is a diagram illustrating a time axis in which 100M data is delayed up to 7.5ns without giving a time delay.

<Description of the symbols for the main parts of the drawings>

100: duplexer 110: summer

111: LAN 112: phase / amplitude measuring instrument

113: RF processing unit 114: RF switch

115: signal generator 116: A / D converter

117: Digital signal processor 118: First D / A converter

119: signal processor 120: duplexer

121: HPA 122: second D / A conversion unit

123: clock delay unit 124: 180 degree phase shifter

125 variable phase shifter 126 signal amplitude adjustment unit

Claims (8)

In oscillation prevention device of mobile relay system, A signal generator for generating a test signal; A first D / A converter converting the test signal output from the signal generator into an analog signal; An output antenna for transmitting a test signal of the first D / A converter; A phase / amplitude measuring device that receives a test signal transmitted through the output antenna through an input antenna and measures a phase and an amplitude of the input test signal; A second D / A converter converting phase and amplitude measurement information of the phase / amplitude measuring instrument into an analog signal; A 180 degree phase shifter which receives a phase and amplitude measurement signal of the second D / A converter and converts a phase of the phase by 180 degrees; A variable phase shifter configured to vary a phase of a phase and amplitude measurement signal whose phase is 180 degrees converted in the 180 degree phase shifter; A signal magnitude adjusting unit configured to adjust magnitudes of phase and amplitude measurement signals having a variable phase in the variable phaser; A summer for adding up the variable phase and amplitude measurement signals with a received signal received through the input antenna to cancel a signal transmitted through the transmit antenna; And A digital signal processor which receives and delays phase and amplitude measurement data of the phase / amplitude meter and outputs delayed phase and amplitude measurement data; Oscillation prevention device of a mobile relay system, characterized in that it comprises a. The method of claim 1, The second D / A converter measures the size of the signal while delaying using a reference time set arbitrarily with respect to the signal input from the 180-degree phase converter, and at the moment when the measured signal size becomes smallest. An oscillation preventing apparatus of a mobile relay system, characterized in that the time is recognized as a delay time generated between the output antenna and the input antenna. The method of claim 2, The second D / A converter may delay the conversion time of the analog signal by delaying the clock when converting the digital data into the analog signal when the clock jumps from low to high when the rising edge is set to the rising edge. Rash prevention device. The method of claim 1, The variable phase shifter may calculate a minimum time and a maximum time of a delay time generated between the output antenna and the input antenna by using the minimum distance and the maximum distance of mutual separation distances between antennas in the field. Oscillation prevention device. The method of claim 1, Oscillation prevention device of the mobile relay system, And a clock delayer for delaying a clock with respect to delayed phase and amplitude measurement data output from the digital signal processor. In the oscillation prevention method of the mobile relay system, (1) generating a test signal; (2) transmitting the test signal through an output antenna; (3) measuring the phase and amplitude of the feedback signal of the output antenna through the input antenna, and delaying and outputting the measured phase and amplitude information and the clock signal; (4) receiving the phase and amplitude information and the delayed clock signal and converting the phase and amplitude information into an analog signal in response to a clock signal; (5) converting the phase of the analog-converted signal by 180 degrees; (6) adjusting a phase of the 180-degree phase shifted signal; (7) generating a cancel signal by adjusting the magnitude of the phase-adjusted signal; (8) canceling the signal fed back from the output antenna by summing up the cancellation signal and the signal received through the input antenna; Oscillation prevention method of a mobile relay system, characterized in that consisting of. The method of claim 6, In step (7), the size of the signal is measured while delaying the signal input from the 180-degree phase shifter using an arbitrarily set reference time, and the time at which the measured signal size becomes the smallest is outputted. Oscillation prevention method of a mobile relay system, characterized in that it is recognized as a delay time generated between the antenna and the input antenna. The method of claim 6, In the step (4), when the clock is set to the rising edge, when converting the analog signal based on the data when the clock jumps from low to high, the clock is delayed to delay the conversion time of the analog signal. How to prevent rashes.

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