KR20070029306A - Signal converter and combine performance improving method of the transmitter of rf signal - Google Patents

Abstract

A signal converter of an RF signal transmitter and a method for improving combine performance are provided to enhance the combine performance of a combiner by harmonizing the amplitudes, phases, and time delays of input signals of the combiner in case of increasing the output power of RF signals to be transmitted. A signal converter of an RF signal transmitter consists of a signal characteristic converter(201), a predistorter(202), an up-converter(203), a signal selector(204), a down-converter(205), and a controller. The signal characteristic converter(201), controlling the amplitudes, phases, and time delays of input signals, split and inputted from a splitter, detects and outputs the characteristic of a received reflected wave signal. The predistorter(202) predistorts and outputs the output signal of the signal characteristic converter(201). The up-converter(203) executes digital-to-analog conversion and frequency-up conversion on output signals of the predistorter(202) and outputs an RF signal(401). The signal selector(204) segments the RF signal(401), outputs one of the segmented signals to the first fixed attenuator(310), and outputs the original signal to an external combiner. The signal selector(204) also divides a reflected wave signal(403), reflected and inputted from the external combiner, and outputs them to the second fixed attenuator(311). The down-converter(205) performs frequency-down conversion and analog-to-digital conversion on a forward signal(402) and the reflected wave signal(403) and outputs them to the signal characteristic converter(201) and the predistorter(202). The controller outputs control signals for the amplitudes, phases, and time delays of input signals to the signal characteristic converter(201) according to the reflected signal characteristic information outputted from the signal characteristic converter(201).

Description

Signal converter and combine performance improving method of the transmitter of RF signal

1 is a schematic block diagram of a base station transmitter of a mobile communication system in the prior art,

2 is a block diagram of a signal converter of a base station transmitter according to an embodiment of the present invention.

3 is a schematic block diagram of a base station transmitter equipped with the signal converter of FIG.

4 is a flowchart illustrating a process of a method of improving signal combine performance of a base station transmitter according to the present invention.

Description of the main symbols in the drawings

1: splitter section 2: power amplifier section

3: Combiner 4, 107: Main control

101: channel card 102: channel card output signal

103: signal converter (103a to 103d: first to fourth signal converter)

103 ': signal converter

104: signal converter output signals 104a to 104d: first to fourth signal converter output signals

107: main controller

201: signal characteristic conversion unit

301: time delay 302: variable attenuator

303: phase shifter 304: signal detector

202: predistortion

203: up-converter part

305: digital-to-analog converter (DA converter)

306: up-converter 307: large power amplifier

204: signal selection unit

308: coupler 309: circulator

310: first fixed attenuator 311: second fixed attenuator

312: RF switch

205: down-converter

313: down converter

314: analog to digital converter (AD converter)

206: control unit

410: RF signal 402: forward signal

403: reflected wave signal 404: switch control signal

The present invention relates to a high frequency signal transmission apparatus, and more particularly, to a high frequency signal transmitter for improving the combine performance when combining and amplifying after dividing into at least one or more of the same signal to increase the transmission power of the high frequency signal to be transmitted The present invention relates to a signal converter and a method of improving the combine performance.

In general, a high frequency signal transmitter used in a mobile communication base station uses a method of dividing and amplifying an output signal into a plurality of identical signals in order to increase a transmission output, and then resynthesizing and transmitting the output signal.

1 is a schematic block diagram of a base station transmitter in the above-described prior art.

As shown in FIG. 1, a base station transmitter of a conventional mobile communication system includes a splitter 1 for separating an input RF signal such as a subscriber signal and a splitter 1 separated by the splitter 1, respectively. A power amplifier 2 (first to fourth power amplifiers 2a to 2d) for high power amplification of the RF signal, and a combiner unit for synthesizing the RF signals amplified by the power amplifier 2, respectively. (3).

In the conventional base station transmitter having the above-described configuration, the first to fourth power amplifiers 2a to 2d perform high power amplification of each RF signal separated by the splitter unit 1, and then combiner unit ( 3) synthesizes and outputs a high power amplified RF signal 104 by the first to fourth power amplifiers 2a to 2d.

The combiner portion 3 mainly uses a switchable combiner to cope actively with a small insertion loss and the number of combines in order to increase the transmission power in the base station transmitter.

In addition, since the combiner unit 3 uses simple power distribution and synthesis techniques, only the RF signal having the same signal characteristics, that is, the same amplitude, the same time delay, and the same phase, has excellent signal synthesis characteristics and signal characteristics. In this other case, deterioration of the synthesized characteristics causes the reflected wave signal to be input to the first to fourth power amplifiers 2a to 2d of the power amplifier 102. Therefore, each of the first to fourth power amplifiers 2a to 2d uses a power amplifier having the same output and characteristics.

Therefore, the above-described base station transmitter has a problem in that a combination of power amplifiers of other products is used when combining transmit powers. In particular, a base station using a digital predistortion transmitter has a problem in that a system cannot be implemented because the digital signal cannot be received because the channel card signal is digital.

In addition, since the combiner does not provide a control method for a signal input to the combiner for improving the combiner performance, when the combiner performance is not good, the combiner performance may not be improved without replacing the equipment.

In addition, the combiner unit composed of a switchable combiner or the like combines signals having different phase, gain, and delay characteristics when combining the output signal of the digital predistorter, between input signals of the switchable combiner unit. Reflected wave signals are generated depending on the phase, gain, and delay characteristics, and the reflected wave signals are converted into heat at the termination resistance of the isolator, thereby reducing the lifespan of the base station.

As a result, the Wilkinson combiner unit is used as a method of increasing the power, but a system that considers the through type and combine type is not used because a new structure must be used to convert from the through type to the combine type. Accordingly, there is a need for an apparatus and method for improving new combine performance.

The present invention is to solve the above-mentioned problems in the prior art, combine performance in the combiner by matching the amplitude, phase, time delay of the signals input to the combiner to increase the transmission power in the mobile communication base station It is an object of the present invention to provide a signal changer and combine performance improvement method of a base station transmitter which can extend the life of the base station transmitter by removing the reflected wave signal generated from the combiner.

The signal converter of the high frequency transmitter of the present invention for achieving the above object includes a signal characteristic conversion unit for controlling the output of the amplitude, phase, and time delay of the input signal, and detects and outputs the characteristics of the received reflected wave signal; A predistortion unit for predistorting and outputting the output signal of the signal characteristic conversion unit; An up-converter unit for converting the output signal of the predistortion unit into digital analog and then adjusting the frequency upward to output an RF signal; A signal selector for dividing the signal output from the upconverter and separating and outputting the divided signal and the reflected wave signal input from the outside; A down converter for outputting the divided signal output from the signal selector and the reflected wave signal to the signal characteristic converter and the predistorter after analog-to-digital conversion; And a control unit for outputting a control signal for the amplitude, phase, and time delay to the signal characteristic conversion unit according to the characteristic information of the reflected wave signal output from the signal characteristic conversion unit.

The signal characteristic converting unit may include a time delay unit for adjusting a time delay of the input signal under the control of the controller; A variable attenuator for controlling the amplitude of the input signal under the control of the controller; A phase shifter for controlling the phase of the input signal under the control of the controller; And a signal detector for detecting a characteristic of a digital reflected wave signal input from the down converter.

The signal selector includes: a coupler for dividing and outputting an output RF signal of the upconverter; A circulator for outputting the RF signal output from the coupler to the outside and dividing and outputting the reflected wave signal input from the outside; And a switch which is switched under the control of the controller to selectively switch the reflected wave signals output from the coupler and the circulator to output to the down converter.

The signal selector includes: a coupler for dividing and outputting an output RF signal of the upconverter; A fixed attenuator for attenuating and outputting the divided RF signal output from the coupler; A circulator for outputting the RF signal output from the coupler to the outside and dividing and outputting the reflected wave signal input from the outside; A second fixed attenuator configured to attenuate and output the reflected wave signal output from the circulator; And a switch which is switched under the control of the controller to selectively switch the RF signal of the first fixed attenuator and the reflected wave signal output from the second fixed attenuator to output to the down converter.

Combine performance improvement method of the high frequency signal transmitter of the present invention for achieving the above object is a high frequency signal transmitter having at least one signal toilet for converting and outputting at least one signal input to the combiner, A signal detection process of detecting, by each of the signal characteristic converters, at least one signal input to a binner and a reflected wave signal reflected from the combiner; A standing wave ratio detection step of detecting a standing wave ratio of the signal detected in the signal detection step; And a signal conversion process of controlling an input signal of the signal converter by using the standing wave ratio detected in the standing wave ratio detection process.

In the combined performance improvement method of the high frequency signal transmitter of the present invention for achieving the above object, if the reflected wave signal is detected again from the combiner after the signal conversion process, the process returns to the signal detection process and repeats the process. Characterized in that it further comprises a feedback signal conversion process.

The signal conversion process is characterized by controlling the amplitude, phase, time delay of the signal input to the signal converter to match the amplitude, phase, and time delay of the output signal of the signal changer.

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

2 is a block diagram of a signal converter of a base station transmitter as a high frequency transmitter according to an embodiment of the present invention, and is a schematic block diagram of the base station transmitter equipped with the signal converter of FIG.

As shown in FIG. 2, the signal converter according to an exemplary embodiment of the present disclosure controls and outputs an amplitude, a phase, and a time delay of an input signal input by being split in a splitter 101 such as a channel card. A signal characteristic converter 201 which detects and outputs the characteristic of the reflected wave signal; A predistortion unit 202 for predistorting and outputting the output signal of the signal characteristic conversion unit 201; An up-converter unit 203 for converting the output signal of the predistortion unit 202 into a digital analogue and then adjusting the frequency upward to output the RF signal 401; The signal output from the up-converter unit 203 is divided and output one signal (hereinafter referred to as "forward signal") 402 of the divided signal to the first fixed attenuator 310, and the original signal is A signal selector 204 for outputting to the combiner portion 105 and separating the reflected wave signal 403 reflected and input from the combiner portion 105 and outputting it to a second fixed attenuator; Frequency down-regulation of the forward echo signal 402 and the reflected wave signal 403 output from the signal selector 205, followed by analog-to-digital conversion and output to the signal characteristic converter 201 and predistorter 202 Section 205; And a control unit 206 for outputting the control signal for the amplitude, phase, and time delay to the signal characteristic conversion unit 201 according to the characteristic information of the reflected wave signal output from the signal characteristic conversion unit 201.

The signal characteristic conversion unit 201 converts an input signal to match the amplitude, phase, and time delay of the signals input from the splitter unit 101, and a time delay unit 301 for controlling the time delay of the input signal. Wow; A variable attenuator 302 for controlling the amplitude of the input signal whose time delay is controlled by the time delay unit 301; A phase shifter 303 for controlling the phase of the amplitude controlled input signal in the variable attenuator 302; The signal detector 304 detects the intensity of the reflected wave signal input from the down converter unit 205 and outputs it to the control unit 206.

The up-converter 203 includes a digital-to-analog converter (hereinafter referred to as an "AD converter") 305 for converting an input signal controlled and output from the signal characteristic converter 201 into an analog signal; An up-converter 306 for converting an analog signal output from the AD converter 305 into an RF signal by adjusting the frequency up; And a high power amplifier (hereinafter referred to as "HPA") 307 which amplifies and outputs the RF signal output from the up converter 306.

The signal selector 204 divides the output RF signal of the up-converter 203, and outputs one RF signal to the combiner 105, and another RF signal (forward signal) 402 A coupler 308 outputting to the 1 fixed attenuator 310; The first fixed attenuator 310 and the combiner 105, which attenuates the intensity of the reflected wave signal 403 output from the coupler 308, block the input of the reflected wave signal inputted to the coupler 308 and reflect the reflected wave. A circulator 309 which separates the signal 403 and outputs it to the second fixed attenuator 311; A second fixed attenuator 311 for attenuating and outputting the reflected wave signal 403 output from the regulator 309; The RF switch 312 selectively switches the forward signal 402 output from the first fixed attenuator 310 and the reflected wave signal 403 output from the second fixed attenuator 311 to the down converter unit 205. It consists of.

The down converter 205 converts the downlink signal 402 or the reflected wave signal 403 inputted from the signal selector 204 into a baseband signal and outputs the down converter. (down-converter) 313; A signal detector of the predistorter 302 and the signal characteristic converter 201 converts the baseband signal output from the down converter 313 into a digital signal and then converts the digitally converted forward signal 402 and the reflected wave signal 403. An analog-to-digital converter (hereinafter referred to as "AD converter") 314 input to 304 is configured.

As shown in FIG. 3, the signal converter 103 of the base station transmitter having the above-described configuration includes the first to Nth signal converters 103a of the plurality of stages between the channel card 101 and the switchable combiner 106. 103n), which is composed of a signal converter 103 'and operates under the control of the main controller 107 for controlling the base station system.

That is, the signal converter 103 'receives the channel card output signals 102 of the channel card 101, performs signal characteristic conversion, predistortion, and up-converting, and outputs them to the switchable combiner 105. After detecting the reflected wave signal reflected and input by the switchable combiner 105, the amplitude, phase, and time delay of the channel card output signals 102 are adjusted so that the reflected wave signal does not occur in the switchable combiner 105. It converts to match and outputs it to the switchable combiner 105.

In the first to nth signal converters 103a to 103n having the above-described configuration, the output signal 401 of the high power amplifier 307 is output as the forward signal 402 through the coupler 308 and the fixed attenuator 310. do. The RF signal reflected by the switchable combiner 105 is output as the reflected wave signal 403 through the circulator 309 and the fixed attenuator 109.

The forward signal 402 and the reflected wave signal 403 are controlled by the RF switch 312 and the RF switch control signal 404 and applied to the signal detector 304 through the down-converter 205. . At this time, in order to know the performance of the switchable combiner 105, the control unit 206 calculates the standing wave ratio by detecting the power of the forward signal 402 and the reflected wave signal 403.

A description of a method for improving combine performance in a base station transmitter according to an embodiment of the present invention having the above-described configuration is as follows.

The forward signal 402 and the reflected wave signal 403 are calculated by measuring the magnitude of the signal in the signal detector 304 and applying it to the controller 206.

Each of the output signals 104a to 104n generated by the input signals 102a to 102n passing through the signal converter 103 is Acosω _c t, Bsin [(ω _c (t-α) + θ ₁ ], Ccos [( ω _c (t-β) + θ ₂ ], .... For Ncos [(ω _c (t-η) + θ _N ], the combine signal 106 of the switchable combiner 106 is Acosω _c t + Bsin [(ω _c (t-α) + θ ₁ ] + Ccos [(ω _c (t-β) + θ ₂ ] + .... + Ncos [(ω _c (t-η) + θ _N ] Where A ≠ B ≠ C ≠ ... N, α ≠ β ≠ γ ... ≠ η, θ ₁ ≠ θ ₂ ≠ ... ≠ θ _N, then at the input of the switchable combiner unit 150 The reflected wave signal is generated to increase the combine loss, and heat is generated in the fixed attenuator 311.

At this time, the time delay unit 301, the variable attenuator 302, and the phase shifter 303 of each of the first to Nth signal converters 103a to 103n of the signal converter unit 103 'are transferred to the control unit 206. If A = B = C = ... = N, α = β = γ = ... = η = 0, θ ₁ = θ ₂ = θ ₃ = .... = θ _N = 0 The combine signal 106 of the combine combiner 106 becomes NAcosω _c t, and there is no loss, and no reflected wave signal is generated, thereby making it possible to construct a stable system.

4 is a flow chart showing the detailed processing of the present invention.

Hereinafter, a method of improving combine performance of the high frequency signal transmitter of the present invention will be described with reference to FIGS. 1 to 4.

As shown in FIG. 4, in the method of improving the combine performance of the high frequency signal transmitter of the present invention, first, the signal converter 103 receives the same signals that are split and output from the splitter 1 such as the channel card 101. To the combiner unit 3 such as the switchable combiner 105 and the signal converter 103 is input to the combiner unit 3 such as the switchable combiner 105. The signal 402 and the reflected wave signal 403 reflected from the combiner unit 3 are detected (S1).

Subsequently, when a switch such as the RF switch 311 configured in the signal selector 204 of the signal converter 103 selectively switches the forward signal and the reflected wave signal to output the down converter, the down converter 205 is digital. The signal is converted into a signal and input to the signal detector 304 of the signal characteristic converter 201. When the signal detector 304 detects the strength of the power of the forward signal and the reflected wave signal and inputs it to the controller 206, the controller 206 calculates the standing wave ratio of the forward signal and the reflected wave signal to detect the standing wave ratio (S2). ).

Thereafter, the controller 106 controls the time delay 301, the variable attenuator 302, and the phase shifter 303 of the signal characteristic converter 201 according to the standing wave ratio, and the amplitude, phase, and Match the time delay (S3).

After inputting the output signals changed by the S3 process to the combiner unit 3 and determining whether the reflected wave signal is input, if the reflected wave signal is input, the process moves to the step S1 to repeat the process and the reflected wave signal is If not inputted, the process ends (S4).

The present invention described above improves the combiner performance by matching the amplitude, phase, and time delay of the input signals of the combiner when the output power of the transmission signal is increased using a combiner in a high frequency transmitter such as a base station. Provide effect.

In addition, as described above, by improving the combine performance of the combiner, the reflected wave signal reflected from the combiner can be removed, thereby providing an effect of extending the life of the high frequency transmitter.

Claims (7)

A signal characteristic converter for controlling the amplitude, phase, and time delay of the input signal and outputting the detected signal; A predistortion unit for predistorting and outputting the output signal of the signal characteristic conversion unit; An up-converter unit for converting the output signal of the predistortion unit into digital analog and then adjusting the frequency upward to output an RF signal; A signal selector for dividing the signal output from the up-converter and separating the split signal and the reflected wave signal input from the outside; A down converter for outputting the divided signal output from the signal selector and the reflected wave signal to the signal characteristic converter and the predistorter after analog-to-digital conversion; And a control unit for outputting a control signal for the amplitude, phase, and time delay to the signal characteristic converting unit according to the characteristic information of the reflected wave signal output from the signal characteristic converting unit. converter. The method of claim 1, wherein the signal characteristic conversion unit, A time delay unit for adjusting a time delay of the input signal under control of the controller; A variable attenuator for controlling the amplitude of the input signal under the control of the controller; A phase shifter for controlling the phase of the input signal under the control of the controller; And a signal detector for detecting a characteristic of the digital reflected wave signal inputted from the down converter. The method of claim 1, wherein the signal selector, A coupler for dividing and outputting the output RF signal of the upconverter; A circulator for outputting the RF signal output from the coupler to the outside and dividing and outputting the reflected wave signal input from the outside; And a switch which is switched under the control of the controller to selectively switch the reflected wave signals output from the coupler and the circulator and output the signal to the down converter. The method of claim 1, wherein the signal selector, A coupler for dividing and outputting the output RF signal of the upconverter; A fixed attenuator for attenuating and outputting the divided RF signal output from the coupler; A circulator for outputting the RF signal output from the coupler to the outside and dividing and outputting the reflected wave signal input from the outside; A second fixed attenuator configured to attenuate and output the reflected wave signal output from the circulator; A switch which is switched under the control of the controller to selectively switch an RF signal of the first fixed attenuator and a reflected wave signal output from the second fixed attenuator and output the signal to the down converter; Signal Transducer of Signal Transmitter. A high frequency signal transmitter having at least one signal converter for converting and outputting at least one signal input to a combiner, A signal detection process of detecting, by each of the signal characteristic converters, at least one signal input to a combiner and a reflected wave signal reflected from the combiner; A standing wave ratio detection step of detecting a standing wave ratio of the signal detected in the signal detection step; And a signal conversion process of controlling an input signal of the signal converter by using the standing wave ratio detected in the standing wave ratio detection process. 2. The method of claim 5, wherein the signal conversion process, Combined performance of the high frequency signal transmitter further comprises a feedback signal conversion process of returning to the signal detection process and repeating the process if the reflected wave signal is detected again from the combiner after the signal conversion process. How to improve. The method of claim 5 or 6, wherein the signal conversion process, And controlling the amplitude, phase, and time delay of the signal input to the signal characteristic converter to match the amplitude, phase, and time delay of the output signal of the signal characteristic converter.

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