KR100800719B1 - Apparatus for measuring code division multiple access signal - Google Patents

Abstract

The present invention relates to an apparatus for measuring code division multiple access signals, and more particularly, to an apparatus for measuring CDMA signals in consideration of effects of PAR and temperature.

The apparatus for measuring a code division multiple access signal according to the present invention includes a plurality of detectors including first to third detectors, the code division multiple access signal, and code division multiplexing. A signal switching unit which receives a continuous waveform signal of an access frequency band and outputs one of the code division multiple access signal and the continuous waveform signal according to a control signal of a signal switching unit, amplifies a signal output from the signal switching unit, and A first amplifying and filtering unit for filtering, a second amplifying and filtering unit for amplifying and filtering the signal output from the signal switching unit and outputting the third detector, and a signal output from the first amplifying and filtering unit The extracted intermediate frequency signal is attenuated according to the variable attenuator control signal, and the attenuated intermediate frequency signal is first and second. A variable attenuator output to a second detector, a variable attenuator based on the measured value of the first detector, and a control unit of the signal switching unit to control the code division multiple access signal and the continuous waveform signal to the first through third And selectively provided to a detector and receiving a measured value of the code division multiple access signal and a measured value of the continuous waveform signal from at least one of the first to third detectors, based on the measured value of the continuous waveform signal. And a controller for correcting the measured value of the code division multiple access signal.

Through the measuring method of the present invention as described above, the gain change of the main pass can be corrected even in a situation in which the temperature and the PAR are unknown. In addition, it is possible to correct the influence of the temperature change (gain change in the main path, the temperature characteristic of the detector) and the influence by the PAR.

Code Division Multiple Access (CDMA), Temperature, Peak Power to Average Power Ratio (PAR)

Description

Code Division Multiple Access Signal Measuring Equipment {APPARATUS FOR MEASURING CODE DIVISION MULTIPLE ACCESS SIGNAL}             

1 is a block diagram illustrating an apparatus for measuring code division multiple access signals according to a preferred embodiment of the present invention.

The present invention relates to an apparatus for measuring code division multiple access (CDMA) signals, and in particular, a CDMA signal considering the effects of peak power to average power ratio (PAR) and temperature. It relates to a measuring device.

Digital transmission has many advantages over analog transmission. Therefore, digitalization is progressing in almost all fields such as CDMA method of mobile communication, wireless data transmission, satellite broadcasting and terrestrial broadcasting, and wireless subscriber network.

In order to measure the performance of the base station transmitter and subscriber station transmitter used in the wireless subscriber network, it is recommended to measure a number of items, including aerial power, frequency tolerance, occupied frequency bandwidth, and code domain power. have.

In the case where the transmitter measures the total RF output power, the total power is mean power delivered to a load having a resistance equal to the transmitter's normal load impedance. The output of the transmitter is an important factor in determining system capacity, coverage, and signal quality. If the output of the base station transmitter falls below the minimum output level for coverage, coverage is reduced and the call is dropped. On the other hand, if the output level is higher than the coverage level, the interference caused by pilot pollution (receiving three or more pilot signals) results in system capacity reduction and signal quality degradation. In addition, in the CDMA method, it is not possible to determine whether the system is operating normally by simply measuring the total output of the base station, and it is necessary to measure the output for each code region (that is, for each channel). In other words, the CDMA scheme that separates channels through code modulation requires new measurement techniques such as signal analysis for code domains rather than time or frequency domains. By analyzing the power for each code to determine whether various codes are operating normally, the capacity of the sector of the base station can be maximized and used.

Measurement items as described above can be measured using a spectrum analyzer. The value measured by the general spectrum analyzer measurement method should be corrected for crest factor. A common method for measuring the power of a CDMA signal is to use a filter and a power detector to filter signals of a particular band. However, conventional devices using power detectors have many limitations for implementation on a printed circuit board (PCB). For example, the size is limited, which limits the type of power detector that can be used. In addition, it is often difficult to control the temperature because it is installed in a specific measurement equipment, and in consideration of fast response time and dynamic range, it is necessary to use a detector having an error due to PAR. Changing the gain on the path with temperature is also a factor of error, and the temperature characteristic of the power detector also affects accuracy.

Accordingly, the present invention provides a CDMA signal measuring apparatus that can more accurately measure the power of the CDMA signal when temperature control is impossible.

In addition, the present invention provides a CDMA signal measuring apparatus for increasing the accuracy of the power detector in a situation in which the PAR of the signal to be measured is not recognized.

The apparatus for measuring a code division multiple access signal according to the present invention includes a plurality of detectors including first to third detectors, the code division multiple access signal, and code division multiplexing. A signal switching unit which receives a continuous waveform signal of an access frequency band and outputs one of the code division multiple access signal and the continuous waveform signal according to a control signal of a signal switching unit, amplifies a signal output from the signal switching unit, and A first amplifying and filtering unit for filtering, a second amplifying and filtering unit for amplifying and filtering the signal output from the signal switching unit and outputting the third detector, and a signal output from the first amplifying and filtering unit The extracted intermediate frequency signal is attenuated according to the variable attenuator control signal, and the attenuated intermediate frequency signal is first and second. A variable attenuator output to a second detector, a variable attenuator based on the measured value of the first detector, and a control unit of the signal switching unit to control the code division multiple access signal and the continuous waveform signal to the first through third And selectively provided to a detector and receiving a measured value of the code division multiple access signal and a measured value of the continuous waveform signal from at least one of the first to third detectors, based on the measured value of the continuous waveform signal. And a controller for correcting the measured value of the code division multiple access signal.

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DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings in which: FIG. It should be noted, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth, which are intended to be illustrative, and to fully convey the scope of the invention to those skilled in the art. . In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the gist of the present invention have been omitted, and it should be noted that components that perform the same functions as those of the above-described drawings will be described with the same reference numerals.

As will be appreciated by those skilled in the art, the present invention can be implemented in products such as methods and roaming control devices in a mobile communication network. Therefore, the present invention may have a completely hardware implementation, a software implementation, or an implementation form combining software and hardware features, which will be described below with reference to the accompanying drawings.

1 is a block diagram of an apparatus for measuring code division multiple access signals according to a preferred embodiment of the present invention.

The reference oscillator 12 oscillates a predetermined CW signal. The CW signal output from the reference oscillator 12 is input to another terminal of the first switch 14 through which a CDMA signal having a crest factor is input to one side. The signal switching unit includes a first switch 14 and a second switch 16. The signal switching unit inputs the oscillated continuous waveform signal and the code division multiple access, and transmits the two input signals to at least one of the first and second output ports in response to a predetermined control. Optionally output through one. Referring to FIG. 1, the first switch 14 selects one of the CDMA signal and the CW signal by a switching control signal output from the controller 36 to be described later and supplies it to the input terminal of the second switch 16 connected to the output terminal.

The first RF amplifier / filter unit 18 and the second RF amplifier / filter unit 22 are connected to the first and second output ports of the signal switching unit, that is, two output terminals of the second switch 16. The first RF amplifier / filter unit 18 RF amplifies and filters the input continuous waveform signal or the code division multiple access signal, respectively, and supplies the same to the third detector 20 located on the first path. The second RF amplifier and filter unit 22 supplies the first and second detectors 34 and 32 located on the second path.

The mixer 24 is connected to an output terminal of the second RF amplifier and filter unit 22, and outputs a down-converted signal by mixing a signal output from the second RF amplifier / filter unit and a preset local oscillation frequency.

The intermediate frequency part 26 is called an IF unit. The intermediate frequency part 26 filters the down-converted signal by the mixer 24 and outputs an intermediate frequency.

The variable attenuator 28 down-converts the signal output from the second RF amplifier and the filter unit 22 to extract a signal of an intermediate frequency band, and attenuates the output power level of the extracted intermediate frequency corresponding to an input of a control signal. Supply on the input path.

A two-way divider 30 is connected between the variable attenuator 28 and the input terminals of the first and second detectors 34 and 32 to distribute the damped controlled intermediate frequency to the inputs of the first and second detectors 34 and 32. do.

The controller 36 adjusts the attenuation value of the variable attenuator 28 so as to be in an optimum measurement range due to the dynamic range difference between the first and second detectors 34 and 32, and selectively controls the signal switching unit to perform the code division multiple access. A signal is provided to the first, second and third detectors 34, 32, and 20 on the first, second, and third paths to calculate detection values output therefrom, and converting the continuous waveform signal into the first, second, and third paths. The second, third, and third detectors 34, 32, and 20 are used as output values therefrom to calculate the temperature, PAR, and gain of the calculated code division multiple access signal.

The first detector 34 and the third detector 20 use a high accuracy and a large dynamic range for the CW signal. The second detector 32 uses a relatively small error with respect to the PAR, such as an RMS detector.

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The Pow function matches the detector's characteristic value to the signal at the input port. C0 is the PAR value for the CW signal. att is an attenuation value set on the main path. att_ref is the attenuation value set as a reference when measuring. VA, VB, and VC are the output voltages of the first detector 34, the second detector 32, and the third detector 20. C is a variable representing PAR and T is a temperature index.

1) CW, T = T0 (at room temperature)

   Pow_A (T0, C0, att_ref, VA), Pow_B (T0, C0, att_ref, VB) and Pow_C (T0, C0, VC) are obtained.

2) Obtain ∂Pow_C / ∂T for CW.

3) centering on CW, att_ref

   Find ∂Pow_A / ∂T and ∂Pow_B / ∂T.

4) Measure Pow_A (T0, C, att_ref, VA), Pow_B (T0, C, att_ref, VB) by changing PAR at T = T0, att_ref. However, it is difficult to obtain Pow_A and Pow_B data sets by actually changing PAR. In this case, the variable C representing the PAR may be a variable that exactly depends on the PAR. However, Pow_A and Pow_B should be monotonic functions for variable C.

[Measurement and measured value calculation]

For convenience, the signal size, gain, and the like are represented on a logarithm scale.

1) A signal with an arbitrary crest factor comes in. At this time, the first switch 14 is connected to the signal input port.

Usually, the measuring dynamic range of the second detector 32 is small and the measuring dynamic range of the first detector 34 is large, so that the second detector 32 is the optimal measuring range based on the measured value of the first detector 34 for the current incoming signal. Adjust the value of variable attenuator 28 so that it can be measured at. When adjusting the attenuator value, ignore the effects of temperature or PAR.

2) When the first detector 34 and the second detector 32 measure, the output voltages VA1 and VB1 come out. Since the current temperature, gain variation, and PAR are not known, corrections are necessary.

3) Connect the first switch 14 to the reference oscillator 12. Then measure VA2 and VB2 and connect the second switch 16 to the third detector 20 to measure VC2.

4) ΔT is obtained from VA2 and VB2 as shown in Equation 1 below.                     

Where det_A and det_B represent the signal power at the input ports of the first detector 34 and the second detector 32, respectively.

Pow_A (T, C, att, VA) = G (T, C, att) + det_A (T, C, VA)

Pow_B (T, C, att, VB) = G (T, C, att) + det_B (T, C, VB)

det_A (T, C0, VA2) = det_B (T, C0, VB2)
Where G represents the gain value.

5) As shown in Equation 2, the magnitude of the reference signal measured by the third detector 20 in ΔT and VC2 is obtained.

6) For the gain correction, calculate the following values using △ T and VA2 as shown in <Equation 3>.                     

7) The gain correction value ΔG due to the attenuation value change in the main path is obtained as follows. ΔG ~ Pow_C (T, C0, VC2) -Pow_A (T0, C0, att_ref, VA1)

There may be an effect of gain due to PAR change in the main pass, but the effect can be ignored by designing to operate in a linearizable area.

8) Using? T, VA1, and VB1,? C is obtained as shown in Equation 4 below.

9) Obtain the measured value whose temperature, PAR, and gain change are corrected as in <Equation 5>.                     

Although the above-described example has been described with reference to one embodiment, it will be understood by those skilled in the art that the above-described example is only intended to illustrate the present invention, not to limit the scope of the present invention. These examples can be modified in a number of different ways having the advantages of the present invention.

While the preferred embodiments of the invention have been disclosed in the drawings, detailed description, and examples, and specific concepts have been used, these concepts are not intended to limit the invention, and the scope of the invention is defined in the appended claims and their respective elements. It should be defined by the equivalent.

Through the measuring method of the present invention as described above, the gain change of the main pass can be corrected even in a situation in which the temperature and the PAR are unknown. In addition, it is possible to correct the influence of the temperature change (gain change in the main path, the temperature characteristic of the detector) and the influence by the PAR.

Claims (4)

An apparatus for measuring a code division multiple access signal, A plurality of detectors including first to third detectors, A signal switching unit which receives the code division multiple access signal and the continuous waveform signal of the code division multiple access frequency band and outputs one of the code division multiple access signal and the continuous waveform signal according to a signal switching unit control signal; A first amplifier and filter unit for amplifying and filtering a signal output from the signal switching unit; A second amplifying and filtering unit amplifying and filtering the signal output from the signal switching unit and outputting the filtered signal to the third detector; A variable attenuator configured to attenuate an intermediate frequency signal extracted from the signal output from the first amplification and filter unit according to a variable attenuator control signal, and to output the attenuated intermediate frequency signal to the first and second detectors; The variable attenuator is controlled based on the measured value of the first detector, and the signal switching unit is controlled to selectively provide the code division multiple access signal and the continuous waveform signal to the first to third detectors. Receiving the measured value of the coded multiple access signal and the measured value of the continuous waveform signal from at least one of the first to third detectors, the measurement of the coded multiplex signal based on the measured value of the continuous waveform signal Code division multiple access signal measuring apparatus comprising a controller for correcting a value. The method of claim 1, A mixer for mixing a signal output from the first amplifying and filtering unit with a preset local oscillation frequency to output a down-converted signal; And an intermediate frequency unit configured to filter the down-converted signal output from the mixer and output the intermediate frequency signal to the variable attenuator. The method of claim 1, The controller, And a code division multiple access signal measuring apparatus for controlling the variable attenuator so that the second detector operates in an optimum measuring range based on the measured value of the first detector. The method of claim 1, The controller, And a code division multiple access signal measuring device configured to correct a temperature, a peak power to average power ratio (PAR), and a change in gain of the measured value of the code division multiple access signal.

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