KR20050080766A - Auto attenuation control method in rf inspection system - Google Patents

Abstract

An RF waveform monitoring apparatus for a mobile communication base station and repeater is disclosed. The present invention relates to an RF waveform monitoring apparatus for a mobile communication base station and a repeater for performing signal analysis using a spectrum analyzer and displaying the present invention. The RF waveform monitoring apparatus for a mobile communication base station and repeater according to the present invention relates to an input RF signal. The power detection is performed, and the attenuation unit for adjusting the resistance value based on the detected signal level is provided in front of the IF stage. According to the present invention, it is possible to prevent the malfunction of the equipment and maintain the stability of the equipment.

Description

Rf waveform monitoring device for mobile communication base station and repeater {Auto Attenuation Control Method in RF Inspection System}

The present invention relates to an RF waveform monitoring apparatus for a mobile communication base station and repeater, and more particularly, to an RF waveform monitoring apparatus for a mobile communication base station and repeater for monitoring forward and reverse RF waveforms of the mobile communication base station and repeater.

Currently, a base station and a repeater are widely used to connect a communication path of a wireless section in a mobile phone system.

The number of base stations and repeaters exceeds thousands, and in this situation, remote monitoring and control is essential for efficient operation of the base stations and repeaters. This remote monitoring and control function has evolved from the monitoring of device alarm and output state of the equipment to the waveform transmitted / received.

1 is a diagram illustrating a connection relationship between a base station and a high power repeater of a conventional RF waveform monitoring apparatus. As shown in Fig. 1, the main antenna 1, a filter (duplexer) 2, a low power amplifier (LPA) 3, a low noise amplifier (LNA) 4, and an up / down converter (Up / Down Converter (5), a diversity antenna (6), a filter (SIP) 7, and an LNA 8 are further provided. In this configuration, the forward RF power is measured by coupling (Coupling) at the coupler 9 provided at the rear of the filter of the equipment. On the other hand, the reverse RF power is measured by coupling (Coupling) in the coupler 10 provided at the rear end of the receiving LNA of the equipment. This coupled signal is passed to the optical repeater RF monitoring port 11.

2 is a diagram illustrating a configuration for analyzing an RF waveform in a general RF waveform monitoring apparatus. It has an algorithm similar to that of a typical spectrum analyzer.

As shown in FIG. 2, the configuration for analyzing an RF waveform includes a filter 21, an amplifier 22, a mixer 23, a local oscillator 24, a surface acoustic wave (SAW) filter 25, and A /. D converter 26.

The signal input to the RF waveform monitoring device passes through the filter 21 and then amplified by a certain amount using the amplifier AMP 22 and sent to the mixer 23.

At the mixer 23 stage, the signal is converted to an intermediate frequency by the local frequency and then input to the SAW filter 25. At this time, the bandwidth BW of the SAW filter 25 is variable, but is usually fixed to 30 kHz.

A signal other than the desired signal is removed with RBW (B.W = 30 ms), and the A / D conversion is performed after detecting the signal level.

At this time, after detecting the signal level (Detect), the first stage attenuation amount ATT is changed in accordance with the signal level.

Sweeping the local frequency also has the effect of sweeping the frequency passing through the SAW filter.

For example, a signal of 2130 MHz is analyzed while the frequency of the input signal is 2130 to 2150 MHz, the local frequency is 1950 to 1970 MHz, and the pass band of the SAW filter 25 is 79.985 to 80.015 MHz. In this case, the local frequency is converted to an intermediate frequency (IF) at 80 MHz using 1950, and when the 2131 MHz signal is analyzed, the local frequency is converted to 80 MHz using 1910 (IF). Convert to frequency. Repeat the above steps to analyze the waveform.

The monitoring frequency and the band frequency of the RF waveform monitoring device may vary. For example, the Tx band monitorable frequency of the WCDMA RF waveform monitor is 2105 MHz to 2175 MHz, and the user can monitor any frequency band band within the monitorable frequency.

In the current RF waveform monitoring device, if an appropriate frequency is set on the graphical user interface (GUI), it operates normally. However, the following obstacle may occur when the frequency is changed.

When observing the Spectrum screen by setting a specific band (Frequency) and duration (SPAN) on the GUI of the RF waveform monitoring device, the frequency of the signal is 2132.5. Assuming that a signal exists at MHz (BW = 5MHz), and the frequency setting of the RF waveform monitoring device is to monitor the frequency band of 2140 to 2150 MHz, the first ATT is set to the minimum because there is no input signal in the set band area. .

At this time, when high power RF signal flows out of the set band region, saturation occurs in the amplifier AMP 22 and the mixer 23 at the rear end of the attenuator ATT, and thus the spectrum display of the GUI Saturated waveforms appear on the display instead of the actual ones, which can cause confusion for the operator. In addition, damage may occur to the device due to excessive input of the amplifier AMP 22 and the mixer 23.

The present invention is to solve the above problems, an object of the present invention is to monitor the RF waveform of the mobile communication base station and repeater to monitor and control the forward and reverse RF waveform of the mobile communication base station and repeater in order to prevent equipment malfunction and maintain stability To provide a device.

The present invention relates to an RF waveform monitoring apparatus for a mobile communication base station and a repeater for performing a signal analysis using a spectrum analyzer and displaying the same, as the technical idea for achieving the object of the present invention. The RF waveform monitoring device is characterized in that the attenuator for adjusting the resistance value based on the detected signal level by performing a power detection on the input RF signal, characterized in that made in front of the IF stage. At this time, the attenuation unit, the detection unit for detecting the power of the RF signal; A controller comparing the signal output from the detector with a preset signal and outputting a control signal according to a comparison result; And a variable resistor for changing the resistance value by the control signal.

Specifically, the RF waveform monitoring apparatus of the mobile communication base station and the repeater of the present invention, the detection unit for detecting the power of the RF signal, and compares the signal output from the detection unit with a preset signal, and outputs a control signal according to the comparison result An attenuator comprising: a control unit configured to control the resistance; An amplifier for amplifying the RF signal controlled by the attenuator; A local oscillator for generating an oscillation signal for converting the RF signal into an IF signal; A mixer for converting the RF signal output from the amplifier into an IF signal of a predetermined band according to a local oscillation signal provided from a local oscillator, and amplifying and outputting the converted signal; A filter unit for filtering and outputting only a signal corresponding to a set bandwidth among the IF signals; And an A / D converter for performing signal conversion to digitally process the filtered signal.

At this time, the filter unit uses a SAW filter.

Hereinafter, with reference to the accompanying drawings, the configuration and operation of the embodiment of the present invention will be described in detail.

3 is a diagram illustrating an RF waveform monitoring apparatus for a mobile communication base station and a repeater according to an embodiment of the present invention. As shown in FIG. 3, the RF waveform monitoring apparatus of the present invention includes an attenuation unit 30, an amplifier 40, a mixer 50, a local oscillator 60, a filter unit 70, and an A / D converter 80. ).

First, the attenuator 30 includes a variable resistor 301 and a controller 302, and performs a function of adjusting the value of the variable resistor 301 by checking a level of an input RF signal. As a feature of the present invention, the attenuator 30 is formed at the front end of the amplifier 40, that is, the RF signal is input, and the control unit 302 adjusts the value of the variable resistor 301.

Here, in contrast to the conventional RF waveform monitoring apparatus, the conventional RF waveform monitoring apparatus performs power detection at the IF stage, but the proposed algorithm in the present embodiment detects power from the RF signal at the first stage. Perform (Power Detection). This enables full-band signal detection. That is, the attenuator 30 is controlled based on the sensed signal level.

The amplifier 40 amplifies the RF signal controlled by the attenuator 30.

The mixer 50 converts the RF signal output from the amplifier 40 into an IF signal of a predetermined band according to the local oscillation signal provided from the local oscillator 60, and amplifies and outputs the converted signal.

The filter unit 70 filters and outputs only a signal corresponding to a set bandwidth among the input IF signals. The bandwidth of the IF filter unit 70 is determined according to the minimum frequency of the signal to be analyzed. A crystal filter and a surface acoustic wave (SAW) filter are used for the filter unit 70, and a selection switch for selecting such a filter (not shown), a patching unit (not shown) for input / output signals, and the like are further included. It may include.

As such, since the attenuator 30 is positioned at the first stage, the attenuation unit 30 may operate regardless of the sweep of the band set on the GUI, thereby minimizing saturation on the device protection and spectrum screens.

Although not shown, a microprocessor may be connected between the A / D converter and the local oscillator, and the microprocessor may further include an RF switch, a power relay, and a warning unit.

The operation of the RF waveform monitoring device of the present invention configured as described above will be described.

In the state of bidirectional communication, the level is detected for the input RF signal. The power intensity of the detected signal is input to the controller 302, and the controller 302 determines whether the power intensity exists within a preset range. If the power intensity is within the range, it is determined to be normal. On the other hand, when it is determined that the power intensity is out of the setting range, the controller 302 adjusts the variable resistor 301 value. This outputs a value in which the power strength of the signal is adjusted.

Thereafter, the amplifier AMP 40 is used to amplify a predetermined amount and send the mixer 50 to the mixer 50.

Meanwhile, the local oscillator 60 generates an oscillation signal for converting the RF signal into the IF signal and supplies it to the mixer 50.

Accordingly, the signal is converted into an intermediate frequency (IF) by the local frequency at the mixer 50 and then input to the SAW filter 70. At this time, the bandwidth BW of the SAW filter 70 is variable, but is usually fixed to 30 kHz.

A signal other than the desired signal is removed with RBW (B.W = 30 ms), and the analog / digital conversion is performed by the A / D converter 80 after detecting the signal level. Thereafter, it is transmitted to a microprocessor (not shown) for signal processing.

The above process, that is, the monitoring of the RF waveform is repeatedly performed while changing the band.

The present invention is not limited to the above-described embodiments, and it will be apparent that many modifications are possible by those skilled in the art within the technical spirit of the present invention.

As described above, the RF waveform monitoring apparatus of the mobile communication base station and repeater according to the present invention operates by irrespective of the sweep of the band set on the GUI by controlling the attenuation unit based on the signal level detected at the front end of the IF stage, thereby protecting the device and spectrum ) Saturation on the screen can be minimized. That is, it is possible to prevent the malfunction of the equipment and maintain the stability of the equipment.

1 is a view showing a connection relationship between a base station and a high power repeater of a conventional RF waveform monitoring device;

2 is a diagram illustrating a configuration for analyzing an RF waveform in a general RF waveform monitoring apparatus;

3 is a diagram illustrating an RF waveform monitoring apparatus for a mobile communication base station and a repeater according to an embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

30: attenuation part

301: variable resistor 302: control unit

40: amplifier 50: mixer

60: local oscillator 70: filter unit

80: A / D Converter

Claims (4)

In the RF waveform monitoring apparatus of the mobile communication base station and repeater performing signal analysis using a spectrum analyzer, RF waveform monitoring device for a mobile communication base station and repeater, characterized in that by performing a power detection on the input RF signal, the attenuation unit for adjusting the resistance value based on the detected signal level is provided in front of the IF stage. The method of claim 1, wherein the attenuation unit, A detector for detecting power of an RF signal; A controller comparing the signal output from the detector with a preset signal and outputting a control signal according to a comparison result; And Variable resistor to change the resistance value by the control signal RF waveform monitoring device for a mobile communication base station and repeater, comprising a. A detector for detecting the power of the RF signal, a controller for comparing the signal output from the detector with a preset signal, and outputting a control signal according to a comparison result, and a variable resistor for changing the resistance value by the control signal. Attenuating section; An amplifier for amplifying the RF signal controlled by the attenuator; A local oscillator for generating an oscillation signal for converting the RF signal into an IF signal; A mixer for converting the RF signal output from the amplifier into an IF signal of a predetermined band according to a local oscillation signal provided from a local oscillator, and amplifying and outputting the converted signal; A filter unit for filtering and outputting only a signal corresponding to a set bandwidth among the IF signals; And A / D converter performing signal conversion to digitally process the filtered signal RF waveform monitoring device for a mobile communication base station and repeater, comprising a. [4] The RF waveform monitoring apparatus of claim 3, wherein the filter unit is a SAW filter.