JPH09275379A - Method and device for measuring adjacent channel leakage power - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure an adjacent channel leakage power of a transmitter at a high dynamic level by providing an arithmetic unit used to control amplification of a signal of a normal system to measure a carrier power and a signal of a notch system amplifying a signal at a detuned frequency band other than the carrier frequency. SOLUTION: An arithmetic unit 18 controls switches 11A, 11B to the position of an amplifier 12 to receive an input signal of a normal system. The input signal is optimizingly amplified by the amplifier 12 and the optimized input level is given to an A/D converter 15. Then the switches 11A, 11B are thrown to the position of the notch system. The input level of the input signal is optimized by an amplifier 13 and given to a band limit filter 14, in which a carrier frequency band signal is blocked and the resulting signal is fed to an A/D converter 15. The digital signal obtained by the A/D converter 15 is stored in a waveform memory 16. Then a correction value obtained in the case of arithmetic operation of the normal system is taken into acount and the arithmetic unit 18 executes Fourier transformation similarly to the case with the signal of the normal system so as to measure the adjacent channel leakage power at the deturned frequency band.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly dynamic adjacent channel leakage power measuring method and apparatus in a digital wireless communication system.

[0002]

2. Description of the Related Art In recent years, PHS (second generation cordless telephone system) has been used as a digital communication system in Japan.
PDC (Digital Car Phone System) is becoming mainstream, and in the field of measuring instruments, development of highly accurate measuring instruments corresponding to the digital communication system is required in a timely manner.

The conventional adjacent channel leakage power measurement will be described below. FIG. 4 is a block diagram showing a configuration of a conventional adjacent channel leakage power measuring device. An amplifier circuit 42 for receiving an input signal from the input terminal 41 and setting it to an appropriate level, an A / D converter 43 for converting an analog signal into a digital signal, and a waveform memory 44 for storing the converted data. An arithmetic unit 45 for performing an arithmetic operation from the stored waveform memory 44 with a digital signal,
And a calculation memory 46 for storing the calculation result.

The operation in the case of the above configuration will be described below. An A / D converter 43 for converting an analog signal into a digital signal is used in order to receive an input signal from the input end and perform an operation in an arithmetic unit. The digitally converted signal is taken into the waveform memory 44 and transferred to the arithmetic memory 46. When the measurement is performed using the arithmetic unit 45, the A / D converter 43 is usually used. A / D
If the converter 43 has a 12-bit resolution, it has about 68 dB as a dynamic range to be compensated by itself. However, the digital communication system requires a measuring capability of 67 dB or more as a measuring instrument including a transmission allowable error.

[0005]

However, in the above-mentioned conventional configuration, the dynamic range of the A / D converter is limited, so that it is difficult to measure the standard including the transmission allowable error with high dynamics. Met.

The present invention solves the above-mentioned conventional problems by providing an adjacent channel leakage power measuring method and apparatus capable of ensuring a high dynamic range while using an A / D converter having an equivalent conventional dynamic range. The purpose is to provide.

[0007]

In order to achieve the above object, the present invention measures carrier power in a normal system in which a frequency band to be measured is allowed to pass flatly to block the carrier band and to set a detuning frequency band. A configuration in which the detuning frequency band power is measured by an amplifying notch system, and the adjacent channel leakage power is calculated by the carrier power measured in the normal system and the detuning frequency band power amplified in the notch system. Is.

As described above, the carrier wave power that is effective in the normal system and the detuning frequency power that is effective in the notch system are respectively Fourier-transformed (hereinafter referred to as FFT) by the arithmetic unit. By synthesizing by combining, it becomes possible to measure beyond the dynamic range limited by the A / D converter.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a digital radio communication system, in which the carrier power is measured by a normal system that passes the frequency band to be measured flat, and the carrier band is blocked. The detuning frequency band power is measured by the notch system that amplifies the detuning frequency band, and the adjacent channel leakage power is calculated from the carrier power measured in the normal system and the detuning frequency band power amplified in the notch system. This has the effect that a low-level signal hidden by internal noise in the device can be measured from the results stored in the normal type and notch type arithmetic memories.

Further, the invention according to claim 2 is a switch means for switching between a carrier frequency band and a detuning frequency band system of an input signal, an amplifier for optimizing the level of the carrier frequency band, and the carrier frequency band. A band limiting filter for attenuating the detuning frequency band, an amplifier for amplifying the detuning frequency band, and an A / D converter for converting an analog signal into a digital signal, and the system of the input signal is switched by the switch means to set the carrier power value. And the adjacent channel leakage power value are calculated, which has the effect of enabling measurement beyond the dynamic range limited by the A / D converter.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a block diagram showing a configuration of an adjacent channel leakage power measuring apparatus according to the present embodiment. In FIG. 1, 11A and 11B are switches for switching input signals, which are controlled by a control signal from an arithmetic unit 18 described later. Reference numeral 12 is an amplifier for optimizing the input level of an A / D converter 15, which will be described later, at the time of taking in the normal system, and 13 is A / D at the time of taking in the notch system.
This is an amplifier that adjusts the level of the converter 15 to an appropriate level. 1
Reference numeral 4 is a band limiting filter that blocks the carrier frequency band when the notch system is taken in. Reference numeral 15 is an A / D converter for converting normal type and notch type analog signals into digital signals, and 16 is a waveform memory for storing the digitally converted signals. Reference numeral 17 denotes an arithmetic memory that stores the arithmetic result of the arithmetic unit 18.
And an arithmetic unit 18 for executing the arithmetic constitute an arithmetic block.

FIG. 2 shows frequency characteristics of the A / D converter 15 shown in FIG. In FIG. 2, reference numeral 21 is a normal frequency characteristic, and 22 is a notch frequency characteristic. 23A, 23B, 23C, and 23D indicate adjacent channel leakage power measurement frequency bands set by the standard.
4A, 24B, 24C, and 24D indicate the expansion level of the notch dynamic range with respect to the normal frequency characteristic. For this level, the frequency characteristic of the normal system is calculated from the level difference of each system by a method of varying the frequency in advance in a required frequency band from a signal generator (hereinafter referred to as SG).
And the frequency characteristic 22 of the notch system are measured. The value calculated here is stored in advance in the calculation memory 17 as a correction value.

The operation of the above embodiment will be described below with reference to the flowchart of FIG. The switch 11 is operated by the arithmetic unit 18 to capture a normal input signal.
A and 11B are controlled to the amplifier 12 side. The input signal is
The input level is optimized by the amplifier 12 for A / D
It is applied to the converter 15. A / D with A / D converter 15
The converted digital signal is stored in the waveform memory 16. The arithmetic unit 18 reads the digital signal from the waveform memory 16, executes the Fourier transform (FFT), calculates the carrier power of the waveform that has been taken in, and stores it in the arithmetic memory 17.

Next, switches 11A and 11B are added to the notch system.
Switch. After the input level of the input signal is optimized by the amplifier 13, the carrier frequency band is blocked by the band limiting filter 14 and applied to the A / D converter 15. The digital signal A / D converted by the A / D converter 15 is stored in the waveform memory 16. In consideration of the correction value obtained in the normal system calculation, the calculation device 1
8, the FFT is executed in the same manner as the normal system, and the adjacent channel leakage power in the detuning frequency band is measured. This enables measurement beyond the dynamic range of the A / D converter 15.

As described above, according to the above embodiment,
By switching and measuring the normal system that captures the carrier power and the notch system that blocks the carrier frequency band by a band elimination filter and amplifies the adjacent tone frequency band and captures the carrier power and the notch The detuning frequency power validated by the system is combined by the calculation device using the FFT measurement results, which enables measurement beyond the dynamic range limited by the A / D converter. It has a configuration that realizes measurement of low level signals hidden in internal noise.

[0016]

As described above, according to the present invention, the normal system for measuring the carrier power and the carrier frequency band are attenuated by the band limiting filter, and the other detuned frequency bands are amplified, and the device A notch system that amplifies low-level signals hidden in the internal noise of the system is constructed, and the measurement results of each system are calculated by a calculation device to measure the dynamic range limited by the A / D converter. It has the effect of being able to.

[Brief description of drawings]

FIG. 1 is a block diagram of an adjacent channel leakage power measuring device according to an embodiment of the present invention.

FIG. 2 is a frequency characteristic diagram in the same embodiment.

FIG. 3 is a flowchart showing an operation in the same embodiment.

FIG. 4 is a block diagram of a conventional adjacent channel leakage power measuring device.

[Explanation of symbols]

 11A, 11B switch 12 amplifier 13 amplifier 14 band limiting filter 15 A / D converter 16 waveform memory 17 arithmetic memory 18 arithmetic unit

Claims (2)

[Claims] 1. In a digital wireless communication system, a detuning frequency is measured by a notch system that measures carrier power in a normal system that passes the frequency band to be measured flatly and that blocks the carrier band and amplifies the detuning frequency band. Measure the power
An adjacent channel leakage power measuring method is characterized in that an adjacent channel leakage power is calculated from the carrier power measured in the normal system and the detuning frequency band power amplified in the notch system. 2. A switch means for switching between a carrier frequency band and a detuning frequency band system of an input signal, an amplifier for optimizing the level of the carrier frequency band, a band limiting filter for attenuating the carrier frequency band, and An amplifier for amplifying the detuning frequency band and an A / D converter for converting an analog signal into a digital signal are provided, and the input signal system is switched by the switch means to calculate the carrier power value and the adjacent channel leakage power value. An adjacent channel leakage power measuring device characterized by: