JP2783740B2 - Adjacent channel leakage power measurement method with filter correction processing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring adjacent channel leakage power using a spectrum analyzer.

[0002]

2. Description of the Related Art Conventionally, adjacent channel leakage power is measured by displaying power of a specified bandwidth BS separated from a reference carrier by a channel interval CHSP set by a user as shown in FIG. , And by dividing them by the total power sum to derive the upper adjacent channel leakage power (ratio) and the lower adjacent channel leakage power (ratio).

[0003]

However, since a certain type of filter (such as a root Nyquist filter) is functioning in the transmitter / receiver, and the signal passed through the filter is received by the spectrum analyzer, The operation result obtained by the conventional method described above is only an approximate value.

It is an object of the present invention to accurately measure the adjacent channel leakage power of a signal transmitted through a filter,
An object of the present invention is to provide an adjacent channel leakage power measurement method with a filter correction process.

[0005]

According to the method for measuring adjacent channel leakage power with filter correction processing of the present invention, constants for calculating a frequency width and a channel interval from a carrier wave to upper and lower adjacent channels and a shape of the filter are set. Determining the height of the filter for each frequency point within the bandwidth defined by the frequency width and the channel interval as correction data; obtaining a total power sum from display waveform data; Weighting the display waveform data with the correction data, integrating the result to obtain the power sum of the lower adjacent channel, and weighting and correcting the display waveform data of the upper adjacent channel with the correction data. Summing to obtain the power sum of the upper adjacent channel; and summing the power of the lower adjacent channel. Calculating the lower adjacent channel leakage power and the upper adjacent channel leakage power by dividing the power sum of the upper adjacent channel by the total power; and displaying the lower adjacent channel leakage power and the upper adjacent channel leakage power. And steps.

[0006]

Since the sum of the powers of the lower and upper adjacent channels is obtained by adding correction suitable for the filter to the display waveform data, the adjacent channel leakage power can be accurately measured.

[0007]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a flowchart of an embodiment of a method for measuring adjacent channel leakage power with filter correction processing according to the present invention, and FIG. 2 is a diagram showing a shape of a root Nyquist filter.

First, a symbol rate (1 / T) and a roll factor (α) which are constants for calculating a frequency width, a channel interval from a carrier wave and upper and lower adjacent channels, and a filter shape are calculated from a panel key of a spectrum analyzer. Set (step 1). Next, the measurement execution key is pressed (step 2). Thereafter, the internal processing of the spectrum analyzer is performed. First, the input constant 1 / T,
Root Nyquist filter correction data is created from α in the form of a table (step 3). That is, the height H (f) of the root Nyquist filter for each point of the frequency f is obtained by the following equation.

[0010]

(Equation 1) Next, the total power sum is obtained from the display waveform data (step 4). Next, the display waveform data of the lower adjacent channel is
Weight correction is performed using the correction data created in step 2 (step 5). That is, the other waveform portions are weighted and corrected with the correction data so that the waveform data corresponding to H (f) = 1 becomes 100%. The corrected waveform data is integrated to obtain a power sum (step 6). Next, the same processing as in Steps 5 and 6 is performed for the upper adjacent channel, the display waveform data of the upper adjacent channel is weighted and corrected (Step 7), and the results are integrated to obtain the power sum (Step 8). Next, the power sum of the lower adjacent channel and the power sum of the upper adjacent channel obtained in steps 6 and 8 are divided by the total power obtained in step 4 to obtain the lower and upper adjacent channel leakage power (ratio ) Is calculated (step 9). Finally, the calculated lower and upper adjacent channel leakage power (ratio) is displayed on a display, and markers are displayed at the positions of the lower and upper adjacent channels (step 10).

By providing a filter table other than the root Nyquist filter inside the spectrum analyzer, it is possible to measure the adjacent channel leakage power more accurately for a wireless device incorporating another filter.

[0012]

The present invention described above has an effect that the accurate measurement of the adjacent channel leakage power is made possible by adding the correction suitable for the filter to the display waveform data of the adjacent channel.

[Brief description of the drawings]

FIG. 1 is a flowchart of an embodiment of a method for measuring adjacent channel leakage power with filter correction processing according to the present invention.

FIG. 2 is a diagram showing a shape of a root Nyquist filter.

FIG. 3 is a diagram illustrating a conventional adjacent channel leakage power measurement method.

[Explanation of symbols]

 1 to 10 steps

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G01R 29/00 G01R 29/08 H04B 17/00

Claims (1)

(57) [Claims] 1. An adjacent channel leakage power measuring method for measuring adjacent channel leakage power of a signal transmitted through a filter, the method comprising calculating a frequency width, a channel interval from a carrier wave to upper and lower adjacent channels, and a shape of the filter. Setting the constant of the filter, obtaining the height of the filter as correction data for each frequency point within the bandwidth defined by the frequency width and the channel interval, and obtaining the total power sum from display waveform data. Weighting and correcting the display waveform data of the lower adjacent channel with the correction data, and integrating the results to obtain the power sum of the lower adjacent channel; and correcting the display waveform data of the upper adjacent channel with the correction data. And summing the results to obtain the power sum of the upper adjacent channel. Calculating the lower adjacent channel leakage power and the upper adjacent channel leakage power by dividing the power sum of the lower adjacent channel and the power sum of the upper adjacent channel by the total power; and Displaying the upper adjacent channel leakage power.