JPH07209353A - Spectrum analyzer - Google Patents

Abstract

PURPOSE:To provide a spectrum analyzer for measuring the signal levels of amplitude modulated image signal and frequency modulated sound signal for television, for example, on one measuring screen. CONSTITUTION:An incoming signal is A/D-converted, processed and then the waveform thereof is displayed on a display section in a conventional spectrum analyzer. In this inventive spectrum analyzer, an operating/controlling means, a memory section 26 and a screen division setting section 27 are provided in place of the operating section. A maximum value, a minimum value, an average value and a measured value are stored for every measurement. By the command from the screen division setting section 27, the screen is partitioned and a maximum value data or an average value data, for example, are displayed in dot on each partitioned screen thus displaying a required signal waveform on one screen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectrum analyzer for analyzing and displaying a foreign signal.

[0002]

2. Description of the Related Art FIG. 4 shows a block diagram of a conventional spectrum analyzer. External signal f71 is input terminal 1
0 and is mixed with the signal f73 from the sweep oscillator 18 in the first mixer 11. Then, the difference signal between the external signal f71 and the signal f73 from the sweep oscillator 18 is taken out as the first intermediate frequency f72. This first intermediate frequency f7
2 is mixed with the signal from the fixed oscillator 19 in the second mixer 12, and the difference signal is extracted as the second intermediate frequency f74.

Next, the second intermediate frequency 74 is passed through a BPF (band pass filter) 13 to generate an external signal f.
71 is extracted. Then, the detection / A / D unit 14 detects and A / D-converts the data, and the calculation unit 15 performs necessary calculations and displays the result on the display unit 17. Lamp voltage generator 20
Generates a lamp voltage and supplies the lamp voltage to the sweep oscillator 18 and the display unit 17.

The spectrum analyzer configured as described above displays a spectrum of an external signal and measures the signal level, occupied bandwidth, spurious and the like. By the way, in the conventional spectrum analyzer, whether the signal waveform is the measured value (REAL) or the maximum value (MAX) at that time,
Only one of the average value (AVE) and the minimum value (MIN) could be measured and displayed.

By the way, there are cases where signals having different modulation systems, such as a television modulation signal, in which a video signal is AM modulation and an audio signal is FM modulation, are simultaneously measured. At this time, it is necessary to measure the maximum value of the signal level for the video signal and the average value of the audio signal. In such a case, conventionally, only one of them can be measured. Therefore, first measure the maximum value and measure the video signal.
At the fourth time, the average value was measured and the voice signal was measured.

As described above, in order to measure / analyze one signal, it is necessary to change the measurement specifications and perform the measurement twice, which is twice as long as the one measurement, which is inconvenient and may be wrong. There was also.

[0007]

SUMMARY OF THE INVENTION The present invention is a spectrum analyzer capable of measuring the maximum value, the average value, and the minimum value of a signal level with one measurement, and also displaying them in one screen. The purpose is to provide.

[0008]

In order to achieve the above object, the present invention replaces the conventional arithmetic unit with a μCPU (micro computer) having an arithmetic / control function, and additionally, a memory unit and a screen. A new division setting unit will be provided. The calculation / control means (hereinafter referred to as “μCPU”), the memory unit, and the screen division setting unit will be described below.

The μCPU has two functions. One is a function of performing arithmetic processing on measurement data, and the other is a function of splitting the screen display of the display unit. The arithmetic processing function is to compare the measured digital data with past data and process them. Then, the maximum value of the signal level is selected and stored in the waveform measured a certain number of times, the minimum value is selected and stored, or the average value is calculated and stored. In addition, as the calculation, the signal level of the Y axis is set in various units,
For example, 10 dB / DIV, 2 dB / DIV or LINEA
The calculation for converting to R or the like, the calculation for converting the frequency unit of the X axis into the linear unit or the logarithmic unit, and other necessary calculation are also performed.

Regarding the divided display, while maintaining continuity of the frequency display on the X axis, the screen display is divided on the display unit to display MAX (maximum value) in the first half and AVE in the second half.
(Average value) Controls to display. This division can be divided into a plurality of three or more screens.
Then, the condition is displayed below or above the screen. Further, in the same way, the amplitude level of the Y-axis can be divided, and the level unit can be made finer in the vicinity of the upper peak value and made coarser in the lower part.

The memory section stores the maximum value memory that stores only the maximum value of measured digital data, the minimum value memory that stores only the minimum value, the average value memory, and the specifications that store specifications input from an external setting device. There is memory etc. The memory section exchanges data with the μCPU, updates the data, and always stores new data.

In the screen division setting section, the measurer sets specifications of the screen division display condition, transmits the data to the μCPU, and specifies the work of the μCPU. The specifications may be set from the board, the numeric keypad, or the push button group. However, it is desirable to have a terminal with no operational mistakes.

【Example】

FIG. 1 shows an embodiment of the present invention. Portions corresponding to those in FIG. 4 are designated by the same reference numerals. 2 shows an example of the contents of the memory unit 26, and FIG. 3 shows an example of the screen display of the display unit 17.

An embodiment of FIG. 1 will be described. Foreign signal f7
Similarly to the conventional example, 1 is input from the input terminal 10 and converted into the first intermediate frequency signal f72 by the first mixer 11. Next, the second mixer 12 converts the second intermediate frequency signal f74 into a second intermediate frequency signal f74, and the BPF 13 extracts the external signal f71.
The D section 14 detects and performs A / D conversion. Generally, the display unit 1
Since the X-axis of the display screen of 7 is displayed with data of about 700 points, the detection / A / D unit 14 makes about 70 in one sweep.
A / D conversion is performed 0 times.

The A / D converted digital data is first stored in the memory section 26 through the μCPU 25 having an arithmetic / control function. The μCPU 25 exchanges data with the memory unit 26 and performs arithmetic processing using this measured value data. For example, if it is larger than the previously measured data, it is stored in the maximum value memory, and if it is larger than the maximum value data in the next measurement data, the maximum value memory is updated and stored. In this way, the data is constantly compared and the maximum value and the minimum value of the measurement are stored in the maximum value memory and the minimum value memory. Then, the measured values are averaged every fixed number of times, for example, 20 times, and the average value is stored in the average value memory. .

FIG. 2 shows an example of the memory contents of the memory unit 26. While exchanging data with the μCPU 25 as described above, the memory unit 26 stores at least the maximum value, the minimum value, the average value, the measured value, and externally set specifications in the respective memory units. In addition to that, it has sufficient spare memory.

The screen division setting section 27 is displayed on the display section 1 by the measurer.
7 is a setting unit for specifying the split screen display of 7. For example, the X axis of the display screen has a frequency of 10 MHz to 20 MHz
In the case of the display of, the maximum value display is 1 at 15MHz or less.
When the average value is required to be displayed at 5 MHz or more, the designation may be made.

FIG. 3 shows an example of the display screen of the display unit 17. FIG. 3A is an example in which the maximum value is displayed at frequencies lower than the center of the screen and the average value is displayed at frequencies higher than the center of the screen, as in the previous example. Then, a vertical line is entered in the center to display the division. There may or may not be a vertical line, as long as it indicates some division. In addition, the conditions are displayed here as MAX (maximum value) and AVE (average value). FIG. 3B is an example in which the screen display is divided into three conditions. The three categories are displayed from the low frequency under the conditions of MAX (maximum value), MIN (minimum value) and AVE (average value). In addition, although not shown or described, characters and symbols for level display and frequency display are displayed as in the past.

Here, a method of displaying by dividing will be described. As described above, the X-axis of the display unit 17 is divided into about 700 points, and the screen is displayed at the points based on the signal level data at each position. Therefore, FIG.
In the case of (A), for example, data from 0 to 350 points is read from the maximum value memory and displayed in dots on the screen, and MAX characters are inserted below or above. Three
It is advisable to read the data from 51 to 700 points from the average value memory and display them as dots, draw a line at 351 points as the A line for division, and put the letters AVE below or above.

In the case of FIG. 3B, for example, 0 to 233.
It is advisable to read the data from the maximum value memory up to the point, the minimum value memory from 234 to 466 points, and the average value memory from 467 to 700 points, display the dots, draw a dividing line, and put a character in each.

[0021]

As described above, according to the present invention, when measuring an external signal such as a television radio wave with a spectrum analyzer, measurement under different conditions such as maximum value signal measurement and average value signal measurement is performed once. It can be displayed on one screen. Although not described here, when the measurement is performed using the conventional automatic display of the level and frequency of the marker point, the measurement can be performed accurately and at high speed, and the technical and economic effects thereof are great.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of the inside of the memory unit of the present invention.

FIG. 3 is an explanatory diagram of screen display on the display unit of the present invention.

FIG. 4 is a configuration diagram of a conventional example.

[Explanation of symbols]

 10 Input Terminal 11 First Mixer 12 Second Mixer 13 BPF (Band Pass Filter) 14 Detection / A / D Converter 15 Calculation Unit 17 Display 18 Sweep Oscillator 19 Oscillator 20 Lamp Voltage Generator 21 BPF Setting Register 22 Center Frequency Setting register 23 Span setting register 25 Arithmetic / control means (μCPU) 26 Memory section 27 Screen division setting section

Claims (1)

[Claims] 1. A spectrum analyzer for inputting an external signal, converting to a low frequency by the hetrodyne system, detecting / A / D converting, and displaying a spectrum on a display unit with digital data, in an A / D conversion (14). An arithmetic / control unit (25) for later arithmetically processing the digital signal and controlling division display of the display screen of the display unit (16), and a screen for dividing the screen and setting division conditions in the arithmetic / control unit (25). A spectrum analyzer comprising: a division setting section (27); and a memory section (26) for storing data necessary for the calculation processing and display of the calculation / control means (25).