JP2003234663A - Reception level measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To recognize the levels of signals from respective satellites and the difference of these levels at a glance on a display screen when an antenna direction is adjusted in a device for measuring and displaying the signal level of reception signals from a reception antenna capable of receiving radio waves from two earth satellites. <P>SOLUTION: The reception signals from the two satellites A and B are alternately outputted from the reception antenna, the signal of a prescribed channel is tuned for the respective signals, the signal levels are measured and the measured results are parallelly displayed by bars on the display screen. In the bar display, for the satellite A of a higher signal level, the number Na of lighting pixels is calculated so as to display the level by the unit of 2 dB per pixel with the bar display part 17a of the satellite A. For the satellite B of a lower signal level, the number of the pixels corresponding to the level difference ΔL from the satellite A is calculated by the unit of 0.2 dB per pixel and the calculated number of the pixels is subtracted from the number Na of the lighting pixel of the other satellite so as to calculate the number Nb of the lighting pixels on the bar display part 17b of the satellite B. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention measures the signal level of a reception signal from a reception antenna which receives radio waves from two artificial satellites at the same time and selectively outputs a reception signal from any one of the artificial satellites. The present invention relates to a signal level measuring device.

[0002]

2. Description of the Related Art Conventionally, as a receiving antenna for receiving radio waves transmitted from an artificial satellite, for example, a receiving antenna used to enjoy a CS broadcasting service (Sky Perfect TV) provided by Sky Perfect Communications Co., Ltd. As described above, a receiving antenna configured to simultaneously receive radio waves from two satellites with one receiving antenna and selectively output one of the received signals obtained from each satellite according to a command from the outside. Are known.

Further, in the CS broadcasting service (sky perfect TV), two orthogonal polarizations are used for broadcasting radio waves in order to effectively use the electric waves, and the radio waves of such two orthogonal polarizations are received. In the receiving antenna, the polarization of the received radio wave can be designated from the outside for each receivable artificial satellite.

By the way, when installing this kind of receiving antenna, it is necessary to adjust the direction (azimuth angle, elevation angle) of the receiving antenna so that the radio waves from two artificial satellites can be received at the same time. Radio waves transmitted from satellites are orthogonal 2
When it is a polarized wave, the polarized wave of the radio wave from the artificial satellite is inclined depending on the receiving area, so it must be adjusted.

Therefore, conventionally, as a receiving level measuring device for easily adjusting such a receiving antenna,
From the receiving antenna, the received signals from the two artificial satellites are alternately output, the signal levels of the output received signals from the respective artificial satellites are sequentially measured, and the measured signal level of each artificial satellite is There has been proposed a bar graph-like display mode configured to display on one display device at the same time (see Japanese Patent Laid-Open No. 11-308182).

That is, in order to install the above-mentioned receiving antenna so that the radio waves from two artificial satellites can be simultaneously received,
Since the signal level of the received signal for each artificial satellite output from the receiving antenna may be set to be approximately the same level, in the above receiving level measuring device, the reception for each artificial satellite received by the receiving antenna is performed. The signal level of the signal is simultaneously displayed on the display device, and the user can easily adjust the receiving antenna direction by adjusting the receiving antenna direction so that the difference between the displayed signal levels becomes small. Of.

[0007]

However, in the reception level measuring apparatus proposed above, since the signal levels of the respective artificial satellites are displayed in the form of bar graphs with the same resolution, the difference between the signal levels of the respective artificial satellites is reduced. When it is small, there is a problem that the level difference cannot be identified on the display screen, and it is difficult to adjust the antenna direction so that the level difference disappears.

That is, when the direction of the receiving antenna is adjusted, it is necessary not only to reduce the level difference between the received signals of the respective artificial satellites but also to maximize the absolute level of the received signals. In the above proposed reception level measuring device, the level display range (dynamic range) of the signal level display area is enlarged so that the user can grasp the signal level at a glance. When the level change width per pixel becomes large (in other words, the resolution becomes low) and the level difference between the received signals of each artificial satellite is small, the level difference cannot be grasped from the display screen, and the antenna direction is changed. It cannot be adjusted with high precision.

In order to prevent such a problem, the level change width per pixel in the display area should be made small.
Although it is sufficient to increase the display area, such a measure causes a problem that the reception level measuring device is increased in size and cost. It is also conceivable to reduce the level display range (dynamic range) of the display area and switch the level display range of the display area according to the signal level of the received signal, so-called range switching.
When such range switching is performed, the user needs to confirm the display range in the display area and read the signal level. Moreover, when the difference in signal level between the artificial satellites is large, Since the display areas are set to different display ranges, there is a problem that it is not possible to grasp the level difference between the received signals of the artificial satellites on the display screen.

The present invention has been made in view of these problems, and in a reception level measuring device for measuring the signal level of a reception signal output from a reception antenna capable of simultaneously receiving radio waves from two artificial satellites, An object of the present invention is to make it possible to grasp at a glance the signal level and the level difference of the received signal from each artificial satellite without increasing the level display area.

[0011]

According to another aspect of the present invention, there is provided a receiving level measuring device in which the artificial satellite designating means is a receiving antenna capable of receiving radio waves from two artificial satellites. On the other hand, by alternately switching and specifying the artificial satellites to be received, the receiving signals from the two artificial satellites are alternately output from the receiving antenna,
The channel selection means sequentially takes in the reception signals from the respective artificial satellites alternately output from the reception antenna, selects the signal of the specific channel included in the reception signal, and the level detection means selects the channel. The signal level of the reception signal of the specific channel of each artificial satellite is detected.

Further, in the receiving level measuring apparatus according to the first aspect, two long display areas are set so that the signal level detected by the level detecting means can be displayed in parallel for each artificial satellite. Is provided with a display means,
The display control means illuminates the level display pixels from one end side to the other end side in each display area of the display means, whereby the signal of the received signal from each artificial satellite detected by the level detection means. Display levels in parallel.

Further, when the display control means displays the signal level of the received signal from each artificial satellite in each display area of the display means, among the signal levels of each artificial satellite detected by the level detection means, For the first artificial satellite having a high level, the display area from the signal level detected by the level detecting means is displayed so that the signal level of the received signal is displayed in units of the first level per pixel in the display area of the display means. In the second artificial satellite whose signal level of the received signal is lower than that of the first artificial satellite, the number of lit pixels in is calculated so that the level difference from the first artificial satellite becomes clear on the display screen of the display means. The number of pixels corresponding to the level difference between the signal levels of the respective artificial satellites detected by the level detecting means is set to the second level in which the signal level per pixel in the display area is smaller than the first level unit. Calculated in place, by subtracting the number of pixels that calculated from the number of lit pixels for the first satellite, and calculates the number of lighting pixels in the display area.

As a result, in the display means, the signal level of the received signal is displayed in the first level unit in the display area of the first artificial satellite in which the signal level of the received signal from the receiving antenna is high, and the signal is received by the receiving antenna. In the display area of the second artificial satellite in which the signal level of the signal becomes low, the signal level of the received signal has a larger level difference with respect to the first artificial satellite than when the signal level is displayed in the first level unit. Will be displayed.

Therefore, the first signal having a high signal level is received.
In the display area of the artificial satellite, the signal level can be displayed in a large dynamic range without switching the display range, and the user can easily see the signal level of the received signal by seeing the level display in the display area. I can figure it out.

Further, in the display area of the second artificial satellite in which the signal level of the received signal is low, the signal level is displayed so that the level difference of the received signal with respect to the first artificial satellite becomes large. From the difference in the level display in the display area, the level difference in the received signal from each artificial satellite can be easily grasped.

Therefore, by using the receiving level measuring device according to the first aspect, the direction of the receiving antenna can be adjusted easily and highly accurately by adjusting the direction of the receiving antenna while confirming the display state of the display means. . Here, the tuning unit selects a signal of a specific channel whose signal level is to be measured from the reception signals from the artificial satellites alternately output from the receiving antenna. The specific channel to be used may be preset for signal level measurement, or may be externally designated by the user.

Further, when the receiving antenna receives the radio waves of orthogonal two polarizations transmitted from the two artificial satellites and outputs the received signal from the designated artificial satellite, the polarized wave designated from the outside is used. When the reception signal of the wave is configured to be selectively output, the artificial satellite designating means may be added to the satellite selection signal for designating the artificial satellite with respect to the receiving antenna as described in claim 2. The polarization designation signal for designating the polarization of the reception signal output by the reception antenna may be output.

In this case, it is desirable that the polarized wave designated by the artificial satellite designation means can be designated by the user from the outside. That is, with the channel selected by the channel selection means fixed, the polarization of the received signal output by the receiving antenna is switched, and when the signal level after switching is relatively high, the receiving antenna can favor two orthogonal polarized waves. Since it can be determined that it is not separated into two parts, if the user can specify the polarization of the reception signal output by the reception antenna, for example, the reception signal of the specific polarization is output from the reception antenna and the antenna direction is adjusted. After that, the user can easily confirm the degree of separation of the two orthogonal polarizations by the reception antenna by switching the polarization of the reception signal output by the reception antenna.

When the signal level after switching the polarization is relatively high, the polarizations of the receiving antennas are switched alternately to check the signal level difference, and the difference should be large.
By adjusting the mounting angle of the reflector of the receiving antenna or the converter, the polarization plane of the receiving antenna can be easily adjusted.

On the other hand, the display means may be provided with only the two long display areas for signal level display described above. For example, as described in claim 3, these display areas are Separately, a numerical value display unit for numerically displaying the signal level may be provided for each artificial satellite.

In this case, the display control means displays the signal levels of the respective artificial satellites on the numerical display section separately from the parallel display of the signal levels on the two long display areas. By doing so, the user can confirm the signal level (absolute level) of each artificial satellite by reading the value displayed on the numerical display, and the direction of the receiving antenna can be adjusted with higher accuracy. You can

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 receives a reception signal from a reception antenna 2 which receives radio waves of two orthogonal polarizations transmitted from two artificial satellites (hereinafter referred to as satellite A and satellite B), and displays the signal level thereof. It is a block diagram showing the whole structure of the reception level measuring apparatus 10 of a present Example.

As shown in FIG. 1, in this embodiment, an offset type parabolic antenna is used as the receiving antenna 2, and the reflecting mirror 4 of the receiving antenna 2 places the receiving antenna 2 on the roof or the ground. It is attached to a column 6 which is erected on a fixed base 7 for fixing, via a support tool (not shown) capable of adjusting the elevation angle and azimuth angle of the reflecting mirror 4, and in some cases the rotation angle. Further, the support receives the vertically and horizontally polarized radio waves from the respective satellites A and B collected by the reflecting mirror 4, and outputs either polarization signal in a predetermined frequency band (950 to 1880 MHz). A converter 30 for converting into one intermediate frequency signal (RF signal) and outputting this as a reception signal is attached via the support arm 8.

Then, as shown in FIG. 2, the converter 30 receives vertically and horizontally polarized waves from the satellite A collected by the reflecting mirror 4 and guided by the circular waveguide 32 through the probes P1 and P2. And a first wave receiving portion 34 for receiving the vertical and horizontal polarized waves from the satellite B collected by the reflecting mirror 4 and guided to the circular waveguide 33 via the probes P3 and P4. Two wave receiving portions 35 are provided.

Of these, the first wave receiver 34 is connected to the probe P.
1, a vertical polarization signal amplification circuit 34a for amplifying the output signals from P2, that is, a vertical polarization signal and a horizontal polarization signal, and a horizontal polarization signal amplification circuit 34b, and each polarization signal amplification circuit 34.
and a mixing circuit 34c for mixing the output signals from a and 34b. On the other hand, the second wave receiving unit 35 includes the first wave receiving unit 3
4 has the same configuration as that of FIG. 4, and has a vertical polarization signal amplification circuit 35a and a horizontal polarization signal amplification circuit 35b for amplifying the vertical and horizontal polarization signals from the probes P3 and P4, respectively.
And a mixing circuit 35c for mixing the output signals from the respective polarization signal amplification circuits 35a and 35b.

The polarization signal amplifier circuits 34a, 34b,
Reference numerals 35a and 35b are well-known low noise amplifying circuits mainly including a high electron mobility transistor (HEMT) that operates by receiving positive and negative power source voltages, and both receiving units 34 and 35 are provided.
Each of the vertical polarization signal amplification circuits 34a and 35a of
Vv, the positive power supply + Vh is applied to each of the horizontal polarization signal amplification circuits 34b and 35b, and the negative power supply -Va and the second reception wave are applied to both polarization signal amplification circuits 34a and 34b of the first wave receiving unit 34. A negative power supply -Vb is applied to both polarization signal amplification circuits 35a and 35b of the unit 35. Then, one of the positive power supplies + Vv and + Vh is supplied from the positive power supply circuit 45 described later, and one of the negative power supplies -Va and -Vb is supplied from the negative power supply circuit 46 described later, respectively. Depending on the combination of power supplies, any one of the polarization signal amplifier circuits 34a, 34b, 35a, 35b to which both positive and negative power supplies are applied is selectively driven.

Further, the converter 30 includes the wave receiving portions 34,
Mixing circuit 36 for mixing output signals from 35 and high-frequency amplifier circuit 37 for amplifying output signals from mixing circuit 36
And the output signal from the high-frequency amplifier circuit 37 is mixed with the output signal from the local oscillator circuit 38 to convert the frequency,
The mixer 39 for generating the F signal and the intermediate frequency amplifier circuit 40 for amplifying the RF signal generated by the mixer 39 are provided, and the amplified RF signal is used as the DC blocking capacitor 4
1, and is configured to be output to the transmission line 9 (see FIG. 1) via the input / output terminal 42.

Further, the converter 30 includes a capacitor C
1, C2 and a coil L, a low-pass filter 43 for extracting only a DC component from an input applied to the input / output terminal 42 via the transmission line 9, and each part of the converter 30 based on the output of the low-pass filter 43. A constant voltage circuit 44 for generating a positive power source + Vc and a negative power source −Vc for driving the power source, and a positive power source + V for the first and second wave receiving units 34 and 35.
Positive power supply circuit 45 for supplying either v or + Vh
And a negative power supply −Va, − to the first and second wave receiving portions 34 and 35.
An output voltage of the negative power supply circuit 46 that supplies any of Vb and the low-pass filter 43 (hereinafter, referred to as a power supply voltage)
Is compared with a preset comparison voltage (13 V in this embodiment), and the positive power supply circuit 45 is controlled so that the positive power supply + Vv is supplied when the voltage is lower than the comparison voltage and the positive power supply + Vh is supplied when the voltage is higher than the comparison voltage. Tone signals (32k to 5k) are input to the polarization switching control circuit 47 and the input applied to the input / output terminal 42.
3 kHz) is superposed, and if superposed, negative power supply −Va, if not superposed, negative power supply −
The satellite switching control circuit 48 controls the negative power supply circuit 46 so that Vb is supplied.

That is, in the converter 30, the input / output terminal 4
Specify either satellite A or B depending on whether the tone signal is superimposed on the input from 2 and specify either vertical or horizontal polarization depending on whether the power supply voltage is lower than the comparison voltage. Then, the designated polarized wave from the designated satellite is received and converted into an RF signal, which is output from the input / output terminal 42 as a received signal.

A positive power supply circuit 45, a negative power supply circuit 46, a polarization switching control circuit 47, and a satellite switching control circuit 48.
Are disclosed in, for example, Japanese Patent Laid-Open No. 4-135328 and Japanese Patent Laid-Open No.
Since this is a well-known one described in Japanese Patent Publication No. 171043, etc., a detailed description thereof will be omitted here.

Next, the reception level measuring apparatus 10 of this embodiment
As shown in FIG. 1, a DC component serving as a power source for the converter 30 is applied to the transmission line 9 via the input / output terminal 11, and a reception signal (RF) input from the converter 30 via the transmission line 9 is applied. R) in accordance with the power source separation filter 12 for separating the signal) from the DC component and the tuning signal Ss described later.
From a channel selection circuit 13 that converts a signal of a specific channel in the F signal into a second intermediate frequency signal (IF signal) in the 400 MHz band (center frequency 402.78 MHz; corresponding to the output frequency) and outputs the signal. Demodulation circuit 14 for demodulating the IF signal of A, and the A / D converter 1 for converting the voltage level of the demodulation signal generated by the demodulation circuit 14 (that is, the signal level of the channel selected by the channel selection circuit 13) into a digital value.
5 and.

Further, the reception level measuring device 10 includes an operation unit 16 for designating the polarization, channel, etc. of each satellite A, B whose reception level is to be measured, and a display device 17 including a liquid crystal display panel or the like. , A DC component to be supplied to the display control circuit 18 for driving the display device 17 and the converter 30, and the voltage (feed voltage) thereof is used as the polarization switching signal Sv.
Accordingly, the high voltage for specifying the horizontal polarization (15 in this embodiment)
V) or a low voltage for vertical polarization selection (11 in this embodiment).
V) which is set to any one of V), a tone signal generation circuit 20 which generates a tone signal in accordance with the satellite switching signal St, and a DC signal generated by the voltage generation circuit 19, which superimposes the tone signal on the power supply. It is composed of a signal superimposing circuit 21 supplied to the separation filter and a well-known microcomputer mainly composed of a CPU, a ROM and a RAM, and a tuning signal S for each satellite A and B according to the operation of the operation unit 16.
s, the polarization switching signal Sv, and the A / D converter 15
Each satellite A, B based on the voltage level read via
The reception level and the like of the display device 1 via the display control circuit 18.
7, and a control circuit 22 for executing display control to be displayed on the display device 7.

The signal superimposing circuit 21 includes a transistor T
A first switching circuit including R1, resistors R1 and R2, which connects and disconnects the power supply path from the voltage generation circuit 19 to the power supply separation filter 12, a diode D connected in parallel to the transistor TR1 with the power supply direction as the forward direction, and the transistor TR2. , Resistors R3, R4, and a second switching circuit that controls ON / OFF of the first switching circuit in accordance with the tone signal output from the tone signal generation circuit 20.

The output of the tone signal generating circuit 20 is
At the High level, both the first and second switching circuits (that is, the transistors TR1 and TR2) are turned on, so that the power supply voltage supplied to the power supply separation filter 12 is higher than the output voltage of the voltage generation circuit 19 by the transistor. T
A voltage drop (0.1%) at the collector-emitter voltage of R1.
.About.0.3 V). On the other hand, when the output of the tone signal generation circuit 20 is at the Low level, both the first and second switching circuits are in the OFF state, so the power supply voltage supplied to the power supply separation filter 12 is the output voltage of the voltage generation circuit 19. Therefore, the diode D becomes smaller by the forward voltage (0.7 to 0.9 V).

Therefore, when the tone signal is being output from the tone signal generating circuit 20, the tone signal having an amplitude of 0.6 ± 0.2 [V] is superimposed on the DC component output from the voltage generating circuit 19. This will be supplied to the power supply separation filter 12. Then, as described above, satellite A
To specify, the tone signal is superposed, when satellite B is specified, the tone signal is not superposed, and when horizontal polarization is specified, the power supply voltage is set to 15 V and vertical polarization is set. When specified, the power supply voltage is set to 11 V, so the output waveform of the signal superimposing circuit 21 in each case where these are combined, that is, the transmission line 9
The waveform of the component supplied to the converter 30 via the waveform is as shown in FIG.

Next, the control circuit 22 sets the channel selection signal Ss and the polarization switching signal Sv in accordance with the operation of the operation unit 16 as described above, and alternately switches the output of the satellite switching signal St, For each of the satellites A and B, the signals of the polarization and the channel designated by the user are selected by the tuning circuit 13 alternately, and the signal level (voltage level) is sequentially read from the A / D converter 15.

The control circuit 22 then reads the signal levels of the respective satellites A and B, the reception channels (CH) of the respective satellites A and B, the plane of polarization (horizontal polarization: H, or vertical polarization V). ) Or the like is generated on the display device 17 at the same time, and the generated display data is output to the display control circuit 18 to be displayed on the display device 17 at the same time.

FIG. 4 shows the measurement result of the reception level actually displayed on the display device 17 by the series of control processes of the control circuit 22. As shown in FIG. 4, the display screen of the display device 17 is set to be long in order to display the signal levels of the satellites A and B in parallel in an analog manner.
One display area (hereinafter referred to as bar display section) 17a, 1
7b and the signal level (reception level) of each satellite A, B is received CH (CH3 in the figure), plane of polarization (vertical polarization V in the figure)
Numerical display part 1 for displaying numerical values together with other received information of
7c.

Further, each bar display section 17a, 17b has a plurality of vertically long pixels set for level display at substantially equal intervals in the horizontal direction of the display screen in order to display the signal level in a bar (in this embodiment). (16 in this case) are arranged. Then, the control circuit 22 displays the signal level of the satellite having a high signal level (satellite A in the figure) of the two satellites A and B on the corresponding bar display section (17a in the figure). Is in the practical range of 60 dBμ to 90 dBμ
As the number of pixels required to display the signal level with a resolution of 2 dB per pixel (first level unit according to claim 1), the corresponding bar display unit (for the display control circuit 18) is calculated. In the figure, the signal level is displayed as a bar by turning on the pixels by the number of pixels calculated from the left end side in 17a).

Further, the control circuit 22 uses the two satellites A and B.
Among them, the signal level of the satellite with a low signal level (satellite B in the figure) corresponds to the level difference so that the level difference with the other satellite (satellite A in the figure) becomes clear on the display screen. The number of pixels is indicated by the corresponding bar display (17 in the figure).
The signal level per pixel in b) is 0.2 dB, which is 1/10 of 2 dB when the level of the other satellite is displayed.
The number of pixels for level display is calculated by subtracting the calculated number of pixels from the number of pixels for level display on the bar display section of the other satellite (second level unit according to claim 1). Then, the signal level is bar-displayed on the display control circuit 18 by turning on the pixels by the number of pixels calculated from the left end side in the corresponding bar display unit (17a in the figure).

The reception level measuring process executed by the control circuit 22 in this manner will be described below with reference to the flowchart shown in FIG. Before starting this process, the type of polarization for which the reception level should be measured via the operation unit 16,
It is assumed that the channel is set and the setting contents are stored in a predetermined area of the RAM. Further, once this process is started, it is repeatedly executed thereafter. However, if the above setting is changed via the operation unit 16 during execution, the value stored in the RAM is changed according to the change. It shall be updated.

As shown in FIG. 5, when this processing is started, first, in S100 (S represents a step), R
The setting content stored in the AM is read, and in the subsequent S110, it is determined whether horizontal polarization is designated as the type of polarization based on the read setting content.

If horizontal polarization is designated as the type of polarization, the voltage generation circuit 19 is selected in S120.
After the polarization switching signal Sv is set so that the power supply voltage from is a high voltage (15V), the process proceeds to S140, and if vertical polarization is specified as the type of polarization, the voltage is generated in S130. The power supply voltage from the circuit 19 is low (11
V), the polarization switching signal Sv is set, and then S14
Go to 0.

Next, in S140, in order to measure the signal level of the received signal (RF signal) from the satellite A, the satellite switching signal St is set so that the tone signal is output from the tone signal generation circuit 20, and the subsequent operation is continued. In S150, the signal of the channel designated for the satellite A is selected from the RF signals based on the setting contents read in S110.
Channel selection signal Ss so that it is selected in 3 and converted to an IF signal
Is set, and at S160, the IF from the tuning circuit 13 is set.
The voltage level of the demodulated signal obtained by demodulating the signal in the demodulation circuit 14 is read from the A / D converter 15 as the signal level La of the received signal from the satellite A and stored in a predetermined area of the RAM.

Next, at S170, in order to measure the signal level of the reception signal (RF signal) from the satellite B, the satellite switching signal St is set so that the tone signal is not output from the tone signal generating circuit 20. Then, in S180, based on the setting contents read in S110, a signal of a channel designated for the satellite B is selected by the tuning circuit 13 and converted into an IF signal from the RF signals. The station signal Ss is set, and in the subsequent S190, the voltage level of the demodulation signal obtained by demodulating the IF signal from the channel selection circuit 13 in the demodulation circuit 14 is set as A / A as the signal level Lb of the reception signal from the satellite B. Read from D converter 15,
Store in a predetermined area of RAM.

Then, in the subsequent S200, the signal level L of the received signals from the respective satellites A and B measured as described above.
The reception level display processing for displaying a and Lb on the display device 17 via the display control circuit 18 is executed, and the processing is ended once. Next, FIG. 6 is a flowchart showing details of the reception level display processing executed in S200.

As shown in FIG. 6, in the reception level display processing, first in S210, the signal levels La and Lb of the satellites A and B measured as described above are read out from the RAM,
The level difference ΔL (absolute value) of each signal is calculated. And
In the subsequent S220, the signal levels La and Lb of the satellites A and B are determined by judging whether the signal level La is equal to or higher than the signal level Lb. If the signal level La is equal to or higher than the signal level Lb, At S230 and S240, the signal levels La and L are displayed on the bar display portions 17a and 17b.
The numbers of lit pixels Na and Nb for displaying b are sequentially calculated.

That is, in S230, the number Na of lit pixels for displaying the signal level of the satellite A having a higher signal level on the bar display unit 17a in a bar is calculated by the following equation (1) Na = (La-60) / 2 + 1. ... is calculated using (1), and in S240, the number of lit pixels Nb for displaying the signal level of the satellite B having a lower signal level on the bar display unit 17b in the form of the following expression (2) Nb = Na- (ΔL / 0.2) ... Calculated using (2).

In the above equations (1) and (2), the value "60" represents the minimum display level of 60 dBμ in the level display section (17a in this case) on the high signal level side. “2” represents 2 dB, which is the signal level per pixel in the level display unit on the side where the signal level is also high, and the value “0.2” is the level display unit on the side where the signal level is low (here, 17b). Represents a signal level per pixel of 0.2 dB.

Therefore, as shown in FIG. 4, the signal level of satellite A is 84.4 dBμ and the signal level of satellite B is 83.
In the case of 6 dBμ, the number of lit pixels Na in the bar display portion 17a is 13 from the following expression Na = (84.4-60) /2+1=13.2, and the number of lit pixels Nb in the bar display portion 17b is Nb. Is 9 from the following expression Nb = 13− (84.4-83.6) /0.2=9.

On the other hand, when it is determined in S220 that the signal level La is lower than the signal level Lb, S2
50 and S260, the number N of lit pixels for displaying the respective signal levels Lb, La on the bar display portions 17b, 17a.
b and Na are calculated in order. That is, in S250, the signal level of the satellite B having the higher signal level is displayed by the bar display unit 17b.
The number Nb of lit pixels for displaying a bar on the display is calculated using the following equation (3) Nb = (La-60) / 2 + 1 (3), and in S260, the signal level of the satellite A with the lower signal level is calculated. The number Na of lit pixels for bar display on the bar display unit 17a is calculated using the following equation (4) Na = Nb− (ΔL / 0.2) (4).

The value "6" in the above equations (3) and (4)
“0”, “2”, and “0.2” have the same values as those in the respective arithmetic expressions (1) and (2). In this way, S230, S240 or S25
0, when the lighting pixel numbers Na and Nb in the bar display portions 17a and 17b are calculated in S260, the calculated lighting pixel numbers Na and Nb are output to the display control circuit 18 in S270. Each bar display unit 17 of the display device 17
At a and 17b, the pixels are lit from the left end side by the number of lit pixels Na and Nb. As a result, on the display screen of the display device 17, as illustrated in FIG. 4, the signal levels of the satellites A and B are displayed in parallel in bars.

Then, in the following S280, each satellite A, B
By outputting the data representing the reception CH, the polarization plane, and the signal levels La and Lb to the display control circuit 18, the numerical display unit 17c of the display device 17 numerically displays each of these data, and the reception level display processing is ended. To do.

As described above, in the reception level measuring apparatus 10 of this embodiment, the signal levels La, of the reception signals from the two satellites A and B that can be received by the reception antenna 2 are obtained.
When Lb is displayed in parallel on the display screen of the display device 17 by a bar, for the satellite A (or B) having a high signal level, the bar display portion 17a (or 17b) of the satellite A (or B) is displayed.
In order to display the signal level La (or Lb) in units of 2 dB per pixel, the bar display section 17a (or 1
7b) the number of illuminated pixels Na (or Nb) is calculated, and for satellite B (or A) with a low signal level, another satellite A
Calculate the number of pixels corresponding to the level difference ΔL between the signal levels La and Lb of the two satellites A and B in 0.2 dB units per pixel so that the level difference ΔL from (or B) becomes clear. Then, the calculated number of pixels (= ΔL / 0.2) is subtracted from the number of lit pixels Na (or Nb) for other satellites to obtain the number of lit pixels Nb (or Na) in the bar display unit 17b.
Is calculated, and each bar display unit 1 is calculated based on these calculation results.
The pixels 7a and 17a are lit up from the left end.

As a result, in the display device 17, the bar display portion 17a (or 17b) of the satellite A (or B) of the two satellites A and B, which has a higher signal level, displays the received signal level La ( Or Lb) is displayed in 2 dB units as a bar, and the signal level Lb (or La) of the received signal is displayed in 2 dB units on the bar display portion 17b (or 17a) of the satellite B (or A) where the signal level becomes low. The bar is displayed so that the level difference with respect to the satellite A (or B) is larger (10 times in the present embodiment) than when displayed in.

Therefore, the reception level measuring apparatus 1 of this embodiment
If 0 is used, the bar display unit 17a (or 17b) of the satellite A (or B) having a high signal level can display the signal level La (or Lb) in a bar with a large dynamic range without switching the display range. The user can easily grasp the signal level by looking at the level display on the bar display portion 17a (or 17b).

Further, satellite B (or A) having a low signal level
In the bar display portion 17b (or 17a) of, the signal level L is set so that the level difference ΔL with the satellite A (or B) becomes large.
Since b (or La) is displayed, the user can determine the difference between the level displays on the two bar display units 17a and 17b.
The level difference ΔL between the received signals from the satellites A and B can be easily grasped.

Therefore, the reception level measuring apparatus 1 of this embodiment
If 0 is used, the bar display unit 17 in the display device 17
By adjusting the direction of the receiving antenna 2 while confirming the display states of a and 17b, the direction of the receiving antenna 2 can be easily adjusted to the optimum direction for receiving the transmission radio waves from the two satellites A and B. It becomes possible to adjust with high precision.

Further, the reception level measuring apparatus 10 of this embodiment
Then, in addition to displaying the signal levels of the satellites A and B on the bar display units 17a and 17b of the display device 17 as a bar, a numerical value display unit set at a position different from the bar display units 17a and 17b of the display device 17 is provided. Since it is displayed numerically on 17c,
The user can also confirm the signal level (absolute level) of the received signals from the satellites A and B by reading the numerical value displayed on the numerical value display unit 17c.

Therefore, the user can select the bar display portions 17a, 1
Whether or not the orientation of the receiving antenna 2 is proper is confirmed by checking the signal level (absolute level) of the receiving signals from the satellites A and B after adjusting the orientation of the receiving antenna 2 while watching the display state on 7b. Therefore, the direction of the receiving antenna 2 can be adjusted more reliably.

In this embodiment, the display device 17 and the display control circuit 18 correspond to the display means of the present invention, and the channel selection circuit 13 and the control circuit 22 for selecting the signal of the designated channel. The processing of S150 and S180 executed corresponds to the channel selection means of the present invention, and the processing of 160 and S190 of reading the signal level from the demodulation circuit 14, the A / D converter 15, and the A / D converter 15 of the present invention. It corresponds to a level detecting means. Further, among the processes executed by the control circuit 22, the polarization switching signal Sv and the satellite switching signal St are set so that the reception signals (RF signals) of the respective satellites A and B are alternately output from the reception antenna 2. S120 ~ S
The processing of 140 and S170 corresponds to the artificial satellite designation means of the present invention, and the reception level display processing (FIG. 6) executed at S200 corresponds to the display control means of the present invention.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various modes can be adopted. For example, in the above embodiment, the display device 17 has been described as performing not only the bar display of the signal levels of the satellites A and B but also the numerical display at the same time. The bar display of the level may be performed, and the display form on the display device 17 may be switched to the numerical display only when specified by the user.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of a reception level measuring apparatus according to an embodiment.

FIG. 2 is a block diagram showing a schematic configuration of a converter of a receiving antenna.

FIG. 3 is a graph showing an output waveform of a signal superimposing circuit of the reception level measuring device.

FIG. 4 is an explanatory diagram showing a display state of a signal level on a display device.

FIG. 5 is a flowchart showing a reception level measurement process.

FIG. 6 is a flowchart showing a reception level display process.

[Explanation of symbols]

2 ... Receiving antenna, 9 ... Transmission line, 10 ... Receiving level measuring device, 12 ... Power separation filter, 13 ... Channel selection circuit, 14
... Demodulation circuit, 15 ... A / D converter, 16 ... Operation unit,
17 ... Display device, 18 ... Display control circuit, 19 ... Voltage generation circuit, 20 ... Tone signal generation circuit, 21 ... Signal superposition circuit, 22 ... Control circuit, 30 ... Converter.

Claims (3)

[Claims] 1. A receiving antenna configured to receive radio waves from two artificial satellites and selectively output a received signal from one artificial satellite designated from the outside, with respect to the two artificial satellites. So as to alternately output the received signals from the receiving antennas, the artificial satellites are alternately output from the receiving antenna according to the artificial satellites designated by the artificial satellites designated by the artificial satellites. Receiving signals from each artificial satellite are sequentially taken in, and a tuning means for tuning a signal of a specific channel included in the receiving signal, and a receiving signal of a specific channel of each artificial satellite selected by the tuning means Level detecting means for detecting the signal level of each of the artificial satellites, and two long-length-shaped signals set so that the signal levels detected by the level detecting means can be displayed in parallel for each of the artificial satellites. Display means having a display area, and by turning on a pixel for level display from one end side to the other end side in each display area of the display means, from each of the artificial satellites detected by the level detection means And a display level control unit for displaying the signal level of the received signal in parallel, and the display control unit is one of the signal levels of the respective artificial satellites detected by the level detection unit. As for the first artificial satellite having a high level, the signal level of the received signal is displayed from the signal level detected by the level detection unit so that the signal level of the received signal is displayed in units of the first level per pixel in the display area of the display unit. The number of lit pixels in the display area is calculated, and for the second artificial satellite whose received signal level is lower than that of the first artificial satellite, the first artificial satellite is displayed on the display screen of the display means. In order to clarify the level difference with the engineering satellite, the number of pixels corresponding to the level difference of the signal level of each artificial satellite detected by the level detecting means is calculated as the signal level per pixel in the display area. The number of lit pixels in the display area is calculated by calculating in a second level unit smaller than the first level unit and subtracting the calculated number of pixels from the number of lit pixels for the first artificial satellite. Receiving level measuring device. 2. The receiving antenna receives radio waves of two orthogonal polarizations transmitted from each of the two artificial satellites, and outputs a received signal from an artificial satellite designated from the outside from the outside. It is configured to selectively output a reception signal of a designated polarization, the artificial satellite designating means, with respect to the receiving antenna,
The polarization designation signal for designating the polarization of the reception signal output by the reception antenna is output in addition to the satellite selection signal for alternately switching and designating the artificial satellites to be received. Level measuring device. 3. The display means includes, in addition to two elongated display areas for displaying the signal levels detected by the level detection means in parallel for each artificial satellite, for each artificial satellite. A numerical value display unit for numerically displaying the signal level is provided, and the display control means separately from the parallel display of the signal level in the two long display areas, displays the artificial satellites of the respective satellites in the numerical value display unit. The reception level measuring device according to claim 1 or 2, wherein the signal level is displayed numerically.