JP2003069464A - Digital modulation wireless relaying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital modulation wireless relaying device that can grasp a accurate transmission state by a BL (Before Limiter) tone monitor function. SOLUTION: In the case that an output of a detector 6 controls an oscillated frequency of a VCO 9 to change a tone color of a monitor tone generated from a speaker 10 and to monitor a level of a received signal R, when a digital modulation system is changed, a reception signal level changeover circuit 70 placed between the detector 6 and the VCO 9 can change an input voltage to the VCO 9 accordingly so that no effect appears on a monitor of a transmission line margin due to the change of the digital modulation system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital modulation wireless relay device, and more particularly to a digital modulation wireless relay device that acoustically monitors a transmission status.

[0002]

2. Description of the Related Art In a radio relay device, a stable relay operation largely depends on the condition of a received signal. Therefore, for some reason, for example, when the received electric field strength falls below a predetermined level, the signal to be relayed is reduced. Quality assurance becomes difficult.

Therefore, conventionally, the received electric field strength and the like are constantly monitored, and when there is a possibility that a trouble occurs in the continuation of stable relay operation, necessary corrective measures can be taken. B in the prior art of the time monitoring method
There is a monitor system called an L (Before Limiter) tone, that is, a BL tone monitor system.

FIG. 2 shows an example of a BL tone monitor type wireless relay device according to the prior art. In the figure, reference numeral 1 denotes a high frequency reception section of the wireless relay device.
The reception signal R is supplied from an antenna (not shown).

The received signal R is first transmitted to the LNA.
(Low noise figure amplifier), amplified to a predetermined level, converted to an IF (intermediate frequency) signal by the frequency conversion circuit 3, and band-limited by the SAW (surface acoustic wave filter) 4 to the signal of the adjacent channel. Is removed, then IFAMP
After being amplified by the (intermediate frequency amplifier) 5, it is supplied to the subsequent stage of the repeater.

Then, at this time, the output of the SAW 4 is also input to the wave detector 6, and the wave is detected here, so that the SAW 4
A DC voltage signal corresponding to the level of the signal output from is obtained. Since the input-output characteristic of the detector 6 has the characteristic of a quadratic curve, normally, the output of the detector 6 is converted into a digital signal by the A / D converter 11 and taken into the CPU 12, and after being converted into a linear characteristic, D / It is converted into an analog signal by the A converter 13 and input to the DC amplifier 7.

This is amplified by a DC amplifier 7 and then input as a control voltage to a VCO (voltage controlled oscillator) 9 for oscillating an audio frequency signal, and the oscillation frequency of this VCO 9 is controlled over a predetermined audio frequency range.

Therefore, when the signal output from the VCO 9 is supplied to the speaker 10, a pure tone whose tone color changes according to the level (carrier level) of the received signal R is generated from the speaker 10. When a maintenance person or the like hears the sound, the reception signal level can be perceptually obtained from the timbre of the monitor sound, which is a so-called BL tone monitoring method.

The oscillation frequency of the VCO 9 at this time is set as follows, for example. That is, when the level of the signal R input to the reception high frequency unit 1 of this wireless relay device is at a value that guarantees the specification rating of this wireless relay device, it is said that people hear and feel around 400 hertz. It is set so that

By doing so, when the received signal R is in the normal level range, even if the monitor sound is continuous, it does not matter so much, and the abnormality due to the level decrease can be surely recognized only when the timbre changes. Therefore, the monitor function can always be maintained reliably.

Although not shown in the figure, the BL tone monitor system is provided with a switch for stopping the supply of signals to the speaker, for example. It is customary to be able to stop the occurrence.

[0012]

The above-mentioned prior art does not consider application of the digital modulation method to a wireless relay system, and in this case, there is a problem that a sufficient monitoring function cannot be obtained. there were.

First, in the case of a digital modulation radio relay apparatus, the modulation method is a PSK (phase shift modulation) method or an ASK (amplitude shift modulation) method according to the element to be modulated.
There are various modulation methods such as the FSK (frequency shift modulation) method and the FSK method. Here, some of these elements include, in addition to any one of the above-mentioned phase, amplitude, and frequency of the carrier wave, a combination of these, and a multilevel number.

Then, in the radio repeater based on the digital modulation method, any one of these elements is selected, and the selected element is changed according to the information "0" and "1" of the digital signal to be transmitted. Although data transmission is obtained, at this time, each of the above-mentioned modulation methods has its own characteristic of transmission characteristics, and in particular, the BER (error occurrence rate) relative to C / N (carrier to noise ratio) is considerably high. Have a difference

Therefore, in the digital modulation type wireless relay system, the operation by the plurality of modulation methods described above is usually possible, and the relay operation can be performed by switching to any one of the modulation methods as needed. I am trying.

Then, in this case, even if the received electric field strength of the wireless relay device does not change and the received signal level is the same, a difference appears in BER depending on the modulation method adopted at that time. Become.

In the prior art, however, only the received signal level can be monitored by changing the electric field strength. Therefore, when applied to a digital modulation type wireless relay device,
We couldn't cope with the change of the modulation system, and as a result, we couldn't grasp the margin until the reception became impossible due to the lowered BER.
Therefore, there arises a problem that a sufficient monitor function cannot be obtained.

It is an object of the present invention to provide a digital modulation radio relay apparatus which can always obtain an accurate transmission status by a BL tone monitor function.

[0019]

SUMMARY OF THE INVENTION The above object is to provide a digital modulation wireless system of a type which performs a relay operation by any digital modulation method arbitrarily selected from a plurality of digital modulation methods and recognizes the relay operation status by a monitor sound. In the relay device, there is provided means for switching the tone color of the monitor sound with respect to the received signal level according to the selection of the digital modulation method.

[0020] Similarly, the above object is to provide a digital modulation radio relay apparatus of a system which performs a relay operation by any digital modulation method arbitrarily selected from a plurality of digital modulation methods and recognizes a relay operation status by a monitor sound. It is also achieved by providing means for controlling the tone color of the monitor sound according to the error occurrence rate.

A further object of the present invention is to provide a digital modulation wireless relay apparatus of a system which performs a relay operation by any digital modulation method arbitrarily selected from a plurality of digital modulation methods and recognizes a relay operation status by a monitor sound. It is also achieved by providing means for controlling the tone color of the monitor sound according to the equalization residual data in the waveform equalization.

Next, the above object is to provide a digital modulation radio relay apparatus of a system in which relay operation is performed by any digital modulation method arbitrarily selected from a plurality of digital modulation methods and the relay operation status is recognized by a monitor sound. It is also achieved by providing means for switching the intermittent time of the monitor sound with respect to the received signal level according to the selection of the digital modulation method.

Further, the above object is to provide a digital modulation wireless relay apparatus of a system which performs relay operation by any digital modulation method arbitrarily selected from a plurality of digital modulation methods and recognizes the relay operation status by a monitor sound. It is also achieved by providing means for controlling the intermittent time of the monitor sound according to the error occurrence rate.

Further, the above object is to provide a digital modulation wireless relay apparatus of a system which performs a relay operation by any digital modulation method arbitrarily selected from a plurality of digital modulation methods and recognizes a relay operation status by a monitor sound. It is also achieved by providing means for controlling the intermittent time of the monitor sound according to the equalization residual data in the waveform equalization.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION A digital modulation radio relay apparatus according to the present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 shows an embodiment of the present invention. In the figure, reference numeral 70 denotes a received signal detection level switching circuit, and the high frequency unit 1 includes an LNA 2 and a frequency conversion unit 3, SA.
W4, IFAMP5, wave detector 6, VCO9, speaker 1
0, A / D converter 11, CPU 12, D / A converter 13
2 is the same as the conventional device described in FIG.

Therefore, the embodiment of FIG. 1 differs from the prior art of FIG. 2 in that the AMP 7 in the prior art is replaced by the reception signal detection level switching circuit 70.
Here, FIG. 3 shows the received signal detection level switching circuit 70.
In this embodiment, as shown,
DCAMP (DC amplifier) 70A, 70B, 70C
And a changeover switch circuit 70D.

First, DCAMP 70A, 70B,
The 70C inputs the output of the detector 6 in common, and outputs DC voltage signals corresponding to the level of the signal output from the SAW 4 with different gains (gain values) β ₁ , β ₂ , β ₃ (β ₁ ≠ β ₂ ≠
Amplifies and outputs by β ₃ ).

Next, the changeover switch circuit 70D switches the inputs of the three circuits by the selection signal S, and the DCAMP 70A,
The output of one unit selected from the outputs of 70B and 70C is supplied to the VCO 9.

The selection signal S at this time is the high frequency section 1
A relay system including a digital modulation wireless relay device having a function of selecting the switching position of the changeover switch circuit 70D according to the modulation system currently used. It is supplied from the control unit that controls.

As one embodiment of the present invention, in addition to the method of using the received signal detection level switching circuit, the CPU 12 intermittently outputs the monitor sound and changes the intermittent time of the monitor sound according to the level of the received signal R. For example, when the level of the received signal R is low, the intermittent time can be lengthened, and when the level of the received signal R is high, the intermittent time can be shortened.

The intermittent time is determined by the selection signal S.
It is possible to change the set time.

By the way, the C / N-to-BER characteristics of the above various digital modulation systems will be described. It is difficult to easily determine the superiority or inferiority because many parameters are involved. As BPS
When considering K, QPSK, and 16QAM, it can be considered that the BPKS method wins, followed by the QPSK method and 16QAM method.

Then, in the case of the BPSK system, even if the level of the received signal R becomes considerably low, there is no fear that the margin until the reception becomes impossible due to the lowered BER becomes insufficient, and the QPSK system and 16QAM are used. The scheme continues,
This means that the level of the received signal R is successively increasing.

In other words, assuming that the margin until the reception becomes impossible is the same, in the case of the BPSK system, the received signal R
The level of 16 is the lowest, and QPSK and 16
The QAM method will be continued, and therefore, in order to obtain the BL tone of the same tone with the same margin, the DCAMP gain in the BPSK method is set to the maximum, and the QPS
It suffices to reduce the gain sequentially in the K method and the 16QAM method.

Therefore, in this embodiment, each DCAMP is
For the magnitude relationship between the gains β ₁ , β ₂ , and β ₃ of, β ₁ > β ₂
> Set beta _3, assuming this, DCAMP70A gain beta ₁ when the BPSK scheme has been adopted
However, when the QPSK method is adopted, the DCAMP 70B having the gain β ₂ is selected, and when the 16QAM method is adopted, the DCAMP 70C having the gain β ₃ is selected by the changeover switch circuit 70D.

As a result, regardless of which digital modulation method is used at that time, the BL tone changes from the proper tone color when the margin until reception becomes impossible in the digital modulation method becomes the same ( It is possible to obtain a monitor under the same conditions.

Therefore, according to this embodiment, the BER magnitude can be always monitored accurately, and the margin until the BER is lowered and the signal cannot be received can be grasped easily and accurately. Can always be kept high.

In the above embodiment, a plurality of DCAMPs having different gains are used to select them, but a variable gain type DCAMP is used to switch the gains by the selection signal S. However,
In this case, a changeover switch circuit is not necessary and one DCAM
The embodiment of the present invention can be obtained only by P.

When the setting of the intermittent time is changed by the selection signal S, it is determined according to the C / N-BER characteristics of each modulation method. Since the margin for the received electric field strength varies depending on the modulation method as described above, in order to make the same intermittent time with the same margin, when BPSK is selected by the selection signal S, the intermittent time is the longest and 16QAM is selected. In this case, the intermittent time should be the shortest. As a result, it is possible to accurately understand the margin situation in any of the modulation methods.

The above is one embodiment of the present invention in which the level of the received signal R is corrected by the difference in the digital modulation method. Next, another embodiment of the present invention will be described. .

First, as an embodiment of the present invention, an embodiment in which the tone color of the BL tone is changed according to the C / N value in the digital modulation system will be described. In this embodiment, as shown in FIG. In addition, the voltage conversion circuit 14 to which the C / N value is input is used.

Here, the voltage conversion circuit 14 includes the detector 6 and the reception signal level switching circuit 7 in the embodiment of FIG.
The voltage output from the voltage conversion circuit 14 is switched to the VCO 9 and the speaker 10 is provided instead of 0.
To produce a pure tone of a frequency corresponding to the C / N value, which can be monitored.

In the case of this embodiment, when the C / N deteriorates, the pure tone monitored by the speaker 10 falls from the proper sound range such as 400 Hz mentioned above.
It is possible to easily understand that there is no margin in the margin until the reception becomes unreliable and the sufficient monitoring function can be expected.

At this time, the method of detecting the C / N value to be input to the voltage conversion circuit 14 will be described. First, in the first method, a pseudo random signal is generated by the modulator on the transmission side of the digital conversion wireless relay system. There is a method of transmitting a signal at a predetermined timing, receiving the signal, and detecting a pseudo random signal from the demodulated signal.

In the case of this method, the error bit generated in the received pseudo-random signal represents the deterioration of C / N. Therefore, the number of error bits may be integrated and the integrated value may be used as the input data of the voltage conversion circuit 14. In this case, the same tone color may be used even if the digital modulation method is different.

Next, in such a digital repeater-modulation wireless relay apparatus, a waveform equalizer is often used. Therefore, as a second method, when a waveform equalizer is used, there is a method in which the residual difference data ER of the waveform equalizer is used as the C / N value to be input to the voltage conversion circuit 14.

That is, in the waveform equalizer, C due to noise is
The deterioration of / N cannot be equalized. Therefore, if there is noise, the equalization residual data ER will appear, but in this case, its magnitude can be regarded as a C / N value in an equalization manner.

Therefore, this equalization residual data ER is detected,
By inputting the voltage into the voltage conversion circuit 14, it is possible to easily grasp that the margin until the reception becomes impossible due to the lowered BER is likewise easily obtained, and a sufficient monitor function can be expected.

Next, such a digital repeater-modulation radio relay apparatus is often provided with an error correction function. Therefore, as a third method, if an error correction function is provided, B is calculated from the integrated value of the error bit number corrected by this and the error bit number that could not be corrected.
There is a method of calculating the ER and inputting this BER value to the VCO 9.

In the case of the third method, the voltage conversion circuit 14 in the embodiment of FIG. 4 is not necessary, and the above integrated value may be input to the VCO 9 as it is, and at this time, the BL tone directly The deterioration of BER can be monitored.

[0052]

According to the present invention, even if the present invention is applied to a wireless repeater of the digital demodulation system, the monitor function by the BL tone can be sufficiently exerted, and the transmission line margin can always be grasped. The relay operation with high reliability can be easily maintained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a digital re-modulation wireless relay device according to the present invention.

FIG. 2 is a block diagram showing an example of a wireless relay device of a BL tone monitor system according to a conventional technique.

FIG. 3 is a block diagram showing an example of a received signal detection level switching circuit according to an embodiment of the present invention.

FIG. 4 is a block diagram showing an example of a voltage conversion circuit according to another embodiment of the present invention.

[Explanation of symbols]

1 Reception high-frequency section 2 LNA (Low noise amplifier) 3 Frequency converter 4 SAW (surface acoustic wave filter) 5 IFAMP (intermediate frequency amplifier) 6 detector 7 amplifier 9 VCO (voltage controlled oscillator) 10 speakers 11 A / D converter 12 CPU 13 D / A converter 70 Received signal level switching circuit 14 Voltage conversion circuit 70A, 70B, 70C DCAMP (DC amplifier) 70D changeover switch circuit

Claims (6)

[Claims] 1. A relay operation is performed by any one of a plurality of digital modulation methods, which is arbitrarily selected.
In a digital modulation wireless relay device of a method of recognizing a relay operation status by a monitor sound, a means is provided for switching a tone color of the monitor sound with respect to the received signal level according to selection of the digital modulation method. Digitally modulated wireless repeater. 2. The relay operation is performed by any one of a plurality of digital modulation methods selected arbitrarily.
A digital modulation wireless relay device for recognizing a relay operation status by a monitor sound, comprising means for controlling the tone color of the monitor sound according to an error occurrence rate. 3. Relay operation by any digital modulation method arbitrarily selected from a plurality of digital modulation methods,
A digital modulation wireless relay device of a method of recognizing a relay operation status by a monitor sound, characterized in that a means for controlling a tone color of the monitor sound according to equalization residual data in waveform equalization is provided. Wireless relay device. 4. A relay operation by any one of a plurality of digital modulation methods selected arbitrarily.
In a digital modulation wireless relay device of a method of recognizing a relay operation status by a monitor sound, a means is provided for switching an intermittent time of the monitor sound with respect to the received signal level according to selection of the digital modulation method. Digital modulation wireless relay device. 5. Relay operation by any one of a plurality of digital modulation systems selected arbitrarily
A digital modulation wireless relay device for recognizing a relay operation status by a monitor sound, wherein a means for controlling the intermittent time of the monitor sound according to an error occurrence rate is provided. 6. Relay operation by any one of a plurality of digital modulation systems selected arbitrarily
In a digital modulation wireless relay device of a method of recognizing a relay operation status by a monitor sound, a digital means characterized in that means for controlling an intermittent time of the monitor sound according to equalization residual data in waveform equalization is provided. Modulation wireless relay device.