JPH04267642A - Data line defect alarm circuit - Google Patents

Abstract

PURPOSE:To improve the data transmission efficiency by refering to an incoming call electric field value and a time so as to decide the propriety of data transmission with respect to the data line defect alarm circuit used for data transmission by using a narrow band mobile radio line. CONSTITUTION:When a detection section 12 detects it that a DC voltage sent from an incoming electric field monitor section 111 is a preset threshold level or below, the section 12 sends the result of detection to a measurement section 13. When the section 13 measures it that the result of detection is consecutive for a prescribed time or over, the measurement section 13 sends the result of measurement of a data line defect to a display section 14, in which the result is displayed. A preset data transmission propriety criterion is stored in a memory section 23. A deciding section 22 digitizes the DC voltage outputted from the incoming electric field monitor section 111 and compares it with the data transmission propriety criterion from the memory to decide the data transmission propriety. When the result of decision indicates the data transmission negation, the result of decision of data line defect is sent to the display section 14, in which the result is displayed. When the deciding section 22 decides the data transmission negation, a gate section 24 is turned off based on the result of decision to prevent a base band signal from being fed to a transmission section 21.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data line failure alarm circuit used, for example, when transmitting data using a narrowband mobile radio line.

Conventionally, narrowband radio lines using a single channel (hereinafter referred to as "single radio") have mainly transmitted analog information such as voice, but in recent years data transmission has become more common.

[0003] The problem when transmitting data using a single radio is that one of the radio stations transmitting data is often a mobile device, so it is expected that there will be large changes in the electric field strength. Ru.

[0004] Here, whether or not a wireless line is suitable for data transmission has been determined only from the value of the incoming electric field. For this reason,
Even if the voltage momentarily falls below the threshold, it is displayed as a faulty line and the use of the line is prohibited, resulting in a decrease in data transmission efficiency and inconvenience.

[0005] Therefore, it is necessary to improve the data transmission efficiency by determining whether the data line is defective by referring to the incoming electric field and time.

[0006]

2. Description of the Related Art FIG. 8 is a block diagram of a receiver. This receiver is used, for example, for narrowband radio links with a single channel. The operation of FIG. 8 will be explained below.

First, for example, a signal in the 800 MHz band is input to the high frequency amplifier A1 via an antenna and a band pass filter BPF1. The high frequency amplifier A1 amplifies the received signal and sends it to the mixer MI via the band pass filter BPF2.
Send to X1.

[0008] The mixer MIX1 includes a first receiving local oscillator.
Since the first local oscillator signal from OSC1 is also applied, 8
The received signal in the 00 MHz band is frequency-converted to a received signal in the first intermediate frequency band (for example, a specified frequency within the 70-90 MHz band).

[0009] After removing unnecessary wave components from the received signal in the first intermediate frequency band by a band pass filter BPF3, the received signal is sent to a mixer MIX.
2, the signal is mixed with the second local oscillator signal from the second receiving local oscillator OSC2 to generate a second intermediate frequency band (e.g., 455 KHz).
frequency converted to the received signal.

[0010] Then, the received signal in the second intermediate frequency band has unnecessary wave components removed by the band pass filter BPF4, and then is amplified to a predetermined level by the amplifiers A2 and A3 in the second intermediate frequency band, and then sent to the frequency discriminator DISC. Added.

After the frequency discriminator DISC performs frequency discrimination and extracts the baseband signal, the de-emphasis circuit D
Add to E. This circuit DE has characteristics opposite to the 6 dB/octave emphasis circuit (not shown) on the transmitting side, so the emphasis characteristics are compensated and a baseband signal with frequency characteristics within the specified range is extracted, and the switch SW, drives the speaker SP via the baseband amplifier A5.

Note that the output level of the second intermediate frequency band amplifier A2 corresponds to the received input level, that is, the incoming electric field level, so it is converted to a DC voltage by the detector D1,
RSSI (Receiving Signal Str
length Indicator) is sent as an output value.

Further, the noise amplifier A4 extracts and amplifies the noise component within a predetermined band from the output of the frequency discriminator, and then applies the DC voltage obtained by detection by the detector D2 as a control voltage to the switch SW. ing.

[0014] Thereby, when the incoming electric field level decreases and the DC voltage exceeds a specified voltage, the switch SW is turned off to prevent the speaker SP from being driven by noise components.

Next, FIG. 9 is a block diagram of a conventional example, and FIG.
9 is an explanatory diagram of the operation in FIG. 9, (A) is a diagram showing an example of the RSSI output value over time, and (B) is an example diagram showing the relationship between the RSSI output value and the electric field strength.

The operation of FIG. 9 will be explained below with reference to FIG. First, the comparator 1 constantly compares the RSSI output value with a set threshold value E1. In addition,
The threshold value E1 is a voltage for determining a line failure, and is a preset value.

Now, when the RSSI output value becomes smaller than the set threshold value E1, the comparator 1 supplies a driving current to the light emitting diode D3 to cause it to emit light, thereby displaying a "line failure alarm". In the case of mobile communications, there is usually no line-of-sight between the mobile device and the base station, so the received wave is a composite of many reflected waves, diffracted waves, etc., and there are standing waves in the space. ing.

[0018] Therefore, as the mobile device travels on this standing wave, the received waves are always subject to fading. The RSSI output value in such a state is, for example, as shown in FIG.
As shown in A), dips occur corresponding to the troughs of the standing wave, but the magnitude of the dips differs depending on the receiving location, as shown in FIG. 10.

[0019] In a data transmission line, normally, when the electric field strength becomes +20 to +30 dB/μV or less,
The line is defective.'' Therefore, if the relationship between the RSSI output value and the electric field strength is as shown in Figure 10 (B),
As shown by the dotted line in the figure, the threshold value is approximately 1.6 to 2.3V.
become.

[0020]

[Problem to be solved by the invention] As mentioned above, RSSI
When the output value fell below a threshold value, a "line failure alarm" was output and displayed, and this alarm prohibited the use of the line.

[0021] Therefore, even a momentary drop in the incoming electric field prohibits the use of the line, resulting in a decrease in data transmission efficiency, which is inconvenient in terms of operation. An object of the present invention is to improve data transmission efficiency by determining whether or not data transmission is possible with reference to the incoming electric field value and time.

[0022]

[Means for Solving the Problems] FIG. 1 is a block diagram of the principle of the first invention, and FIG. 2 is a block diagram of the principle of the second and third inventions.

In the figure, 11 is a receiving section including an incoming electric field monitor section that outputs a DC voltage that changes logarithmically with respect to changes in the incoming electric field value, and 12 is a receiving section that includes an incoming electric field monitor section that outputs a DC voltage that changes logarithmically with respect to changes in the incoming electric field value. , is a detection part that sends out a detection result when it detects that the value is below a set threshold.

Reference numeral 13 denotes a measurement part that sends out the measurement result when it is determined that the detection result continues for a predetermined period of time or more, 14 is a display part that displays the measurement result from the measurement part, and 21 is a display part that displays the measurement result from the measurement part. This is a transmitter that generates a modulated wave using the applied baseband signal and sends it out at a predetermined frequency and predetermined power.

22 digitizes the DC voltage output from the incoming electric field monitor section, and then compares it with the data transmission permission standard from the memory to determine whether data transmission is possible;
In the determination section that sends out the determination results, 23 is a memory section that stores preset criteria for determining whether or not data transmission is possible.

Reference numeral 24 denotes a gate section which operates so that the baseband signal is not applied to the transmitting section when the judgment result sent from the judging section is that data transmission is not possible. And the third
The present invention is configured to transmit information about a data line failure by sending an unmodulated wave to the opposite station.

[0027]

[Operation] In the first aspect of the present invention, when the detection part detects that the DC voltage sent from the incoming electric field monitor part is below a set threshold value, the detection result is sent to the measurement part. .

[0028] When the measurement part measures that the detection result continues for a predetermined period of time or more, the measurement result of data line failure is sent to the display part and displayed there. Second
According to the present invention, preset criteria for determining whether or not data transmission is possible are stored in a memory portion.

[0029] This criterion is, for example, that data transmission is not possible when the time during which the DC voltage is below the threshold value is Δt0 or more, and the time until it becomes below the threshold value is within T0. It's like making a judgment.

Therefore, the determining section digitizes the DC voltage output from the incoming electric field monitor section, and then compares it with the criterion for determining whether data can be transmitted from the memory to determine whether or not data can be transmitted.

When the determination result is that data transmission is not possible, the determination result of data line failure is sent to the display section and displayed there. In the third aspect of the present invention, when the determination section determines that data transmission is not possible as described above, the gate section is turned off based on the determination result so that the baseband signal is not applied to the transmitting section.

[0032] As a result, the unmodulated wave is sent to the opposite station, and the opposite station receives the unmodulated wave and obtains information about a data line failure. In other words, whether or not data transmission is possible is determined by referring to the time during which the incoming electric field level is below the threshold value and the elapsed time until it becomes below the threshold value again. Efficiency can be improved.

[0033]

[Embodiment] FIG. 3 is a block diagram of an embodiment of the first invention.
4 is an explanatory diagram of the operation of FIG. 3, FIG. 5 is a block diagram of the second embodiment of the present invention, and FIG. 6 is an explanatory diagram of the operation of FIG.

FIG. 7 is a block diagram of the third embodiment of the present invention. In order to send an unmodulated wave to the opposite station, (A) shows that the data transmission permission signal sent by the modem is not applied to the terminal. (B) is a case in which the baseband signal from the modem is not applied to the transmitter.

Here, the comparator 121 and the inverter 122
is a component of the detection portion 12, the counter 131 is a component of the measurement portion 13, and the display circuit 141 is a component of the display portion 14.
It is a component of Further, the analog/digital converter 221 and the CPU 222 are components of the determination section 22, the memory 231 is a component of the memory section 23, and the AND
Gate 241 and mute circuit 242 are gate part 2
It is a constituent part of 4.

Note that the same reference numerals indicate the same objects throughout the figures. Hereinafter, FIGS. 3 to 7 will be explained. First, the operation of FIG. 3 will be explained with reference to FIG.

Since the RSSI output value from the incoming electric field monitor section (not shown) and the threshold value E1 are applied to the comparator 121, the RSSI output value and the threshold value E1 are always applied to the comparator 121.
I am comparing the size with 1.

Now, as shown in FIG. 4, at a certain time RSS
If the I output value falls below the threshold E1, '1' is applied from the comparator 121 to the counter 131 as an enable signal.

The counter 131 starts a counting operation, and when it continues to operate for a period of Δt0, for example, it sends out a count output '1' indicating whether data transmission is not possible to the display circuit 141, so that the display circuit 141 corresponds to '1'. "Data line failure" is displayed.

[0040] Note that Δt0 is a preset standard for determining whether data transmission is not possible, and the operating time of the counter is Δt0.
If it is smaller than , it is not determined that data transmission is not possible. but,
As shown in Figure 4, Δt1 (Δt1≧Δt0) time,
When the RSSI output value becomes larger than the threshold value E1, the output of the comparator 121 changes to '0', but this is applied to the reset terminal of the counter via the inverter 122, so this The counter returns to its initial state and the display on the display circuit also disappears.

Next, the operation of FIG. 5 will be described with reference to FIG. First, the memory 231 stores preset criteria for determining whether or not data transmission is possible. This criterion is, for example, RS
It is predetermined in advance that data transmission is determined to be impossible when the time during which the SI output value is below the threshold E1 is greater than or equal to Δt0, and the time until it becomes below the threshold next is less than or equal to T0. .

Now, the RSSI from the incoming electric field monitor part
The output value is converted into a digital value by an analog/digital converter 221 and then applied to the CPU 222 . The CPU compares the applied digitized RSSI output value with the digitized threshold value E1, and when it detects that the former is lower than the latter, the decreasing time is Δt.
Compare whether it is longer than 0.

When it is detected that this time is Δt2, which is longer than Δt0, it is then detected again whether the time taken to fall below the digitization threshold E1 is longer or shorter than T0. This is shorter than T0
1, it is determined that data transmission is not possible based on the above determination criteria, and the determination result is sent to the display circuit.

Therefore, the display circuit displays "data line failure" and the CPU repeats the above-described determination operation. Note that the judgment is made by comparing the time during which the digitization threshold value E1 is lower than the digitization threshold value E1, and the time until the digitization threshold value E1 is lower than the digitization threshold value E1 again, compared only once with the judgment criteria. The determination may be made after repeating multiple times.

Further, the operation of FIG. 7 will be explained. Note that the operations indicated by dotted lines in the figure are the same as those in FIG. 5, and therefore will be omitted. First, in the case of (A) in FIG. 7, when data transmission is possible, the CPU 222 AND gate 241
This gate is in the on state.

On the other hand, when the modem 26 sends data,
From here, send the transmission permission signal CS to the data terminal equipment (DTE)
25, this signal CS is applied to DTE through an AND gate.

[0047] Therefore, data is sent from the DTE to the modem 26.
Here, data '1' is converted to a baseband signal of frequency f1 and data '0' is converted to a baseband signal of frequency f2, and then the carrier is modulated by the radio transmitter 21 and sent from the antenna duplexer 212 to the other party. Send to.

However, when the CPU 222 determines that data transmission is not possible, it sends '0' to the AND gate, so the transmission permission signal from the modem is not sent to the data terminal device. As a result, data is not sent from the data terminal device to the modem, so that an unmodulated wave is sent from the transmitter to the other station, and information about a data line failure can be transmitted.

Next, in the case of (B) in FIG. 7, similarly to (A), the CPU 222 normally switches
42, this circuit is turned on,
The modem and the wireless transmitter are in a connected state.

However, when the CPU 222 determines that data transmission is not possible, it sends '0' to the mute circuit 242, so this circuit is turned off and the connection between the modem and the radio transmitter 21 is disconnected. . Therefore, since data is not sent from the data terminal device to the modem, an unmodulated wave is sent from the transmitter to the other station, and information about a data line failure can be transmitted.

That is, since it is determined whether or not data transmission is possible with reference to the incoming electric field value and time, data transmission efficiency can be improved.

[0052]

[Effects of the Invention] As explained in detail above, according to the present invention,
By determining whether or not data transmission is possible with reference to the incoming electric field value and time, there is an effect that data transmission efficiency can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the principle of the first invention.

FIG. 2 is a principle block diagram of the second and third aspects of the present invention.

FIG. 3 is a block diagram of the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of the operation in FIG. 3;

FIG. 5 is a block diagram of a second embodiment of the present invention.

FIG. 6 is an explanatory diagram of the operation in FIG. 5;

FIG. 7 is a block diagram of the third embodiment of the present invention, in which (A) the data transmission permission signal sent by the modem is not applied to the terminal in order to send out non-modulated waves; (B)
This is the case when the baseband signal from the modem is not applied to the transmitter.

FIG. 8 is a block diagram of a receiver. This receiver is used, for example, for narrowband radio links with a single channel.

FIG. 9 is a block diagram of a conventional example.

FIG. 10 is an operation explanatory diagram of FIG. 9, in which (A) shows an example of the RSSI output value over time, and (B) shows R
It is a figure which shows an example of the conversion table of an SSI output value and electric field strength.

[Explanation of symbols]

Claims (3)

[Claims] Claim 1: An incoming electric field monitor portion (111
), and a transmitter (21) that generates a modulated wave using an applied baseband signal and transmits it at a predetermined frequency and with a predetermined power, and performs data transmission. , a detection part (12) that sends out a detection result when it detects that the DC voltage sent out from the incoming electric field monitor part is below a set threshold; A data line fault alarm circuit comprising a measurement part (13) that sends out a measurement result when measuring continuity, and a display part (14) that displays the measurement result from the measurement part. 2. In the wireless device according to claim 1, after digitizing the DC voltage output from the memory portion (23) storing preset data transmission permission/denial criteria and the incoming electric field monitor portion. , a determination part (22) that determines whether or not data can be transmitted by comparing it with the data transferability standard from the memory and sends out the determination result, and a display part (14) that displays the determination result from the determination part. A data line failure alarm circuit characterized by: 3. A gate section (24) is provided that operates so that the baseband signal is not applied to the transmitting section when the judgment result sent from the judgment section is that data transmission is not possible, and the non-modulated wave is sent to the opposing station. 3. The data line failure alarm circuit according to claim 2, wherein the data line failure alarm circuit is configured to transmit information about a data line failure.