JP3229725B2 - Digital modulation wave monitoring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for monitoring a digitally modulated wave generated by performing a differential logic conversion in a radio transmission apparatus, and more particularly to a method for monitoring a digitally modulated wave which has been subjected to processing such as phase modulation and quadrature amplitude modulation. About the method.

2. Description of the Related Art Conventionally, in a radio transmission apparatus for transmitting data by digital modulation, a data processing state in the transmission apparatus is monitored in order to maintain the quality of a circuit in the apparatus.

[0003]

2. Description of the Related Art FIG. 14 is a block diagram showing a schematic configuration of a conventional transmitting apparatus. Here, 4P with a spare circuit
The SK transmission device will be described. The working line includes a digital processing circuit 81a, a digital modulation circuit 82a,
A transmission circuit 83a, a pulse monitor 84a, and an output monitor 85a are provided. On the other hand, as a protection line,
Similarly, a digital processing circuit 81b, a digital modulation circuit 82b, a transmission circuit 83b, a pulse monitor 84b, and an output monitor 85b are provided.

When the working line is used, data processed by the digital processing circuit 81a is phase-modulated by the digital modulation circuit 82a, amplified by the transmission circuit 83a, and output through the changeover switch 87. The pulse monitor 84a constantly monitors the data pulse input to the digital processing circuit 81a, and sends an abnormality detection signal to the alarm / switch control unit 86 when an abnormality is detected in the pulse output value. The output monitor 85a detects the output level of the digital modulation wave output from the transmission circuit 83a, and sends an abnormality detection signal to the alarm / switch control unit 86 when the output level falls below a predetermined value.

[0005] The alarm / switch control unit 86 includes a pulse monitor 8.
When receiving the abnormality detection signal from the output monitor 4a or the output monitor 85a, the switching instruction signal is sent to the changeover switch 87. At this time, the alarm / switch control unit 86 gives an alarm to the operator by emitting light from an LED or the like. The changeover switch 87 normally outputs a digital modulation wave from the transmission circuit 83a on the working line side, and switches to a protection line when a changeover command signal is input. Each circuit on the protection line performs the same operation as that on the working line. When the connection is switched to the protection line, the digital modulation wave from the transmission circuit 83b of the protection line is output via the switch 87.

As described above, the abnormality in the transmitter can be detected by the pulse monitor 84a, the output monitor 85a, etc., and the countermeasure can be taken promptly.

[0007]

However, in such a conventional transmitter, the output level of the digital modulation wave can be monitored by the output monitors 85a and 85b, but the quality of the spectrum cannot be monitored. Did not. Hereinafter, this will be described.

FIG. 15 is a diagram showing a specific configuration of a portion related to digital modulation processing in the configuration of FIG.
In the digital processing circuit 81a, the input binary data is received by a serial / parallel converter (S / P) 811,
The signals are distributed one bit at a time, and are sent to speed conversion circuits (SPD) 812a and 812b, respectively. The data processed by the speed conversion circuits 812a and 812b are sent to scramblers 813a and 813b, respectively. The scramblers 813a and 813b randomize the data sequence and send it to the differential logic conversion circuit 821 of the digital modulation circuit 82a.

The differential logic conversion circuit 821 adds the present data to the previous data and outputs the result as phase data.
The D / A conversion circuits 822a and 822b convert the digital data into analog data and apply a low-pass filter (L
PF) 823a and 823b. The data that has passed through the low-pass filter 823a is sent to the ring modulator 824a as I-channel data, while the data that has passed through the low-pass filter 823b is sent to the ring modulator 824b as Q-channel data.

Each digitally modulated wave generated by the ring modulators 824a and 824b is a hybrid (H) 825
And output to the transmission circuit 83a. by the way,
Digital modulation circuit 8 having differential logic conversion circuit 821
The spectrum of the digital modulation wave generated by 2a is abnormal due to a failure of a part of the circuit.

FIGS. 16A and 16B are diagrams showing the characteristic shape of the spectrum of the output section, wherein FIG. 16A is a characteristic diagram at the time of failure in the N1 stage, FIGS. 16B and 16C are characteristic diagrams at the time of failure at the N2 stage. (D) and (E) are characteristic diagrams at the time of failure in the N3 stage. When there is an abnormality in the N1 stage,
If one of the speed control circuits 812a or 812b fails and its output is always fixed at 1 or 0, the spectrum of the digital modulation wave has a waveform as shown in FIG. This holds the reference level value r and has the same form as in the normal state. Therefore, this abnormality cannot be detected by the output monitor 85a or the like. However, since the pulse monitor 84a is provided at the output of the speed control circuits 812a and 812b, it is possible to detect an abnormality at the N1 stage.

FIG. 2B shows, for example, a scrambler 813a.
Is a spectrum in the case where a failure occurs and the output is always fixed to 1 or 0. On the other hand, FIG.
13b is a spectrum in the case where the output 13b is fixed to 1 or 0 due to a failure. The failure of the scrambler 813a, displaced by Delta] f ₁ also e.g. on the left side than the frequency f _o of the center level apex portion of the spectrum. Also, the level value of the vertex part is larger than the reference level value r by Δr ₁ . On the other hand, when the scrambler 813b fails,
The peak portion of the spectrum level is shifted from the center frequency by, for example, Δf _{2 to the} right. Also, the level value of the vertex portion is larger than the reference level value r by Δr ₂ . Here, each value f _o , Δf ₁ , Δf ₂ , Δr ₁ , Δr ₂ is
When the input data is, for example, 34 Mb / s, 70 MHz, 2.2 MHz, 2.2 MHz, 7 dB, 7
dB.

It is known that the phenomena shown in FIGS. 1B and 1C are caused by the processing of the differential logic conversion circuit 821 in the digital modulation circuit 82a. FIG. 4D shows a spectrum when one of the pulses of the I channel and the Q channel is fixed to 1 or 0 in the N3 stage. This is because, for example, the D / A conversion circuits 822a and 822a
Occurs when one of 2b fails. In this case, although the level value is generally lower than the reference level value r, a large carrier Ca is generated at the center.

FIG. 3E shows the D / A conversion circuits 822a and 82a.
2b is a spectrum when one of the I-channel and Q-channel outputs is completely turned off due to a failure, and the total sum of the outputs is half that in the normal state.

In the abnormalities shown in FIGS. 3B to 3D, since the sum of the output levels is almost the same as the normal value, the output monitor 85
It is not possible to detect an abnormality in the spectrum only by a. Further, even in the case of an abnormality as shown in FIG. 9E, the abnormality cannot be detected unless the position of the output monitor 85a is placed immediately after the digital modulation circuit.

As described above, conventionally, the differential logic conversion circuit 8
If an abnormality occurs in the spectrum waveform of the digitally modulated wave processed in step 21, the transmission device cannot detect it, so the abnormality was detected only after the reception device received the signal. Therefore, until the notification of the abnormality detection is received from the receiving side, the transmitting side cannot deal with it, and the processing such as automatic switching to the standby circuit cannot be performed quickly.

The present invention has been made in view of such a point, and an object of the present invention is to provide a digital modulation wave monitoring method capable of easily detecting an abnormal waveform of a spectrum on a transmitting device side.

[0018]

FIG. 1 is a diagram showing the principle of a digital modulation wave monitoring system according to the present invention which achieves the above object. According to the present invention, in a method of monitoring a digital modulation wave generated by a wireless transmission device, a digital modulation circuit 1 that performs differential logic conversion of input data to convert the data into a digital modulation wave, and a frequency spectrum of the digital modulation wave A modulated wave monitor 2 for detecting a waveform abnormality, an alarm processing means 3 for performing an alarm process when the waveform abnormality is detected, and a transmission circuit 4 for outputting the digital modulated wave to a receiving side. .

[0019]

The digital modulation circuit converts the input data into a digital modulation wave by performing a differential logic conversion, and sends the digital modulation wave to the transmission circuit. The transmission circuit 4 outputs this digitally modulated wave to the receiving side. The modulated wave monitor 2 detects an abnormality in the waveform of the frequency spectrum of the digitally modulated wave, and when this waveform abnormality is detected, the alarm processing means 3 performs an alarm process.

If there is an abnormality in the preceding stage of the differential logic conversion of the digital modulation circuit 1, the digitally modulated wave subjected to the differential logic conversion causes a distortion in its spectrum waveform.
By detecting this with the modulated wave monitor 2, an abnormality can be easily detected on the transmission device side.

[0021]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing a schematic configuration of the transmitting apparatus according to the first embodiment of the present invention. Here, a 4PSK transmission device including a backup circuit will be described. As the working line, a digital processing circuit 11a, a digital modulation circuit 12a, a transmission circuit 13a, a pulse monitor 14a, an output monitor 15a, and a modulation wave monitor 16a are provided. On the other hand, as the backup circuit, the digital processing circuit 11b, the digital modulation circuit 12b, the transmission circuit 13b, the pulse monitor 14b, the output monitor 15b,
And a modulated wave monitor 16b.

When the working line is used, the data processed by the digital processing circuit 11a is phase-modulated by the digital modulation circuit 12a, amplified by the transmission circuit 13a, and output through the changeover switch 18. The pulse monitor 14a constantly monitors the data pulse input to the digital processing circuit 11a, and sends an abnormality detection signal to the alarm / switch control unit 17 when an abnormality is detected in the pulse output value. The output monitor 15a detects the output level of the digital modulation wave output from the transmission circuit 13a, and sends an abnormality detection signal to the alarm / switch control unit 17 when the output level falls below a predetermined value.

The modulation wave monitor 16a constantly monitors the digital modulation wave modulated by the digital modulation circuit 12a, and detects a spectrum abnormality by a method described later. When an abnormality is detected, an abnormality detection signal is sent to the alarm / switch control unit 17.

The alarm / switch control unit 17 includes the pulse monitor 1
When an abnormality detection signal is received from any one of the output monitor 4a, the output monitor 15a, and the modulated wave monitor 16a, a switch command signal is sent to the switch 18. Further, at this time, the alarm / switch control unit 17 gives an alarm to the operator by emitting light of an LED or the like. The changeover switch 18 normally outputs a digital modulation wave from the transmission circuit 13a on the working line, and switches to a protection line when a changeover command signal is input. Each circuit on the protection line performs the same operation as that on the working line. When switching to the protection line, the digital modulation wave from the transmission circuit 13b of the protection line is switched to the changeover switch 18
Is output via.

FIG. 3 is a block diagram showing the configuration of the modulated wave monitor 16a. The modulated wave monitor 16 on the protection line side
Since the configuration of b is the same as the configuration of the modulated wave monitor 16a, the description is omitted. The modulated wave monitor 16a mainly includes
Bandpass filter (BPF) 21, detection / smoothing circuit 2
2 and a level detection circuit 23.

The band-pass filter 21 extracts and outputs only the intermediate frequency band from the input digital modulated wave. The detection / smoothing circuit 22 detects and smoothes the digitally modulated wave. The level detection circuit 23 detects an abnormality in the spectrum of the digital modulation wave by level detection described later, and outputs an abnormality detection signal.

FIG. 4 is a diagram showing an example of the configuration of the band-pass filter 21. In the band-pass filter 21, a resonance circuit including a transformer (T) 21a and a capacitor (C) 21b and a resonance circuit including a transformer (T) 21d and a capacitor (C) 21c are combined with a coupling capacitor (Cc) 21e. It is constituted by being connected by.

FIG. 5 is a diagram showing the spectrum characteristics of the digital modulation wave passed through the band-pass filter 21. In FIG. Here, a spectrum having the same shape as that shown in FIG. 17B is taken as an example. The digital modulation circuit 12a of the present embodiment, the center frequency f _o when the input data is 34 Mb / s will be 70 MHz. The cut-off frequencies f _a and f _b on both sides at this time are, for example, 66 MHz, respectively.
Set to z and 74 MHz. Thereby, the peak P of the spectrum falls within the level detection area.

The digitally modulated wave processed by the band-pass filter 21 is sent to a level detection circuit 23 via a detection / smoothing circuit 22, where the level is detected. The level detection circuit 23 determines the level of the spectrum using the preset high-level set value and low-level set value. The high level set value and the low level set value are each, for example, + 2d compared to the level of the normal value.
B, -2 dB.

The level detecting circuit 23 detects the level of the spectrum for each frequency, and compares the detected level with the high level set value and the low level set value. If the level of a part of the spectrum is higher than the high level setting value or lower than the low level setting value, the level detection circuit 23 sends an abnormality detection signal to the alarm / switch control unit 17. In the case of the spectrum shown in FIG. 5, the vicinity of the vertex P surely exceeds the high level set value, so that an abnormality can be easily detected. Here, an example of the spectrum having the vertex P on the left side is shown, but the level detection is similarly performed for the spectrum having the vertex P on the right side shown in FIG. Can be.

By appropriately changing the numerical value setting, it is possible to detect the level of the spectrum having the carrier Ca shown in FIG. In this case, since the portion of the carrier Ca exceeds the high level set value, an abnormality can be detected.

Further, in the spectrum shown in FIG. 16 (E), since the level value is lower than the low level set value at all frequencies, an abnormality can be easily detected.

As described above, in the present embodiment, only the spectrum near the intermediate frequency of the digital modulation wave is extracted by the band-pass filter 21, and the level value of the spectrum is compared with the high level setting value and the low level setting value. Therefore, it is possible to easily detect a spectrum abnormality on the transmission device side.

Next, a second embodiment of the present invention will be described. FIG. 6 is a diagram showing the configuration of the second embodiment of the present invention. This embodiment is an example of a 4PSK transmission device as in the first embodiment. However, here, an example is shown in which the present invention is applied to a transmission system without a protection line. Circuits having the same functions as those in FIG. 2 will be described with the same reference numerals.

The data processed by the digital processing circuit 11a is phase-modulated by the digital modulation circuit 12a, amplified by the transmission circuit 13a and output. Pulse monitor 1
4a constantly monitors the data pulse input to the digital processing circuit 11a, and sends an abnormality detection signal to the alarm processing unit 19 when an abnormality is detected in the pulse output value. The output monitor 15a detects the output level of the digital modulation wave output from the transmission circuit 13a, and when the output level falls below a predetermined value, outputs an abnormality detection signal to the alarm processing unit 19
Send to

The modulation wave monitor 16a has substantially the same configuration as the modulation wave monitor shown in FIG. 3, and constantly monitors the digital modulation wave modulated by the digital modulation circuit 12a. Detect abnormalities. When an abnormality is detected, an abnormality detection signal is sent to the alarm processing unit 19. Upon receiving the abnormality detection signal, the alarm processing unit 19 performs an alarm display or the like according to the content.

The present embodiment can also be applied to a transmission system having one protection line for a plurality of working lines. Next, a third embodiment of the present invention will be described.

FIG. 7 is a diagram showing the configuration of the third embodiment of the present invention. Here, an example of a 16QAM transmitting apparatus including a backup circuit will be described. The working line includes a digital processing circuit 31a, a digital modulation circuit 32a, a transmission circuit 3a.
3a, a pulse monitor 34a, an output monitor 35a, and a modulated wave monitor 36a are provided. On the other hand, as a backup circuit, the digital processing circuit 31
b, a digital modulation circuit 32b, a transmission circuit 33b, a pulse monitor 34b, an output monitor 35b, and a modulation wave monitor 36b.

When the working line is used, the data processed by the digital processing circuit 31a is subjected to quadrature amplitude modulation by the digital modulation circuit 32a, amplified by the transmission circuit 33a, and output through the switch 38. The pulse monitor 34a constantly monitors the data pulse input to the digital processing circuit 31a, and when an abnormality is detected in the pulse output value, outputs an abnormality detection signal to the alarm / switch control unit 3.
Send to 7. The output monitor 35a detects the output level of the digital modulation wave output from the transmission circuit 33a, and sends an abnormality detection signal to the alarm / switch control unit 37 when the output level exceeds a predetermined limit value.

The modulated wave monitor 36a has the same configuration as the modulated wave monitor shown in FIG.
The digitally modulated wave modulated in step (1) is constantly monitored, and a spectrum abnormality is detected by the method described above. If an abnormality is detected, an abnormality detection signal
This is sent to the switching control unit 37.

The alarm / switch control unit 37 includes the pulse monitor 3
When an abnormality detection signal is received from any of the output monitor 4a, the output monitor 35a, and the modulated wave monitor 36a, the switching command signal is sent to the switch 38. Further, at this time, the alarm / switch control unit 37 gives an alarm to the operator by emitting light of an LED or the like. The switch 38 normally outputs a digital modulation wave from the transmission circuit 33a on the working line, and switches to a protection line when a switch command signal is input. Each circuit on the protection line performs the same operation as that on the working line. When switching to the protection line, the digital modulation wave from the transmission circuit 33b of the protection line is switched to the changeover switch 38.
Is output via.

The digital processing circuits 31a and 31b of this embodiment are provided with a path switching circuit.
Switching of data processing is performed simultaneously according to a switching command signal from the path control circuit 30. The path control circuit 30 outputs a switching command signal according to a switching command periodically sent from the outside.

FIG. 8 is a diagram showing the internal configuration of the digital processing circuit 31a and the digital modulation circuit 32a.
In the digital processing circuit 31a, the input binary data is received by the serial / parallel converter (S / P) 311.
The data is distributed to 4 bits in parallel and sent to the scrambler 312. Data output from the serial / parallel converter 311 is output as two paths 1 and 2 of the I channel and two paths 1 and 2 of the Q channel. Path 1 is the large amplitude data MSB in each channel, while path 2 is the small amplitude data LSB in each channel. The scrambler 312 randomizes each data sequence and sends it to the pulse switching circuit 313.

The pulse switching circuit 313 is a circuit for switching the destination of the data of the path 1 and the path 2 of each channel. The pulse switching circuit 313 normally sends only the data of the path 1 for both the I channel and the Q channel to the differential logic conversion circuit 321 of the digital modulation circuit 32a.
On the other hand, the data on the path 2 is sent to the D / A conversion circuit 322 without passing through the differential logic conversion circuit 321. Then, the destinations of the path 1 and the path 2 are temporarily switched at the input timing of the switching command signal from the path control circuit 30 described above. The information of the switching control is included in the digital modulation wave and sent to the receiving device side, and the path 1 and the path 2 are switched and demodulated at the same timing, so that the digital is reliably reproduced. .

The differential logic conversion circuit 321 adds the current data to the previous data and outputs the result as phase data.
The D / A conversion circuit 322 converts digital data into analog data and sends the data to the modulation circuit 323, respectively. The modulation circuit 323 digitally modulates and outputs these data.

The digitally modulated wave output in this way is abnormally detected by the modulated wave monitor 36a. As described above, only the data processed by the differential logic conversion circuit 321 contributes to the shape of the spectrum. Therefore, normally, only the data of the path 1 in which both the I channel and the Q channel are MSBs are involved. That is, when there is an abnormality in the spectrum, only the circuit relating to the data of the path 1 can know the failure. However, in this embodiment, since the destination of the path 1 and the path 2 of each channel is temporarily switched by the pulse switching circuit 313, an abnormality relating to the path 2 can be detected.

Next, a fourth embodiment of the present invention will be described. FIG. 9 is a diagram showing the configuration of the fourth embodiment of the present invention. This embodiment is an example of a 16QAM transmitting apparatus as in the third embodiment. However, here, an example is shown in which the present invention is applied to a transmission system without a protection line. In addition, circuits having the same functions as those in FIG.

The data processed by the digital processing circuit 31a is subjected to quadrature amplitude modulation by the digital modulation circuit 32a, amplified by the transmission circuit 33a, and output. Further, the digital processing circuit 31a switches the destination of the path 1 and the path 2 of each channel in accordance with the switching command signal from the path control circuit 30. The specific contents are as shown in FIG.

The pulse monitor 34a constantly monitors the data pulse input to the digital processing circuit 31a, and sends an abnormality detection signal to the alarm processing section 39 when an abnormality is detected in the pulse output value. The output monitor 35a detects the output level of the digital modulation wave output from the transmission circuit 33a, and sends an abnormality detection signal to the alarm processing unit 39 when the output level exceeds a predetermined limit value.

The modulation wave monitor 36a has the configuration shown in FIG. 3, and constantly monitors the digital modulation wave modulated by the digital modulation circuit 32a, and detects an abnormality in the spectrum by the method described above. When an abnormality is detected, an abnormality detection signal is sent to the alarm processing unit 39. Upon receiving the abnormality detection signal, the alarm processing unit 39 performs an alarm display or the like according to the content.

The present embodiment can also be applied to a transmission system having one protection line for a plurality of working lines. Next, a fifth embodiment of the present invention will be described.

FIG. 10 is a diagram showing the configuration of the fifth embodiment of the present invention. Here, an example of an 8PSK transmission device provided with a backup circuit will be described. The working line includes a digital processing circuit 41a, a digital modulation circuit 42a, a transmission circuit 4a.
3a, a pulse monitor 44a, an output monitor 45a, a modulated wave monitor 46a, and an IQ level difference detection circuit 49a are provided. On the other hand, as a spare circuit, a digital processing circuit 41b, a digital modulation circuit 42b, a transmission circuit 43b, a pulse monitor 44b, an output monitor 45b, a modulated wave monitor 46b, and an IQ level difference detection circuit 49b are provided as in the working line. Have been.

When the working line is used, the data processed by the digital processing circuit 41a is phase-modulated by the digital modulation circuit 42a, amplified by the transmission circuit 43a, and output via the switch 48. The pulse monitor 44a constantly monitors the data pulses input to the digital processing circuit 41a, and sends an abnormality detection signal to the alarm / switch control unit 47 when an abnormality is detected in the pulse output value. The output monitor 45a detects the output level of the digital modulation wave output from the transmission circuit 43a, and sends an abnormality detection signal to the alarm / switch control unit 47 when the output level falls below a predetermined value.

The modulated wave monitor 46a has the same configuration as the modulated wave monitor shown in FIG.
The digitally modulated wave modulated in step (1) is constantly monitored, and a spectrum abnormality is detected by the method described above. If an abnormality is detected, an abnormality detection signal
This is sent to the switching controller 47.

The IQ level difference detection circuit 49a is a circuit for detecting an abnormal level difference between the I channel and the Q channel in the digital modulation circuit 42a. When an abnormality is detected, an abnormality detection signal is sent to the alarm / switch control unit 47. The details will be described later.

The alarm / switch control unit 47 includes the pulse monitor 4
When the abnormality detection signal is received from any one of the output monitor 4a, the output monitor 45a, the modulated wave monitor 46a, and the IQ level difference detection circuit 49a, the switching command signal is sent to the switch 48. At this time, the alarm / switch control unit 47 gives an alarm to the operator by emitting light from an LED or the like. The changeover switch 48 normally outputs a digital modulation wave from the transmission circuit 43a on the working line side, and when a changeover command signal is input,
Switch to the protection line. Each circuit on the protection line performs the same operation as that on the working line. When the connection is switched to the protection line, the digital modulation wave from the transmission circuit 43b of the protection line is output via the switch 48.

FIG. 11 is a diagram showing a configuration of a portion related to the IQ level difference detection circuit 49a. In the digital processing circuit 41 a, the input binary data is received by a serial / parallel converter (S / P) 411, distributed into three bits in parallel, and sent to a scrambler 412. Serial-parallel converter 4
The data output from the data 11 is data X for determining the phase of the I channel and data Y for determining the phase of the Q channel.
And data Z for determining the amplitudes of the I channel and the Q channel. The scrambler 412 randomizes the sequence of each data and sends the data X and the data Y to the differential logic conversion circuit 421.

The differential logic conversion circuit 421 adds the current data to the previous data and outputs the result as phase data.
The output data X and data Y are respectively D / A
The data is sent to the conversion circuit 422 and the D / A conversion circuit 423. D
The / A conversion circuit 422 converts the data X and the data Z into analog data and sends the analog data to the modulation circuit 425. On the other hand, D
/ A conversion circuit 423 is provided with data Y and inversion circuit 42
The data Z inverted in 4 is converted into analog data and sent to the modulation circuit 426.

The modulation circuit 425 digitally modulates the input data and outputs it as I-channel modulated data. Similarly, modulation circuit 426 digitally modulates the input data and outputs it as Q-channel modulated data. The hybrid (H) 427 combines the I-channel modulated data and the Q-channel modulated data and outputs a digital modulated wave.

If an error occurs in the scrambler 412 or the like and the value of the data Z is fixed at 1 or 0, the output of the D / A conversion circuit 422 and the D / A conversion circuit 42
An abnormality occurs in the level difference from the output of No. 3. The IQ level difference detection circuit 49a is a circuit that detects this level difference.

The outputs of the D / A conversion circuit 422 and the D / A conversion circuit 423 are input to the comparator 491 via the diodes D1 and D2, respectively, where the difference between the output levels is compared. The signal is converted into an analog signal by the circuit 492, and when an abnormality occurs in the difference between the output levels, the analog signal is output as an abnormality detection signal.

Next, a sixth embodiment of the present invention will be described. FIG. 12 is a diagram showing the configuration of the sixth embodiment of the present invention. Here, the configuration of a transmitting and receiving station in which a transmitting line and a receiving line are provided with a working line and a protection line, respectively, will be described. On the transmitting device side of the transmitting and receiving station of the present embodiment, a changeover switch 61 is provided at the output of the digital modulation circuit 51a of the working line and the digital modulation circuit 51b of the protection line, so that either one of the two is selected and output. It has become. On the other hand, each digital modulation circuit 51a,
The output of 51b is sent to a changeover switch 53 via transmission circuits 52a and 52b, respectively.

The changeover switch 53 selects the output of the transmission circuit 52 a when the working line is used, and sends it to the duplexer 54. The duplexer 54 outputs the digital modulated wave from the changeover switch 53 to the receiving station side, receives the digital modulated wave from another transmitting station, and sends it to the hybrid 55.

The output of the changeover switch 61 is sent to the changeover switch 62. The changeover switch 62 includes the changeover switch 6
1 is switched to either the changeover switch 63 or the changeover switch 64 and sent. The changeover switch 63 sends either the output of the changeover switch 62 or the output of the receiving circuit 56b to the digital demodulation circuit 57b of the protection line. The changeover switch 64 selects either the output of the changeover switch 62 or the output of the working receiving circuit 56a and sends it to the digital demodulation circuit 57a. The changeover switch 65 selects one of the outputs of the digital demodulation circuit 57a and the digital demodulation circuit 57b and sends it to the digital processing circuit (not shown). These changeover switches 53, 61 to 64,
65 is driven by a command from a monitoring and control device (not shown) in the station.

With such a configuration, in the transmitting / receiving station of this embodiment, for example, assuming that both the modulation circuit side and the demodulation circuit side use the working line, the changeover switch 61 switches the output of the digital modulation circuit 51a. Send to switch 62. The changeover switch 62 includes the changeover switch 6
The output from 1 is sent to the changeover switch 63. Then, the changeover switch 63 sends this to the digital demodulation circuit 57b.

As described above, the output of the used line on the output device side is connected to the unused line on the receiving device side, and the digitally modulated wave is received in its own station.
An abnormality in the spectrum of the currently output digital modulated wave can be detected in the own station.

Next, a seventh embodiment of the present invention will be described.
FIG. 13 is a diagram showing the configuration of the seventh embodiment of the present invention.
In the present embodiment, the modulation wave monitor 74 is provided immediately after the digital modulation circuit 71, not on the output side of the transmission circuit 72. The output of the transmission circuit 72 is sent to an output monitor 73 and a modulated wave monitor 74. On the output monitor 73 side, the digital modulation wave is detected and smoothed by the detection / smoothing circuit 73a, and the level is detected by the level detection circuit 73b to detect an abnormal transmission output level. On the other hand, the gain control circuit 73c sends a gain control signal corresponding to the output value of the detection / smoothing circuit 73a to the transmission circuit 72. This gain control signal is also input to the comparator 74c of the modulated wave monitor 74. The transmission circuit 72 having received the gain control signal performs control so that the output level is maintained at a constant value.

In the modulated wave monitor 74, the output of the transmission circuit 72 is passed through a band-pass filter (BPF) 74a, detected and smoothed by a detection / smoothing circuit 74b, and input to a comparator 74c. The comparator 74c compares the output value of the gain control circuit 73c with the output value of the detection / smoothing circuit 74b, and sends the comparison value to the level detection circuit 74d. The level detection circuit 74d determines the comparison value by the same method as that of the level detection circuit 23 shown in FIG. 3, and detects a spectrum abnormality.

[0069]

As described above, according to the present invention, the abnormalities of the waveform of the frequency spectrum of the digital modulation wave are detected by the modulation wave monitor, and the alarm processing is performed when the abnormalities of the waveform are detected. It is possible to easily detect an abnormality in the data at the preceding stage of the differential logic conversion on the transmission device side.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a block diagram illustrating a schematic configuration of a transmission device according to a first example of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a modulated wave monitor.

FIG. 4 is a diagram illustrating an example of a configuration of a bandpass filter.

FIG. 5 is a diagram illustrating a spectrum characteristic of a digital modulation wave that has passed through a band-pass filter.

FIG. 6 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a third exemplary embodiment of the present invention.

FIG. 8 is a diagram showing an internal configuration of a digital processing circuit and a digital modulation circuit.

FIG. 9 is a diagram showing a configuration of a fourth exemplary embodiment of the present invention.

FIG. 10 is a diagram showing a configuration of a fifth exemplary embodiment of the present invention.

FIG. 11 is a diagram showing a configuration of a portion related to an IQ level difference detection circuit.

FIG. 12 is a diagram showing a configuration of a sixth example of the present invention.

FIG. 13 is a diagram showing a configuration of a seventh exemplary embodiment of the present invention.

FIG. 14 is a block diagram illustrating a schematic configuration of a conventional transmission device.

15 is a diagram showing a specific configuration of a portion related to digital modulation processing in the configuration of FIG. 14;

16A and 16B are diagrams showing the characteristic shape of the spectrum of the output unit, where FIG. 16A is a characteristic diagram at the time of failure in the N1 stage, and FIG.
And (C) are characteristic diagrams at the time of failure in the N2 stage, and (D)
(E) and (E) are characteristic diagrams at the time of failure in the N3 stage.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Digital modulation circuit 2 Modulation wave monitor 3 Alarm processing means 4 Transmission circuit 21 Band pass filter 22 Detection / smoothing circuit 23 Level detection circuit

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-55-163936 (JP, A) JP-A-5-199269 (JP, A) JP-A-59-6652 (JP, A) JP-A-59-6652 77749 (JP, A) JP-A-3-239041 (JP, A) JP-A-1-317010 (JP, A) JP-A-61-131152 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 27/00-27/38 H04B 1/04-7/26

Claims (9)

(57) [Claims] 1. A digital modulation circuit (1) for performing a differential logic conversion of input data to convert the input data into a digital modulation wave in a method of monitoring a digital modulation wave generated by a wireless transmission device. A modulated wave monitor (2) for detecting abnormalities in the waveform of the frequency spectrum, an alarm processing means (3) for performing alarm processing when the abnormalities in the waveform are detected, and a transmission for outputting the digitally modulated waves to a receiving side. The circuit (4) and the large amplitude for the I channel and the Q channel from the input data.
Serial / parallel conversion to generate width data and small amplitude data
Means for inputting to the differential logic conversion means for performing the differential logic conversion.
Force data of the large amplitude data and the small amplitude data
A changeover switch for selecting and switching to one, and alternately switching between the large amplitude data and the small amplitude data.
Path control means for controlling the changeover switch to change
And a method for monitoring a digitally modulated wave, comprising:
formula. 2. A digital conversion device generated by a wireless transmission device.
In the harmonic monitoring method, input data is subjected to differential logic conversion to digital conversion.
A digital modulation circuit (1) for converting to a harmonic, and a difference between the waveform of the frequency spectrum of the digitally modulated wave.
A modulated wave monitor (2) for detecting normality, and an alarm for performing alarm processing when abnormalities of the waveform are detected.
And a transmission circuit for outputting the digital modulated wave to a receiving side
(4) , provided in the subsequent stage of the differential logic conversion means of the 8PSK transmission device
Output level of I channel data and Q channel
And compare the output level of the
A scrambler provided before the differential logic conversion means.
And a IQ level difference detecting means for detecting an abnormality in the digital modulated wave.
formula. 3. A digital conversion device generated by a wireless transmission device.
In the harmonic monitoring method, input data is subjected to differential logic conversion to digital conversion.
A digital modulation circuit (1) for converting to a harmonic, and an alarm for performing an alarm process when an abnormality is detected in the waveform.
And a transmission circuit for outputting the digital modulated wave to a receiving side
(4) detecting the output level of the transmission circuit and responding to the detected value
Output monitor for feeding back the gain control signal to the transmitting circuit side.
And an intermediate frequency component of the output level.
Control signal level, and according to the comparison value,
Detects abnormalities in the frequency spectrum of digitally modulated waves
And a modulated wave monitor (2) for monitoring a digitally modulated wave.
formula. 4. The modulated wave monitor (2) includes:
That passes only the predetermined frequency band in the middle of the
Through the bandpass filter and the bandpass filter.
Detection and smoothing circuit for detecting and smoothing digital modulated waves
And the level of the detected and smoothed digital modulated wave.
Level detecting means for detecting an abnormality based on the bell value.
The disk according to claim 1, 2 or 3, wherein
Digital modulation wave monitoring method. 5. The apparatus according to claim 1 , wherein said level detecting means is configured to output said predetermined frequency.
The level in the band is higher than the normal level.
Is higher or lower than the lower limit.
5. The apparatus according to claim 4, wherein
The digital modulation wave monitoring method described above. 6. The predetermined frequency band is equal to a Nyquist width.
The contract is characterized in that it is set to be narrower
A method for monitoring a digitally modulated wave according to claim 4. 7. An alarm processing means (3), comprising :
A contract display configured to perform
A method for monitoring a digitally modulated wave according to claim 1, 2, or 3.
formula. 8. The alarm processing means (3) includes:
When a shape error is detected, switching between the working line and the protection line
The switch command signal to the changeover switch
4. The method according to claim 1, wherein
The monitor method of the digital modulation wave described in the above. 9. A switching means provided in one transmission / reception station for selecting an output of a digital modulation circuit currently used and connecting the output to a digital demodulation circuit not currently used. Claims 1 and 2
Or a method of monitoring a digitally modulated wave according to 3 .