JPH02131065A - Data transmission system - Google Patents

Abstract

PURPOSE:To quickly cope with the occurrence of a network fault by sending a modulation signal at a voice frequency band with a tone signal assigned to an intermediate frequency band between a band assigned with a data and a band assigned with monitoring information to a reception section. CONSTITUTION:A modulation signal is generated, in which monitoring information is assigned to a lower frequency band in a voice frequency band and a data to be sent is assigned to a high frequency band not overlapped with the low frequency band. That is, the output of a tone signal generator 14 in a transmission section is given to a signal generator control switch 15 and a band pass filter 16 to generate a tone modulation signal (c) and a main channel modulation signal (a) and a diagnostic channel modulation signal (b) are added by adders 11, 17. Then the result is given to a transmission output signal attenuator 12 and a low pass filter 13 to generate a transmission output signal (d). A reception input signal (e) is given to a tone signal detection band pass filter 23 in the reception section and a tone signal detector 24 detects a tone demodulation signal (h).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is applied to a data transmission system in a multipoint line. In particular, it relates to a data transmission method using a diagnostic channel dedicated to network monitoring.

〔overview〕

The present invention provides control signals by independently allocating tone signals to a band intermediate between a band to which data is allocated and a band to which monitoring information is allocated, in a method of allocating and transmitting data and monitoring information to an audio frequency band. This shortens the transmission time for information such as information and status signals, and allows for rapid response to the occurrence of failures.

[Conventional technology]

When monitoring a network, a channel called a diagnostic channel is used to transmit control signals and status signals, regardless of whether it is a multipoint line or a point-to-point line. This diagnostic channel uses a different frequency band within the audio frequency band, independent of the main channel for data communication, and so as not to interfere with each other.

The configuration of a conventional example is shown in FIG.

[Problem that the invention seeks to solve]

In such a conventional example, since the diagnostic channel has a narrow band, the data communication speed of the channel is slow, and it takes time to transmit control signals and status signals. Furthermore, in the case of a multipoint line, control signals and status signals are transmitted by a master station by sequentially polling a plurality of slave stations, so the more slave stations there are, the slower the information transmission. That is,
A delay of seconds occurred in transmitting urgent information from a slave station (for example, an automatic equalizer divergence or an emergency situation on the user's side).

SUMMARY OF THE INVENTION The present invention aims to eliminate such drawbacks and to provide a data transmission system that allows emergency information to be collected without delay.

[Means for solving problems]

The present invention provides a transmitting section having a first means for generating a modulated signal in which monitoring information is assigned to a low frequency band of the audio frequency band and data to be transmitted is assigned to a high frequency band that does not overlap with the low frequency band. In a data transmission system including a receiving section connected to the transmitting section via a multipoint line, the transmitting section transmits a tone signal in an intermediate frequency band that does not overlap with the low frequency band and the high frequency band. The receiving section is characterized in that it has a second means for allocating and superimposing the received modulated signal on the modulated signal, and the receiving section has a third means for demodulating the incoming modulated signal and extracting a tone signal from the demodulated signal.

[Effect]

When the transmitting side transmits a modulated signal in the audio frequency band with a tone signal assigned to a frequency band intermediate between the band to which data is assigned and the band to which monitoring information is assigned, the receiving side uses a bandpass filter to modulate the tone signal. The frequency band is filtered and a tone signal is detected based on the filtered signal.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of this embodiment.

FIG. 2 shows the spectrum of each channel signal and tone signal.

As shown in FIG. 1, this embodiment generates a modulated signal in which monitoring information is assigned to a low frequency band of the audio frequency band and data to be transmitted is assigned to a high frequency band that does not overlap with this low frequency band. an adder 11, a transmission output signal attenuator 12, and a low-pass filter 13, which are the first means for
and a receiving section connected to the transmitting section via a multipoint line, and the transmitting section further transmits a signal to an intermediate frequency band that does not overlap with the low frequency band and the high frequency band. It has a bandpass filter 16 and an adder 17, which are second means for allocating a tone signal and superimposing it on the modulated signal, and the receiving section demodulates the incoming modulated signal and extracts the tone signal from this demodulated signal. It has a tone signal detection bandpass filter 23 and a tone signal detector 24, which are third means for detecting tone signals.

Next, the operation of this embodiment will be explained.

In the transmitting section, the output of the tone signal generator 14 is passed through the tone signal generator control switch 15 and the bandpass filter 16 to generate a tone modulation signal C, which is then added to the main channel modulation signal a and the diagnostic channel modulation signal S. vessels 11 and 1
7 to generate a transmission output signal d through a transmission output signal attenuator 12 and a low-pass filter 13. In the receiving section,
The received human input signal e is passed through a tone signal detection bandpass filter 23, and a tone signal detector 24 detects a tone demodulated signal.

〔Effect of the invention〕

As explained above, the present invention has the advantage that the transmission time of control signals, status signals, etc. in a multipoint line is shortened from seconds to milliseconds, and it is possible to quickly respond to the occurrence of network failures. There is.

Further, even if the number of multi-point slave stations increases, there is an effect that the transmission time is not affected.

Furthermore, since the edge band of the voice band is not used, reliable transmission can be achieved even in areas where line loss is large.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram showing the configuration of an embodiment of the present invention. Figure 2 shows the spectrum of the main channel diagnostic channel and tone signal. FIG. 3 is a block configuration diagram showing the configuration of a conventional example. 11.17...Adder, 12...Transmission output signal attenuator, 13...Low pass filter, 14...Tone signal generator, 15...Tone signal generator control switch, 16
... Bandpass filter, 21... Bandpass filter for main channel, 22... Bandpass filter for diagnostic channel, 23...
- Bandpass filter for tone signal detection, 24...Tone signal detector, a...Main channel modulation signal, b...Diagnostic channel modulation signal, C...Tone modulation signal, d...
- Transmission output signal, e... Received human input signal, f... Main channel demodulated signal, g... Diagnostic channel demodulated signal,
h...Tone demodulation signal.

Claims (1)

[Claims] 1. A first means for generating a modulated signal in which monitoring information is allocated to a low frequency band of the audio frequency band and data to be transmitted is allocated to a high frequency band that does not overlap with this low frequency band. In a data transmission method comprising a transmitting section having a transmission section and a receiving section connected to the transmitting section via a multipoint line, the transmitting section transmits data at an intermediate frequency that does not overlap with the low frequency band and the high frequency band. The receiving section has a second means for allocating a tone signal to a band and superimposes it on the modulated signal, and the receiving section has a third means for demodulating the incoming modulated signal and extracting the tone signal from the demodulated signal. Characteristic data transmission method.