JPS62294345A - Transmission alarm detection circuit in time division multiplex communication equipment - Google Patents

Abstract

PURPOSE:To quickly send a transmission output interruption alarm even if the signal input line of a transmission output control signal is opened by providing a transmission output monitor circuit, a 1st discrimination circuit, a signal interruption detection circuit, a 2nd discrimination circuit and an OR circuit. CONSTITUTION:If the input signal line for the transmission output control signal is opened, a line open detector 18 is operated, interrupts the output from a selector 1A and gives the information to the 2nd discrimination circuit 4. The 2nd discrimination circuit 4 outputs a high level momentarily based on the information, a transmission output interruption alarm is outputted from an OR circuit 5 and the maintenance personnel recognizes it instantly. In applying the open wire detection for the signal line by the 1st discrimination circuit 3, to the discrimination it takes for some time and it is discriminated to use the information representing the presence of an input signal to relieve the defect of a conventional circuit.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a transmission alarm detection circuit in a TDMA (time division multiplex) communication device, and particularly relates to a transmission alarm detection circuit that also serves as a signal disconnection detection circuit. This invention relates to an improvement in technology for detecting a transmission output cutoff alarm using control signal information.

[Prior Art] In the conventional TI) MA wireless communication system, the subscriber side transmits only during the allotted time, so the transmission output is adjusted by sampling and holding the detected voltage using pulses generated from the transmission output control signal. It monitors the detected voltage and sends out a warning that the transmission output has been cut off.

[Problems to be Solved] In the conventional alarm detection method described above, when the input line of the transmission output control signal is disconnected and disconnected, the transmission output monitor maintains a hold state because no sample pulse comes. Therefore, due to leakage through the hold capacitor, the hold voltage gradually decreases, and when the determination point is exceeded, an alarm is sent out indicating that the transmission output has been cut off.It takes time to make the determination, and there are variations depending on the element. It had drawbacks.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned conventional problems and provide a transmission alarm detection circuit for a time division multiplex communication device that can promptly send out a transmission output disconnection alarm.

[Means for solving the problem] In a time division multiplex communication device that stops transmission when a transmission output control signal that controls the timing of a transmission burst signal is disconnected, a transmission output monitor circuit that monitors a transmission output control signal; a first determination circuit that determines transmission output disconnection based on a monitor output; a signal disconnection detection circuit that detects disconnection of the input signal line for the transmission output control signal; and a signal disconnection detection circuit that detects transmission output disconnection based on the output of the signal disconnection detection circuit. a second determination circuit for determining; and a second determination circuit for determining the first. A transmission alarm detection circuit is configured by providing a logical sum circuit which takes the logical sum of the output of the second determination circuit and generates a transmission alarm.

[Example] Next, an example of the present invention will be described with reference to the drawings.

The drawing is a block diagram of an example device.

In the figure, 1 is a signal disconnection detection circuit, and a selector IA
and a disconnection detector IB. Said selector I
A and disconnection detector IB are configured to receive a transmission output control signal for controlling the timing of the transmission burst signal from a circuit termination device (not shown) via a transmission line. The disconnection detector IB detects a disconnection in the transmission output control signal line and outputs a signal indicating that the transmission output is disconnected. The selector IA normally selects and outputs the transmission output control signal side, and the disconnection detector IA selects and outputs the transmission output control signal side.
Only when disconnection is detected at B, a signal is output to disconnect the transmission output.

2 is a transmission output monitor circuit, which is composed of a pulse generator 2A and a sample and hold circuit 2B. The pulse generator 2A generates pulses from the transmission output control signal inputted through the selector IA, and the sample and hold circuit 2B samples and holds the detected voltage based on this pulse, and monitors the transmission output. It is supposed to be done.

3 is a first determination circuit which inputs the output of the transmission output monitor circuit 2, determines this monitor output, and outputs rHIGHJ if the transmission output is off, and rLO otherwise.
Output WJ.

4 is a second determination circuit which inputs the output of the disconnection detector IB of the signal disconnection detection circuit 1, and outputs rHIGHJ when it determines that the signal line is disconnected; otherwise, it outputs "Lo".
W" is output.

5 is an OR circuit, and the first. Second judgment circuit 3.
When two people output the output of 4 and the logical sum condition is satisfied, that is,
A transmission output disconnection alarm is output when at least one of the outputs is rHIGHJ.

According to the transmission alarm detection circuit configured as described above, normally the transmission control signal is monitored by the transmission output monitor circuit 2, and by determining the detected voltage which is the monitor output, the first alarm detection circuit is activated when the transmission output is cut off. rHIGHJ from judgment circuit 3
is output. As a result, a transmission output disconnection alarm is output from the OR circuit 5, and the subscriber side can perform time division multiplex communication in the allocated time.

On the other hand, when the input signal line for the transmission output control signal is disconnected, the disconnection detector IB operates and sets the output from the 1 selector IA as the transmission output disconnection, and this information is sent to the second determination circuit 4.
input. The second determination circuit 4 instantaneously outputs rHIGHJ based on this information, and the OR circuit 5 outputs a transmission output disconnection alarm, allowing the maintenance person to immediately recognize this.

Note that if the first determination circuit 3 also performs the disconnection detection when the signal line is disconnected in this way, as described above, the determination takes time and a transmission disconnection alarm cannot be issued promptly. By determining this based on information on the presence or absence of an input signal as in this embodiment, the conventional drawbacks can be overcome.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible within the scope of the invention.

[Effects of the Invention] As described above, according to the present invention, even if the signal input line for the transmission output control signal is disconnected, a transmission output disconnection alarm can be promptly sent.

[Brief explanation of drawings]

The drawing is a block diagram of one embodiment of the present invention. l: Signal disconnection detection circuit 2: Transmission output monitor circuit 3: First judgment circuit 4: Second judgment circuit 5: OR circuit

Claims (1)

[Claims] A time division multiplex communication device that stops transmission when the transmission output control signal that controls the timing of the transmission burst signal is disconnected includes a transmission output monitor circuit that monitors the transmission output control signal, and a transmission output disconnection circuit that monitors the transmission output control signal based on this monitor output. a signal disconnection detection circuit that detects disconnection of the input signal line for the transmission output control signal; and a second determination circuit that determines transmission output disconnection based on the output of the signal disconnection detection circuit. A transmission alarm detection circuit in a time division multiplex communication device, characterized in that the transmission alarm detection circuit is provided with: and an OR circuit which takes the logical sum of the outputs of the first and second determination circuits and generates a transmission alarm.