JPH06242172A - Detecting method for disconnection of speaker circuit - Google Patents

Abstract

PURPOSE:To simply detect the disconnection of a speaker circuit by dispensing with a tone back circuit and moreover an actual signal blowing in a detecting method for disconnection of a speaker circuit which is used for many emergency guidance broadcasting processes including a dam discharging alarm. CONSTITUTION:Since, when an inspection switch is closed, electric current flows from an output transformer 1 to a voice coil 4 and further to the output transformer 1, a photocoupler 6 turns into an on-state. If any disconnection occurs in a circuit, the electric current does not flow as above mentioned, the photocoupler 6 therefore turns into an off-state, and the disconnection can be judged.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker and its circuit which are exposed to the danger of disconnection under a severe environment such as rain, wind and snow, especially in a loudspeaker system to be installed outdoors. It is used to detect a disconnection state.

2. Description of the Related Art Conventionally, a method of detecting a disconnection of a speaker line is a tone back detection by an actual signal sounding. Therefore, a tone-back line is required in addition to the speaker line, and the level detection circuit is complicated. Further, due to the actual sound of the signal, the inspection process can be practically performed only once or twice a day, which is not suitable for a 24-hour system.

[0002]

SUMMARY OF THE INVENTION According to the present invention, a disconnection of a speaker line can be easily detected without requiring a tone-back line, and a disconnection can be detected without requiring actual signal sounding. This enables a speaker disconnection detection method that enables 24-hour monitoring.

[Means for Solving the Problems]

Reference number = K-011-92T
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---------- First, the structure of the present invention will be described with reference to the drawings. In FIG. 1, 1 is an output transformer, 2 is a capacitor for connecting the secondary side of the output transformer with alternating current,
3 is a speaker, 4 is a voice coil in the speaker, 5 is an inspection switch, and 6 is a photocoupler for outputting a speaker disconnection detection signal.

[0003]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a part of a secondary side of an output transformer 1 is cut off and connected with a capacitor 2. By connecting with the capacitor of 2, the voltage of the actual signal blowing on the output transformer of 1 does not cause any trouble because it is an alternating current. When a DC voltage is applied to both ends of this 2 capacitor, a DC current can be passed through the speaker line via the 4 voice coil of the 3 speaker. In the present invention,
A method of receiving this direct current by the photo coupler 6 and detecting disconnection of the line including the speaker 3 is adopted.

When the check switch 5 is closed, a current flows from the output transformer 1 to the voice coil 4 and further to the output transformer 1 so that the photocoupler 6 is turned on. If the wire breaks somewhere, the current does not flow as described above, so that it can be determined that the photocoupler 6 is in the off state and the wire is broken.

[0005]

【The invention's effect】

1) A tone-back line is not required separately from the speaker line for detecting disconnection. 2) Since the disconnection is not detected by the actual signal, no extra sound is emitted from the speaker during inspection. 3) To prevent unnecessary noise from the speaker during inspection, 2
4-hour monitoring reference number = K-011-92T
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-------------- 4) It can be realized at a low cost because it can be realized with a simple configuration.

[0006]

[Brief description of drawings]

FIG. 1 is a diagram for explaining the structure and operation of the present invention.

[Explanation of symbols]

 1 Output transformer 2 Capacitor 3 Speaker 4 Voice coil 5 Inspection switch 6 Photo coupler

Claims (1)

[Claims] 1. In many emergency broadcasts, such as dam discharge warnings, etc., a direct current is applied to the speaker line used and the current or voltage is monitored to detect disconnection of the speaker line. Method for detecting disconnection of speaker line that enables wireless communication. [0001]