JPS6267470A - Misconnection detector for electronic apparatus - Google Patents

Abstract

PURPOSE:To prevent misconnection, by permitting one of two electronic appliances (e.g., TV set and VTR) to judge on the correct connection therebetween from the signal level at an output terminal and the level of an input impedance of an input terminal of the other. CONSTITUTION:A disconnection detecting circuit 11 has input terminals A-D. A high-pass filter 12 is connected to the terminal A with a cutoff frequency allowing the cutting of a voice band and a signal level sensor 14 comprising a detection circuit and a comparator is connected to the terminal B through a capacitor C1 while an AC oscillator 15 is also done thereto through a resis tance R1. A signal level sensor 14 is connected to the terminal C and the termi nal D is arranged the same as the terminal B to examine an input impedance. With such an arrangement, the connection is determined to be normal only when a video output is connected to the terminal A, a video input to the termi nal B, a voice output to the terminal C and a voice input to the terminal D and otherwise, all are determined to be abnormal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a connection error detection device for electronic equipment such as a video tape recorder and a television receiver that can exchange signals with each other.

<Overview> The present invention provides a connection determination signal to one of two electronic devices by determining whether the connection is correct or incorrect based on the signal level of the output signal obtained from the output terminal of the other electronic device and the input impedance level of the input terminal. This is intended to prevent errors in connection between slave devices in both chambers.

<Prior Art> Looking at video tape recorders, television receivers, etc. currently on the market, as shown in FIG. 4, the video tape recorder VTR has a video signal output terminal 1. Video signal input terminal 2. The other party's television receiver TV is equipped with an audio signal output terminal 3 and an audio signal input terminal 4.
is equipped with a video signal input terminal I', a video signal output terminal 2', an audio signal input terminal 3' and an audio signal output terminal 4',
Each terminal 1-1', 2-2', 3 between delimiter devices
By connecting between -3' and 4-4', a normal connection state can be established.

<Problem that the invention seeks to solve> However, all of the above individuals and output terminals are the same.

Because they are connected at the same size, people are used to making connections by mistake, and no measures have been taken to prevent incorrect connections. It will also happen.

<Means for Solving the Problems> The present invention (-1) was invented in view of the drawbacks of the above-mentioned conventional devices, and in a device for detecting connection errors between first and second electronic devices, the above-mentioned a level detecting means for detecting the level of an output signal obtained from the output terminal of the second electronic device, and outputting a signal of a predetermined logical value when the level is equal to or higher than a predetermined value; Level detection means detects the input impedance of the input terminal of the second electronic device and outputs a signal with a predetermined logical value when it is a predetermined value, and connection is determined based on the logic value of both of the above/bell detection means. An electronic device is provided with a determination signal output means for outputting a signal, and an error detection device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. In this embodiment, a video tape recorder and a television receiver are used as the electronic devices, and the same parts as in the prior art are denoted by the same reference numerals.

Figure 1 shows the back of the video tape recorder VTR and television receiver TV.
The R side has a video signal output terminal as before! , video signal input terminal 2. Audio signal output terminal 3 and audio signal input terminal 4
, the video signal input terminal 1 is on the TV side of the television receiver.
', an audio signal input terminal 2', an audio signal input terminal 3', and an audio signal output terminal 4'.

FIG. 2 shows a block electrical circuit diagram of a connection error detection device according to the present invention provided on the TV side of the television receiver, in which 5 is a changeover switch circuit C consisting of an analog switch, etc. The movable contact a is connected to the video signal input terminal 1', the video signal output terminal 2', and the audio signal input terminal 3'.
, and the audio signal output terminal 4' (while connecting the movable contact a to the main circuit 10: the fixed contact connected to this, and the fixed contact C connected to the connection error detection circuit 1). It has a configuration and is equipped with 9 to 9 increments.

The changeover switch circuit 5 detects a connection error in the movable contact a of each switch 6 to 9 as shown in the figure until each terminal 1' to 4' of the video tape recorder VTR is properly connected. The fixed contact C connected to the circuit 11 is turned on, but when a no-error signal is output from the close reading error detection circuit 11, the movable contact A is turned on to the main circuit 1o. The main body circuit 10 and the video tape recorder VTR can transmit and receive video and audio signals.

Here, the connection error detection circuit 11 will be explained with reference to FIG.

Such a circuit 11 connects each of the fixed contacts C of the above-mentioned switches 9 to 9.
There is an input terminal from A to corresponding to
(In this case, bypass filters 12 with a cant-off frequency (for example, about 100 KHz) that can cut the audio band are connected, and when a video composite signal is input to input terminal A, such a signal... A signal level sensor 13) consisting of a detector, a time constant circuit, a comparator, etc. is supplied through the filter I2, and when the video composite signal is at a predetermined level or higher, the signal level sensor 13 outputs a level 111''. It consists of

Further, a signal level sensor 14 consisting of a detection circuit and a comparator is connected to the input terminal B via a capacitor C1, and an AC oscillator 15 is connected via a resistor R1, and the input terminal B is connected to the switch 7 and the video signal output terminal. The input impedance at the video signal input terminal 2 of the video tape recorder VTR (for example, 75
Ω). In other words, the level is lower than the reference level set in the comparator of the signal level sensor 14id-t according to the input impedance (the AC component from the AC oscillator 15 that has changed depending on the input impedance is converted into a DC component by the detection circuit in the signal level sensor 14). When the voltage level (voltage level changed to Since the input impedance is large, for example, 10 to 50Ω, the input level to the signal level sensor 14 is higher than the above reference level, so the signal level sensor 14 outputs a 90″ level. Also, the input terminal C
17tLij is connected to the signal level sensor I6, and the sensor 16il''i' is configured to set the output to the level '1'' if there is a video or audio signal from the video tape recorder VTR. Capacitor C
A signal level sensor 17 consisting of a comparator on the detection circuit is connected through the detector circuit 2, and an AC oscillator I5 is connected through the resistor R2, and the input terminal is connected through the switch 9 and the audio signal output terminal 4'. The input impedance (for example, 10 to 50 ohms) at the audio signal input terminal 4 of the video tape recorder VTR is checked. In other words, the input level corresponding to the input impedance is lower than the reference level set in the converter of the signal level sensor 17 (the AC component from the AC oscillator !5 changed depending on the input impedance is detected by the detection circuit in the signal level sensor 17). When the voltage level (voltage level changed to DC component) is large, a logical value signal is output to the output.If the audio signal output terminal 4' is connected to the video signal input terminal 2
When connected to the signal level sensor 17, the input impedance of the input terminal 2 is as small as 75Ω, for example.
Since the input level to the signal level sensor +7 is lower than the reference level, the signal level sensor +7 outputs the "0" level.

18 is an AND circuit that outputs "output enabled" when the outputs of all the signal level sensors +3, 14, 16 and 17 are at the "town" level, and I9 is an AND circuit that outputs an output when the output of the "11" level is obtained from the AND circuit 18. This is an R-S flip-flop circuit that receives the signal at the set terminal S and enters a set state, setting the output terminal Q to the Jl level, that is, outputting a connection determination signal.The AND circuit 18 and the R-S flip-flop circuit 1
Reference numeral 9 constitutes a judgment signal output means in the present invention.

Then, the connection judgment signal which became ゝゝ1'' is displayed on the display 2.
0 to drive the display 20 to display that there is no connection error, while the changeover switch circuit 5
The present invention is constructed in a manner similar to that of a confinement, and is used to connect a video tape recorder VTR and a television receiver TV to signal signals. When connecting so that transmission and reception are possible, the movable contacts a of each switch 6 to 9 of the changeover switch circuit 5 are turned on to the fixed contact C, and the video signal output terminal! and video signal input terminal 1', video signal input terminal 2 and video signal output terminal 2', audio signal output terminal 3 and audio signal output terminal 3', and audio signal input terminal 4 and audio signal output terminal 4', respectively. If the video tape recorder VTR is driven while connecting with a connector without connecting, all signal level sensors in the connection error detection circuit 11 +3.14.1
6 and 17u 11 + Tr level output, and based on this, the output of the AND circuit 18 is closed to 91", and from the output terminal Q of the R-S flip-flow knob 19, "■" indicating that there is no conjunction shi is output. Outputs the level connection judgment signal.

This determination signal is then supplied to the display 20, while
The signal is supplied to the changeover switch circuit 5 to switch the movable contacts a of each switch 6 to 9 from the fixed contact C to b.

As a result, the video tape recorder VTR and the television receiver TV can exchange signals between them.

By the way, when connecting each output terminal with a connector as described above, if the connection is incorrect, for example, the audio signal output terminal 3 of a video tape recorder VTR may be connected to the video signal input terminal 1' of a television receiver. Then, the input terminal of the connection error detection circuit 11 is connected to the video tape recorder VT.
An audio signal is input as R is driven, but since this audio signal is cut by the no-pass filter 12, the signal level sensor 13 outputs a level of 10''.

Therefore, the AND circuit 18 does not output +1', but R-
50' from S flip-flop 19 indicating a connection error.
A level determination signal is output.

Furthermore, even if the video and audio signal output terminals 2' and 4' of the television receiver TV are mistakenly connected to the audio and video signal input terminals 2.4 of the video tape recorder VTR, the signal level sensor 14.17 will not output any output. 0” level, R-
A 10'' level connection determination signal is output from the S flip-flop 19, and each switch of the changeover switch circuit 5 keeps its movable contact a connected to its fixed contact C.

<Effects> Since the present invention is constructed in a narrow manner, input/output terminals between electronic devices that exchange signals with each other can be connected without error.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the main part of the back of an electronic device equipped with a connection error detection device according to the present invention, and FIG. 2 is a block electric circuit diagram showing an embodiment of the connection error detection device according to the present invention. FIG. 3 is a specific circuit diagram of a connection error detection circuit in the above device, and FIG. 4 is a diagram showing the front side of a conventional electronic device. 11. Connection error detection circuit, +3.14.16 and 17:
Signal level sensor, 18)” Do road, 19
:R-S flip/70 tube circuit. Agent Patent attorney Aihiko Fuku (and 2 others) Figure 1 $2 g No. 3511 No. 4 gt

Claims (1)

[Claims] 1. A device for detecting a connection error between a first and a second electronic device, wherein a signal of an output signal obtained from an output terminal of the second electronic device is provided on the side of the first electronic device. Level detecting means detects the level and outputs a signal of a predetermined logical value when the level is equal to or higher than a predetermined value, and detects the input impedance of the input terminal of the second electronic device and detects the input impedance of the input terminal of the second electronic device, and detects the input impedance of the input terminal of the second electronic device. A connection error detection device for an electronic device, comprising: level detection means for outputting a signal with a predetermined logical value; and determination signal output means for outputting a connection determination signal based on the logical values of both of the level detection means.