JPH0419783A - Warning circuit for display device abnormal frequency - Google Patents

Abstract

PURPOSE:To prevent a display device from becoming faulty by generating an alarm sound when a synchronizing signal which is not in an operation range is inputted from a host computer or other relative equipments while the display device is connected to the host computer or other relative equipments and put in operation. CONSTITUTION:The output signal of an F/V converter 2 which inputs a synchronizing signal is inputted to the circuit composed of one or plural monostable multivibrators 9, 12, and 15 to obtain circuit constitution which indicates that the synchronizing signal which is not within the operating frequency range is inputted to the display device visually and with the sound by operating an alarm sound output circuit 20 with the obtained output signal. Consequently, the display device is prevented from becoming faulty by generating the alarm sound indicating that the synchronizing signal outside the operation range is inputted during the operation of the display device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates particularly to a display device used with a host computer and related equipment that supply horizontal synchronization signals to the display device, The present invention relates to a display device abnormal frequency warning circuit for notifying users or related parties that a synchronization signal outside the operating frequency range is being input based on the state of the synchronization signal.

[Prior Art] In conventional display devices, when a horizontal synchronization signal outside the operating frequency range is input, the displayed image becomes distorted or disturbed, making it possible to confirm that the synchronization signal is outside the operating frequency range. . However, with this, it is only visually apparent that a synchronization signal outside the operating frequency range is being input to the display device. Additionally, during this time, the deflection circuit attempts to follow frequencies outside its operating range, increasing the load on the circuit and potentially causing it to malfunction. Therefore, if a visual check is not performed, such as not looking at the screen for some reason, such an abnormality cannot be confirmed.

[Problems to be Solved by the Invention] As described above, in the conventional technology, since there is no checking function other than visual, when a synchronization signal outside the operating layer wave number range is input to the display device, the deflection circuit has to follow that frequency. However, there were problems such as an increase in the load on the circuit, leading to breakdowns.

[Means for Solving the Problems] The present invention provides an output signal of an F/V converter (2) whose synchronization signal is manually generated by one or more mono-multi-by-brakes (9), (12), and (15). This circuit operates a warning sound output circuit using the obtained output signal as an input to the circuit, thereby notifying the display device visually as well as by sound that a synchronization signal outside the operating frequency range is being input to the display device.

[Effect 1] According to this, it is possible to prevent the display device from malfunctioning by making audible notification that a synchronization signal outside the operating range is being input while the display device is in operation.

[Example] In Fig. 1, the input terminal (1
) is connected to the operational amplifier (3) through the F/V converter (2).
) and the non-inverting input of the operational amplifier (4). Also, the inverting input of the operational amplifier (4) is connected to the resistor (6).
(5) to the power supply terminal (8), and the connection midpoint of the resistors (6) and (5) is connected to the non-inverting input of the operational amplifier (3). Further, the outputs of the operational amplifiers (3) and (4) are connected to the input of the AND circuit (7). Furthermore, the output of AND time i (7) is mono multi-by flake - (9),
(12) is connected to the six inputs. The mono multivibrator used here has B input and CLR input terminals set to HIGH.
In the H state and when the A input falls, the Q output generates a positive pulse of arbitrary width. Furthermore, the mono multi-by-break is reset at the falling edge of the CLR input terminal. Also, the output of the AND circuit (7) is the NOT circuit (22
), CLR of mono-multivibrator (9)
Connected to the input terminal. Also mono multi-by break
(9) B input, mono multi-bi break - (12) B input, CLR input terminal, mono multi-bi break - (
The B input and CLR input terminals of 15) are connected to the power supply terminal (9). Furthermore, resistor (11) and capacitor (10)
, and the resistor (14), capacitor (1, 3), resistor (17), and capacitor (16) determine the time constants of the mono multi-vibration breaks (9), (12'), and (15+), respectively. If the time constant of mono multivibrator (12) is tb, and the 8-temple constant of monomultibibreak (15) is tc, then monomultivibrator (9)
resistor (11) so that the time constant ta becomes tb+tc.
(14) (17) and capacitors (10) (13) (16
). Mono multi-vi break-(12)
The Q output of is connected to the 6 inputs of a mono multi-bi break (15). Furthermore, mono multi-by break-(9)
and the Q output of mono multi-by-break-(15) is AND
It is connected to the circuit (18). Furthermore, AND circuit (18)
The output of is passed through the resistor (19) to the transistor (2])
The emitter of the transistor (21) is grounded. Further, the collector of the transistor (21) is connected to the electric terminal (8) through the warning sound generating circuit (20). The warning sound generation circuit is composed of a buzzer and a driver, but it can also be composed of a voice synthesis circuit and a speaker.

Therefore, in this circuit, when the horizontal synchronizing signal as shown in Figure 2 A that was being supplied to the F/V converter (2) reaches a frequency outside the operating range, the output of the AND circuit (7) will become as shown in Figure 2 B. Changes from HIGH state to LOW state. And the LOW state is the mono multivibrator (
12), the mono-multi-by-break-(12
) is set and mono multi-bi break - Q of (12)
As shown in Figure C, the state is 11GF (tb seconds). At the falling edge of the pulse after tb seconds, the mono multivibrator (15) is set, and the Q of the monomultivibrator (15) is as shown in the same figure. Multi-by-break = (9
) is supplied to A of mono-multi-by-break - (9)
is set, and the Q of the mono-multivibrator (9) is in a HIGH state for ta seconds as shown in FIG. Furthermore, as shown in Figure F, the output of the AND circuit (18) is
It becomes H state. When it is supplied to the base of the transistor (21), the transistor (21) is turned on, and during that time, the alarm sound generation circuit sounds.

Also, a horizontal synchronizing signal within the operating range is supplied to the input terminal (1) again within tb seconds after the output of the AND circuit (7) becomes LOW, and the output of the AND circuit (7) becomes HIGH. When the condition is reached, the mono multi-by-break (9) is reset through the NOT circuit, and as a result, the output of the AND circuit (18) does not become HIGH, so the warning sound generation circuit does not operate.

In this way, the display device is audibly notified that a synchronization signal outside the operating range has been input from the host computer or related equipment, and damage to the display device due to input of a synchronization signal outside the operating range is prevented. According to this circuit, it is possible to control the ringing time by controlling the time constant of the mono multivibrator, so by setting an effective ringing time, it is possible to prevent display device failure. can.

[Effect of the invention 1 According to the present invention, when a synchronization signal outside the operating range is input from the host computer or other related equipment while the display device is connected to the host computer or other related equipment and operated. The system now issues an audible warning to prevent display device failures due to synchronization signal input outside the operating range.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an example of the present invention, and FIG. 2 is a diagram for explaining the same. (1) is the horizontal synchronization signal input terminal, (2
) is the F/V converter, (3) (4) is the amplifier, (5) (6) (11) (14) (17) (19) is the resistor, (8) is the power supply terminal, (7 ) (18) is an AND circuit, (9) (12) (15) is a mono multi-bibreak-1 (lO) (13) (16) is a capacitor, (2
2) is a NOT circuit, (21) is a transistor, (20)
is a warning sound generation circuit. Applicant Seiko Electronic Industries Co., Ltd. Agent Patent Attorney Takayuki Hayashi Assistant Column 1 σ) 1
Figure 1

Claims (1)

[Claims] The output signal of the F/V converter that receives the horizontal synchronization signal as input is passed through a circuit consisting of one or more mono multivibrators connected in series or parallel to create a pulse, and the pulse is used to create a pulse. By activating the sound generation circuit, a sound warning device is activated when a synchronization signal outside the operating frequency range is input while the display device is operating, thereby preventing the display device from malfunctioning.