JPS5918545Y2 - Security device signal processing circuit - Google Patents

Description

[Detailed description of the invention] The present invention is a security device for detecting illegal intruders by receiving an ultrasonic signal from a transmission transducer reflected by an object using a delivery transducer. This invention relates to signal processing circuits.

Conventionally, this type of security device has been prone to malfunction due to vibrations caused by large trucks passing by, the initial vibrations of an earthquake, and noise from the power supply.

These noise signals are all pulse signals of extremely short duration, and moreover, two or more signals are rarely generated within a relatively short period of time.

The present invention was devised in view of these points, and is designed to provide an output when a pulse signal with a width greater than a predetermined width is generated, or when two or more predetermined pulse signals are generated. be.

An embodiment of the present invention will be described with reference to the drawings.

Reference numeral 1 denotes an input signal terminal, and the input terminal 1 receives a certain amount of signals, specifically 0.
Only pulse signals of 7 seconds or longer are sent.

This input terminal 1 is branched by voltage dividing resistors 2 and 3, one is connected to an output terminal 5 via a switching circuit 4, and the other is connected to a timer 6, which controls the switching circuit 4. It looks like this.

The timer 6 includes a backflow element diode 7, a capacitor 8, a resistor 9, and a transistor 10, the collector of which is connected to a power source via a resistor 11.

Further, the switching circuit 4 includes a reverse current element diode 12, a transistor 13, resistors 14, 15, and a capacitor 16.

Next, the operation will be explained based on FIG.

In addition, in FIG. 2, time t1 is the time from when the input signal is input until the timer 6 starts operating, and specifically, it is 0.
．． 7 seconds, and time t2 is the time from when the timer 6 starts operating until when the switching circuit 4 starts operating,
Specifically, it is 0.1 to 0.5 seconds, and time t3 is the time from when the human pulse signal is input until the timer 6 stops operating, and specifically, is 10 seconds.

First, in Figure 2a, the pulse width is larger than tl (
It is assumed that an input pulse signal smaller than t1+t2) enters input terminal 1.

When this input pulse signal is input, the capacitor 8 starts charging, and at time t1, the transistor 10 is turned on and the timer 6 starts operating.

When transistor 10 is turned on, capacitor 16 rapidly discharges through resistor 14.15 during time t2, turning off transistor 13 as switching circuit 4.

However, since the input pulse signal disappears before the transistor 13 is turned off, no output is applied to the output terminal 5, and therefore the self-holding relay of the alarm (not shown) does not operate.

If no human pulse signal is received before the elapse of t3, the capacitor 8 is discharged, the transistor 10 is turned off, the operation of the timer 6 is stopped, and the transistor 13 of the switching circuit 4 is turned on to restore the original state. return to the state of
Waits for the next input pulse signal.

Next, in FIG. 2, during time t3 while the timer 6 is operating, the second input pulse signal is input to the input terminal 1.
When the timer 6 enters, the transistor 10 of the timer 6 is turned on and the transistor 13 of the switching circuit 6 is turned off, so that the input pulse signal is directly output to the output terminal 5.

This output activates a self-holding relay (not shown) and activates an alarm.

Next, in Fig. 2C, if the width of the first input pulse signal is (t1+t2) or more, the output is (t1+t2).
Occasionally, rain occurs immediately, and a self-holding 1° relay (not shown) is activated, which activates the alarm.

Since the present invention is constructed as described above, it does not operate incorrectly due to the initial vibrations of daily life earthquakes, power supply noise signals, etc., and operates accurately as a crime prevention device.

[Brief explanation of the drawing]

FIG. 1 is an electrical circuit diagram showing one implementation of the signal processing circuit according to the present invention, and FIGS. 2a, 1) and c are time charts for the fourth operation.

Claims (1)

[Scope of utility model registration request] It is equipped with a timer 6 that is activated by an input pulse signal of a width greater than a predetermined width and returns to the previous state after a certain period of time, and a switching circuit 4 that operates with a slight time delay after the activation of the timer 6 and takes out the input pulse signal as an output. A signal processing circuit for a security device characterized by: