JPS61234381A - Operation checker for doppler type ultrasonic detector - Google Patents

Abstract

PURPOSE:To check to ensure the operation of an ultrasonic detector, by arranging an oscillator for oscillating a signal with the frequency near that of an ultrasonic wave to be transmitted from a Doppler type ultrasonic detector and a transmitter to transmit an ultrasonic wave as driven by the output of the oscillator. CONSTITUTION:The frequency (f) of an ultrasonic wave received with a receiver 3 after reflected on an object B gives f=fo+ or -fd. After the received signal is amplified with an amplification circuit 4, the frequency fo as the output of an oscillation circuit 1 is mixed with the output of the amplification circuit 4 with a mixer 5 to detect the frequency shift fd. The movement of an object B is detected with a signal processing circuit 6 utilizing that the higher the moving speed (v) of the object B is, the higher the frequency fd is. The signal processing circuit 6 is made up of, for example, an F/V converter and a comparator and when a reference voltage is exceeded, an alarm 7 is driven. So to speak, it is possible to check to ensure the operation of a Doppler type ultrasonic detector depending on whether the alarm 7 sounds or not when the receiver 3 receives a signal, the frequency of which varies by the frequency shift fd enough to operate the comparator.

Description

[Detailed Description of the Invention] [Technical Field] The present invention provides a top-notch method for confirming that a Doppler type ultrasonic detector is operating normally. The present invention relates to an operation confirmation device for an ultrasonic detector.

[Background technology] Conventionally, in Doppler type ultrasonic detectors that use this type of ultrasonic waves to detect the presence and distance of objects, the ultrasonic waves themselves cannot be seen or heard with the eyes or ears. Therefore, the user cannot judge whether or not ultrasonic waves are really being transmitted into the space, which is unsettling for the user.In particular, Doppler type ultrasonic detectors used in crime prevention devices do not operate normally. It is necessary to be able to confirm what is being done. Therefore, in the past, a signal from a part of the circuit in the Doppler ultrasonic detector was extracted and a display device such as an LED was driven to inform the user that the circuit was operating normally. However, although this method can detect that the internal circuit is operating, it cannot detect whether the object detection operation is being performed normally.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems, and its object is to provide a Doppler ultrasonic detection system that can detect whether object detection operations are being performed normally. The purpose of the present invention is to provide a device for checking the operation of a device.

[Disclosure of the Invention 1 (Example) In describing the embodiment of the present invention, a Doppler type ultrasonic detector as an operation confirmation device will first be briefly described in the second drawing. This Doppler type ultrasonic detector 11 includes an oscillation circuit 1 that oscillates a signal that determines the frequency of the ultrasonic wave transmitted by the Doppler type ultrasonic detector, and a transmitter that transmits the signal oscillated by the oscillation circuit 1. A wave receiver 2, a receiver 3 that receives the ultrasonic waves transmitted from the wave transmitter 2 and reflected by the object B, an amplification circuit 4 that amplifies the output of the wave receiver 3, and the amplification circuit 4. A mixer 5 that mixes the output and the output of the oscillation circuit 1 and detects a difference signal, and an object B from the output of the mixer 5.
The object B is comprised of a signal processing circuit 6 that determines whether an object B exists or not, and an alarm 7 that issues an alarm when an object B is present based on the output of the signal processing circuit 6.

The operation of the Doppler type ultrasonic detector 11 having the above-described configuration is as follows. Let us assume that the frequency of the signal oscillated by the oscillation circuit 1 is fo, and that the transmitter 2 sends out an ultrasonic wave with a frequency of f0. Here, when the object B is moving at a speed V, the frequency deviation fd of the ultrasonic wave transmitted from the transmitter 2 and reflected by the object B is fd=2 vfo/, where the speed of sound is C. It becomes C. Therefore, the frequency r of the ultrasonic wave reflected by the object B and received by the receiver 3 is f = f o±fd. After this transfer signal is amplified by the amplifier circuit 4, the mixer 5 outputs the frequency f0, which is the output of the oscillation circuit 1, and the amplifier circuit 4.
The signal processing circuit 6 detects the movement of the object B using the fact that the frequency deviation fd increases as the moving speed V of the object B increases. It was something. This signal processing circuit 6 is composed of, for example, an F/V converter and a comparator, and the frequency deviation f
As d increases, the F/V converter output increases, and when this increase exceeds the reference voltage set in the comparator, the alarm 7 is driven. To detect the operating state of the Doppler ultrasonic detector 11 operating in this manner, the alarm 7 sounds when the transfer device 3 receives a signal with a frequency shifted by the frequency deviation fd at which the comparator operates. By doing so, it can be confirmed whether the Doppler type ultrasonic detector 11 is operating normally. Therefore, as shown in FIG. 1, the operation check device is a device that transmits a signal whose frequency is shifted by the frequency fd at which the comparator operates from the frequency f0 at which the oscillation circuit 1 of the Doppler type ultrasonic detector 11 oscillates. Just do it. Therefore, frequency f0
It consists of an oscillation circuit 8 that oscillates at ±fd, and a drive circuit 9 that drives a wave transmitter 10 with the output of the oscillation circuit 8. The operation of the above-mentioned operation confirmation device A is similar to the operation of the transmitting side circuit of the Doppler type ultrasonic detector 11, so the explanation will be omitted. Here, the switch SW is an operation switch that supplies power to the oscillation circuit 8 to operate the oscillation circuit 8, and when this switch SW is turned on, the ultrasonic wave of the frequency f0±fd is transmitted from the transmitter 10 of the operation check device A. is being transmitted,
The detection operation of the object B described above is performed using the Doppler ultrasonic detector 11.
When this occurs and the alarm 7 sounds, it means that the Doppler ultrasonic detector 11 is operating normally. In addition, by setting the frequency transmitted by the transmitter 10 of the operation confirmation device A to the minimum frequency deviation at which the above-mentioned comparator of the top 2 type ultrasonic detector 11 operates, that is, the frequency near the minimum detection sensitivity, Doppler type ultrasonic The operating sensitivity of the sound wave detector 11 can also be known.

[Effects of the Invention] As described above, the present invention includes an oscillator that oscillates a signal with a frequency near the frequency of the ultrasound transmitted by a Doppler type ultrasound detector, and an oscillator that is driven by the output of the oscillator to transmit the ultrasound. Since it is equipped with a transmitter that transmits the ultrasonic waves transmitted by the operation check device, the delivery device of the Doppler type ultrasonic detector receives the ultrasonic waves, and when the Doppler type ultrasonic detector operates normally, the Doppler type ultrasonic detector It can be confirmed that the Doppler-type ultrasonic detector is operating normally, the user does not have to worry about the operation, and the reliability of the Doppler-type ultrasonic detector can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, and FIG. 2 is a circuit configuration diagram of a Doppler type ultrasonic detection device whose operating state is confirmed according to the above. 3 is a receiver, 8 is an oscillation circuit, 9 is a drive circuit, 10 is a transmitter, 11 is a Doppler type ultrasonic detector, and A is an operation confirmation device. Agent Patent Attorney Ishi 1) Chief 7 Figure 1 Figure 2

Claims (1)

[Claims] (1) Doppler equipped with an oscillator that oscillates a signal with a frequency close to the frequency of the ultrasound transmitted by the Doppler ultrasound detector, and a transmitter that is driven by the output of the oscillator and transmits the ultrasound. Operation confirmation device for type ultrasonic detector.