JP2016109657A - Water content meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measurement device in which, when measuring a water content in a wall, a ceiling and a floor, using a wave, capable of reliably receiving a reception signal while suppressing an output wave to a weak range, and when diffusing a transmission frequency with a triangular wave, suppressing output level of both ends of a band to a weak level, so that the output level does not become high at both ends, so that whole reception sensitivity is not reduced.SOLUTION: Reverse direction attenuation of a reception amplifier (3) is used as part of weakening of an output wave, and in addition, when diffusing a transmission frequency with a triangular wave, a low pass filter (4) is used as means for suppressing increase of output level, at a high end of a band.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for measuring moisture in walls, ceilings, and floors using weak radio waves in an apparatus that uses radio waves.

As a method of exploring the inside of buildings made of construction materials such as wood and cement, such as FMCW radar and pulse radar, based on the strength and phase information of the radio waves that radiated and reflected inside the walls and reflected inside There is a way to examine the internal structure.
At this time, the intensity and phase of the reflected radio waves differ depending on the moisture of the building, so this change can be observed as the moisture content.

  In the method of using such radio waves, the range of frequencies that can be used is limited by the radio wave method so as not to interfere with other communications, and due to this restriction, short distances within 1 m are measured with high resolution. I couldn't do anything, but could only detect relatively distant objects.

  In order to increase the distance resolution, the frequency range used was expanded to 10 GHz, the distance resolution was reduced to 15 mm, and the output power was reduced by spreading the radio waves at high speed so as not to disturb other communications. By using the reverse isolation of the amplifier to output radio waves from the receiving amplifier, it is further weakened to a weak level and at the same time efficiently amplifies the received signal from the receiving amplifier.

  Since a single antenna can be used for transmission and reception, the measurement location can be reduced. Since the output radio wave is weak, there is no limit to the frequency used, and high distance resolution can be achieved.

It is a block diagram of the present invention.

Hereinafter, embodiments for carrying out the invention will be described.
A low-pass filter (4) for preventing the jumping of the high frequency range of the transmitted radio wave by connecting the VCO (1) with a triangular wave generator (2) for oscillating at an oscillation frequency of 10 GHz to 20 GHz. The transmission radio wave leaking out from the receiving amplifier input side is radiated from the antenna (5) to the surface to be measured.
The radio wave reflected from the measured surface is received by the antenna (5), and the frequency difference between the received radio wave amplified by the receiving amplifier (3) and the transmitted radio wave from the VCO (1) is detected by the detector (6). Take out the standing wave.
The CPU (7) calculates the internal structure and humidity from the magnitude and phase information of the detected low frequency voltage and displays it on the display (8).

(1) VCO
(2) Triangular wave generator (3) Receiving amplifier (4) Low pass filter (5) Antenna (6) Detector (7) CPU
(8) Display

Claims (3)

  By transmitting a radio wave toward the object, receiving a reflected wave from the object, and analyzing the received signal, the state or physical characteristics of the object, that is, the distance to the object, the relative speed to the object A device for measuring a shape, an internal structure, and the like, wherein a receiving unit for receiving a reflected wave includes at least a local oscillator and an antenna, and an output of the local oscillator is reversely transmitted to the receiving unit, A measuring device that uses a signal radiated from an antenna as a transmission wave and does not have a dedicated circuit and path for transmission.   The apparatus according to claim 1, wherein frequency modulation is performed on the local oscillator.   The apparatus according to claim 1 or 2, further comprising a signal analysis unit for measuring water content of the object.

Images