JPS63128220A - Arithmetic circuit for distance measuring instrument - Google Patents

Abstract

PURPOSE:To eliminate an error caused by a fluctuation of the atmosphere, by sample-holding simultaneously input data. CONSTITUTION:Input signals V1A, V1B, V2A, V2B are held simultaneously by sample holding circuits 10a-10d by synchronizing with a pulse from a timing generator 11. Subsequently, the hold signal is inputted to a distance converter 16 through an A/D converter 13 due to a fact that a switch 12a is switched by synchronizing with a signal from the generator 11, converted to a distance and displayed on an indicator 17. In such a way, by sampling simultaneously the input signals, the fluctuation variation caused by the convection of the atmosphere is absorbed, and an error caused by the fluctuation can be eliminated.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an arithmetic circuit for a distance measuring device for measuring distance by an optical method mainly in places where there are atmospheric fluctuations, such as outdoors. 0 [Prior Art] Generally, triangulation is often used to measure the distance from a measurement point to a point to be measured. For this reason, two light sources are installed a predetermined distance apart at a point to be measured that is equidistant from the measurement point, and the distance between the light sources and the angle at which the light source is viewed from the measurement point are used to determine the distance between the measurement point and the point to be measured. The entire distance between them was calculated.

In this case, by changing the modulation conditions of the light source, the distance can be determined from the position of the light source that forms an image on the PSD element.

That is, with respect to the imaging position of one light emitting element shown in FIG. 2, a signal corresponding to the distance from one electrode 2a of the PSD element 2 to the imaging position t,
A signal corresponding to the distance from b to the imaging position, and a similar 21i type signal for the other light emitting element 1B, Accounting 4
types of signals can be obtained. This signal is transmitted to the light receiving circuits 3a and 3b.
The voltages VIA, VIB, V2A, and V2B are taken out independently and supplied to the arithmetic circuit 4. Then, in calculation time M, (VIA-V2A)/(VIA+V2A
) and (VIB-V2B)/(VIB+V2B
), the imaging point position on jEPsD2 is determined, and the distance is determined from this data.

[Problem that the invention seeks to solve]

There is no problem if such a conventional device is used indoors, but if it is used, for example, to measure the distance between trains when connecting trains,
When fluctuations due to atmospheric convection occur and the arithmetic circuit 4 is performing digital processing, it is difficult to sequentially take in four types of data, and data fluctuations caused by the fluctuations cause errors.

[Means for solving problems]

In order to solve this problem, the present invention provides a sample and hold circuit that simultaneously samples and holds data.

[Effect]

Fluctuations due to fluctuations are absorbed.

〔Example〕

FIG. 1 is a block diagram showing one embodiment of the present invention.

In the same figure, 10a to 10d are sample and hold times MT.
6C, the input signals VIA, VIB, V2A, and V2B are simultaneously held in synchronization with the pulses supplied from the timing generator 11. The held signal is sent to switch 1 in synchronization with the signal from timing generator 11.
A/D by switching 2a + 12b
The digitized signal is selected by the converter 13, converted to distance by the distance converter 16, and displayed on the display 17.
The desired distance is displayed.

The above operation will be explained in detail as follows. Assuming that the four electrical signals sampled by the sample and hold circuits 10a to 10d are α, β, γ, and δ in terms of amplitude modulation ratios due to fluctuations for each signal of 1 btcld%, the noise for each signal is as follows.

Noise for signal a...Noise for α・a signal...β・b Noise for signal C...
- Noise relative to the r'e signal...δ·d Therefore, the sampled signal input to the device is as follows.

5fa)=a+α'a”””””(I S(b)=b+β・b・・・・・・・・・(2) S<c
)=c+r−c−−°−−°°I−(3)8(d)=d
+δ・d・・・・・・・・・(4) On the other hand, PSD Shiko 2
The light spot position is expressed by the following equation.

Substituting the average value of each signal in this equation, we get the following: Since the four signals are sampled at the same time, the rate of amplitude change due to fluctuation ' is the same, and α = β = r = δ is achieved. The light receiving position is as follows.

=4- Since equations (7) and (8) do not include the item of fluctuation, the component due to fluctuation can be removed.

〔Effect of the invention〕

As explained above, since the input signals are sampled simultaneously, this invention has the effect of eliminating errors caused by atmospheric fluctuations.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing the overall configuration of a distance measuring device. 4... Arithmetic circuit, 10a to 10d... Su/pull hold circuit, 12a, 12b, 15"" switch, 13... A/D converter, 16... Distance converter. Procedural amendment (self-restraint 1. Indication of the case 1986 Patent Application No. 272808 2, Name of the invention Arithmetic circuit for distance measuring device 3, Relationship with the person making the amendment Patent Applicant name (name) Koito Kogyo Co., Ltd. 5, subject of correction (1) "Average value J" on page 5, line 6 of the specification is corrected to "value".

Claims (1)

[Claims] The PSD element receives signals from the first and second light emitters, which are provided at a predetermined distance apart from the measurement point and modulated under different conditions, and at this time, four types of signals are output from the PSD element. 1. An arithmetic circuit for a distance measuring device, characterized in that the arithmetic circuit for measuring a distance measures a distance using an output signal, and includes a sample-hold circuit that simultaneously samples and holds four types of signals.