JPS60214121A - Analog-digital converter - Google Patents

Abstract

PURPOSE:To attain the processing exceeding the rated resolution of an A/D converter by providing a subtraction circuit and a subtraction deciding means deciding that a digital signal data exceeds a prescribed level. CONSTITUTION:Since an input analog value to a sensor or the like is lower than a prescribed level (a) at the initial state, the subtraction circuit 12 is not activated. Thus, relation of x=c is obtained at an operating means 14 for the data (x) desired to be obtained. When the analog value reaches the prescribed level (a), a subtraction deciding means 15 is activated and an analog value reaches a level (b). Thus, the operation at (c) in Fig. is obtained as x=a+(c'-b). When the analog value is decreased and the level (c) is lower than the level (b), the operation of the deciding means 15 is stopped and the operation of the data to be obtained restores to the relation of x=c. Thus, the processing exceeding the rated resolution of the A/D converter is attained.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an analog-to-digital conversion circuit for digitizing analog signals output from various types of sensors, etc., and using the digitized signals for digital display, judgment, etc. It is.

(Constitution of Conventional Example and its Problems) The constitution and problems of the prior art closest to the present invention will be described with reference to the drawings.

FIG. 1 shows a conventional analog-to-digital converter. In FIG. 1, 1 is an input such as a sensor, 2 is an amplifier, 3 is a Φ converter, 4 is a control means for controlling a display, etc., and 5 is a terminal such as a display. The relationship between the resolution of the /D converter 3 and the resolution of the control means 4 that controls display etc. is such that the control means 4 cannot function beyond the rated resolution of the converter 3.

For example, an 8-bit converter has a resolution of 256 steps, and if detailed detection of input 1 of a sensor or the like is required, detection can only be performed with the rated resolution of 256 steps.

In addition, in terminals such as displays, "8 bits" or
It does not have a display function of "256" or more.

(Object of the invention) The present invention eliminates the drawbacks of the above-mentioned conventional example.
It has a processing capacity that exceeds the rated resolution of the converter, and is intended to detect detailed input changes from sensors, etc.

(Structure of the Invention) The present invention comprises a subtracting circuit for an input such as a sensor, a φ converter for digitizing an analog input, a subtraction determining means for determining whether digital signal data exceeds a certain level, and a This analog-to-digital conversion device is equipped with arithmetic means for calculating the digital signal of the converter based on the signal of the determination means, and is capable of processing at a resolution higher than the rated resolution of the converter.

(Description of Embodiment) The configuration of an embodiment of the present invention will be described with reference to the drawings from FIG. 2 onwards.

Figure 2 shows the function! Lower figure 2, sensor input 1
The analog signal obtained from 1 is digitized by a subtractor 13 through a subtraction circuit 12. The digital signal is
The signal is sent to the calculation means 14 and the subtraction judgment means 15, and the signal from the subtraction judgment means 15 is fed back to the subtraction circuit 12. The signal passed through the calculation means 14 is processed by a terminal control means 16 such as a display, and then sent to a display terminal.

The present invention has the above-mentioned configuration, and a circuit diagram of the main part thereof is shown in FIG. Inside the microcombinator A, the above-mentioned calculation means 14, subtraction determination means 15, and terminal control means 16 such as a display are housed. The subtraction circuit 12 is constructed of a circuit using an amplifier.

The specific operation will be explained using the analog value change of the input of the sensor etc. in FIG. 4 and the flowchart in FIG. 5.

In the initial state, the analog value of the input of the sensor, etc. is lower than a certain level a, and since the subtraction circuit 12 is not operating, the data X to be requested is calculated by the calculation means 14 as
C". When the analog value reaches a certain level "a", the subtraction determination means 15 operates, and the analog value becomes "Birepel". This "b" is determined as the calculation parameter, and "
The operation in C'' can be expressed as x=a0(c'-b).

Also, when the analog value decreases and the "C# level becomes smaller (calculation 0) c'-b", the operation of the subtraction judgment means 15 is stopped and the calculation of the data that can be requested is X = "c". Return to ″.

Next, this example was applied to an electronic blood pressure monitor using an 8-pin (255-step) converter.
An example in which the intermittent instruction interval IWrInHp is displayed over Hg will be described.

FIG. 6 shows that even when the blood pressure value (analog value) exceeds the 8-bit resolution, subtraction is performed so that the display is performed at a level that can be processed by the converter.

In this example, there is one constant level judgment value (a in FIG. 6) in 250 steps within 8 steps (255 steps f). This level is the level determined by the subtraction determining means 15 in the micro converter A on the data processed by the converter 13.

The subtraction determining means 15 outputs a signal from the microconbeater A, and the subtraction circuit 12 operates.

The level after the subtraction circuit operates (b in Figure 6) is stored in the micro converter through the ~ raw converter, and thereafter (during the subtraction circuit operation) the pressure at point C (C in Figure 6) is determined by the following formula: Calculate.

x=c'+ (a-b) If c'=220, a=250, b=200, x
= 220 + (250-200) =, 270
wnHll, this operation is conventionally 255 ta
The one that could only display up to nHfj was 300 tt.
It is possible to display up to anHg.

(Effects of the Invention) As described above, according to the present invention, processing exceeding the rated resolution of the converter is possible, and detailed changes in analog input exceeding the resolution of the converter can be detected and displayed. You can get the desired effect.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of, for example, a display device using a conventional analog-to-digital converter, FIG. 2 is a block circuit diagram of, for example, a display device using the analog-to-digital converter of the present invention, and FIG. 3 is a block circuit diagram of the same display device. The circuit diagram of the embodiment, FIG. 4 is a diagram for explaining the operation of the calculation means when the subtraction determination means of the same display device operates, and FIG. 5 shows the functions of the calculation means and the subtraction means of the device of the present invention. Flowchart, No. 6
The figure is an explanatory diagram of the operation when the device of the present invention is used as an 8-bit resolution converter in an electronic blood pressure monitor. 11...Input of operator etc., 12...Subtraction circuit, 1
3... Analog-digital converter, 14... Arithmetic means, 15... Subtraction determination means, 16... Terminal control means, 17... Display, A... Microconbeater. Figure 1 Figure 2 Figure 3 Figure 4 Familiarization OFF 'ON' OFF Figure 5

Claims (1)

[Claims] A subtraction circuit for an input such as a sensor, an analog-to-digital (A/1) converter for digitizing an analog input, a subtraction determination means for determining whether digital signal data exceeds a certain level, and the subtraction determination means. an analog-to-digital (pv'D) converter for calculating a digital signal based on the signal from the analog-to-digital (pv'D) converter.
Digital conversion device.