JP2550649Y2 - Trigger signal generation circuit - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a recording apparatus for converting an input analog signal into a digital signal and performing various recordings based on the converted digital signal. The present invention relates to a recording apparatus having a trigger function for generating a trigger signal when the number reaches a threshold value and sending the trigger signal to a CPU to perform desired control on the recording means.

[0002]

2. Description of the Related Art Conventionally, this type of recording apparatus converts an input analog signal into a digital signal by an A / D converter, transmits the digital signal to a CPU, and outputs the signal in a desired form such as a waveform and a numerical value from a recording means. It is configured. For example, when measuring a vibration phenomenon or the like using a conventional recording apparatus, since it is not known when the phenomenon occurs, it is necessary to always feed the recording paper, and the recording paper other than the necessary part may be extremely wasted. Was. In order to solve these problems, the level of an input signal for recording (hereinafter referred to as a trigger level) is set in advance, and when the input signal reaches this set level,
A function (trigger function) for performing a recording operation was provided. FIG. 2 shows a trigger signal generation circuit of a conventional device. In the figure, reference numeral 1 denotes a reference voltage generation circuit of an A / D converter;
Is an A / D converter, 3 is a comparator, 4 is a digital potentiometer, and 5 is a variable resistor. The digital potentiometer 4 is configured to set a trigger level, and to adjust a settable range of the trigger level by the variable resistor 5. An input signal input from the analog input unit is converted into a digital signal by the A / D converter 2 and sent to the CPU. At the same time, the input signal is transmitted to the comparator 3 as an input signal. When the input signal reaches the trigger level set by the digital potentiometer 4, the comparator 3 generates a trigger signal and sends it to the CPU. The CPU that has detected the trigger signal is configured to perform various controls on the recording unit.

[0003]

[Problems to be Solved by the Invention] In the conventional device,
The setting range of the trigger signal had to be equal to the voltage of the reference voltage generating circuit. This is because the reference voltage of the reference voltage generating circuit 1 is a unique voltage value determined by the type of the A / D converter to be used, and the range of the voltage of a signal that can be input is also determined by this. Further, in order to be able to set the trigger level in the entire range of the voltage of the input signal, the set range of the trigger level must be equal to the voltage of the reference voltage generating circuit. An A / D converter used for this purpose There is a problem that the variable resistor 5 must be adjusted according to the above. Further, when the voltage generated by the reference voltage generation circuit fluctuates, different reference voltages are input to both, which causes an error. The present invention has been made to solve such a problem, and in a trigger signal generating circuit of a recording apparatus,
It is an object of the present invention to provide a recording apparatus which does not require adjustment of a setting range of a trigger level and can prevent an error.

[0004]

In order to solve the above-mentioned problems, a trigger signal generating circuit according to the present invention uses an output voltage of a reference voltage generating circuit of an A / D converter as a reference voltage of a digital potentiometer. Is the most important feature.

[0005]

In the trigger signal generator configured as described above, the A / D converter and the digital potentiometer are connected in parallel to the reference voltage generator. As a result, the setting range of the trigger level becomes equal to the reference voltage of the A / D converter, and it is not necessary to adjust the setting range of the trigger level.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A trigger signal generator for a recording apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing an embodiment of the present invention, wherein 1 is a reference voltage generating circuit, and 2 is an A / D.
A converter, 3 is an analog comparator, and 4 is a digital potentiometer. In the figure, S represents a signal,
S1 is a reference voltage, S2 is an analog input signal, S3 is a comparison input signal, S4 is a trigger signal, and S5 is a digital output signal. An analog input signal S2 taken from input means (not shown) is input to the A / D converter 2 via an amplifier or the like (not shown), converted into a digital signal S5, and transmitted to the CPU. At the same time, the analog input signal S2 is transmitted to the comparator 3, which compares the comparison input signal S2 transmitted from the digital potentiometer 4.
3 and the analog input signal S2, and when S2 reaches S3, a trigger signal S4 is generated and transmitted to the CPU. When the CPU receives the trigger signal, the CPU transmits a predetermined control signal to the recording unit.

The level of the trigger signal is set by changing the resistance value of the digital potentiometer 4, and the comparator 3 sets the trigger level S3 set thereby.
And an analog input signal S2, and when S2 reaches the value of S3, a trigger signal S4 is transmitted to the CPU. The input voltage of the digital potentiometer 4 is set as the reference voltage S1 from the reference voltage generating circuit 1, and the input voltage of the A / D converter 2 and the input voltage of the potentiometer 4 are made common, so that the trigger level can be set within the range of the A / D converter. 2 is always equal to the reference voltage, and adjustment of the setting range of the trigger level is unnecessary.

[0008]

[Effect of the Invention] As described in detail above, according to the present invention, A
By connecting the / D converter and digital potentiometer in parallel to the reference voltage generation circuit, the trigger level setting range is configured to be equal to the A / D converter reference voltage, and the trigger level setting range does not need to be adjusted. It can be.

[Brief description of the drawings]

FIG. 1 is a block diagram of a trigger signal generating circuit according to the present invention.

FIG. 2 is a block diagram of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reference voltage generation circuit 2 A / D converter 3 Analog comparator 4 Digital potentiometer 5 Variable resistor

Claims (1)

(57) [Scope of request for utility model registration] An A / D converter for converting an input analog signal into a digital signal, a reference voltage generation circuit for supplying a reference voltage to the A / D converter, and a comparison signal which can be set to a desired value And comparing the input analog signal with the comparison signal from the variable resistor to determine when the analog signal reaches the value of the comparison signal.
A comparator that sends a trigger signal to the PU, and a CPU (central processing unit) that performs various processes on the input signal
A trigger signal generating circuit, wherein an output voltage of the same reference voltage generating circuit as a reference voltage of the A / D converter is input to the variable resistor as a reference voltage. .