JP2535315Y2 - Dot array recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application field] The present invention sequentially prints a line-by-line print signal in which a baseline signal is superimposed on an analog input signal on a dot array head in which dot print elements are arranged in a line. The present invention relates to a dot array recorder in which an analog input signal waveform is drawn together with a base line when supplied.

[Conventional technology]

In a recorder in which one or a plurality of base lines corresponding to the number of channels are drawn on this type of recording paper, a print line having an input signal of a zero level should coincide with this base line. However, when an apparatus that outputs an analog signal is connected to the input terminal of the recorder, if an offset level occurs, the print line is shifted from the base line.

[Problems to be solved by the invention]

For this reason, there has conventionally been provided a dot array recorder provided with a DC level adjuster, whereby the zero level print line and the base line are made to coincide with each other by manual adjustment.

The present invention has been made in view of the above, and has as its object to provide a dot array recorder that automatically compensates for an offset.

[Means for solving the problem]

According to the present invention, in order to easily achieve this object by an open loop circuit configuration, as shown in FIG. 1, the operation is started in response to the input of an offset compensation command signal for commanding the start of the offset compensation operation. Then, in response to a plurality of timer signals sequentially output from an attached timer means, the output signal of the A / D converter 1 is sequentially acquired a plurality of times, and an average value of the analog input signal level with respect to the zero level input is calculated. Average level calculating means 2, offset level storing means 3 for storing the calculated average value as an offset level, and A / D converter 1 so that the base line is recorded so as to coincide with the zero-level input print line. A subtraction means 4 for supplying a signal obtained by subtracting the stored offset level from the output signal to the print signal creation means 5 is provided in the dot array recorders 1, 5 to 7. It was.

[Action]

The print signal creation means 5 superimposes the base line 7a on the recording paper 7 with respect to the dot array head 6, and draws a waveform of the analog input signal.

If the offset compensation command signal is input before the generation of the analog waveform signal when the printing line corresponding to the zero level input of the analog input signal is shifted from the base line 7a due to the offset, the average level calculation means 2 outputs the output of the A / D converter 1. The signal is sequentially taken in response to a plurality of timer signals, taken in a plurality of times, averaged, an offset level is calculated, and stored in the offset level storage means 3. After that, the subtraction means 4 will be A / D
A signal obtained by subtracting the offset level from the output signal of the converter 1 is supplied to the print signal creating means 5, and the base line is made to coincide with the zero-level input print line.

〔Example〕

FIG. 2 shows a thermal array recorder for three channels, for example. The A / D converter 11 in the figure, the preamplifier 10 ₁ to 10 ₃ belonging to each channel is preceded. Reference numeral 20 denotes a well-known print signal generation unit configured using a CPU, and a sensitivity processing unit 21 that varies an amplitude of an analog input signal according to a set state of a sensitivity key, and a paper feed unit according to a position key set. A position processing unit 22 that adjusts the printing position in a direction orthogonal to the direction, a waveform clamp processing unit 23 that clips the waveform of the upper and lower limit positions on the recording paper 28,
A baseline signal generator 24 for generating a baseline signal for printing the base line 29 _{1-29 3} for each channel, the print signal output unit 25 for outputting the dot printing signal superimposed baseline signals to these waveform signals to the thermal array head 26 It is composed of

CPU 30 has ROM 31, RAM 32, timer 33, I / O port 34
Are attached, the above-mentioned average level calculation means,
It constitutes a microcomputer for the offset level storage means and the subtraction means. This CPU can also be used as the CPU constituting the above-described print signal creation means.

When an offset compensation key (not shown) is operated, the CPU 30 takes in the offset compensation command signal (FIG. 3a) and starts a compensation operation. That is, by operating according to the program stored in the ROM 31, every time four timer signals (FIG. 3b) at 1 ms intervals are fetched from the timer 33, the output signal of each channel from the A / D converter 11 is output. The data is stored in the RAM 32 together with a code corresponding to the offset to which side with respect to the zero level. Then, 4 of each channel
The output signals of the individual channels are averaged, and the average value of each channel is stored as an offset level. Further, the offset level of the assigned channel stored for the input signal input from the A / D converter 11 is subtracted to generate a print signal generating means.
Transfer to 20.

Next, the operation of the thus-configured thermal array recorder will be described.

A print line input signal level of the preamplifier 10 ₁ to 10 ₃ is printed on the recording paper 28 in a state of zero is printed on the base line 29 _{1-29 3.} However, for example, if the polygraph body to record three kinds of biological signal is connected, the offset at the zero level state waveform signal is not generated in the output terminal occurs, ₁ baseline 29 as is the corresponding level ~ Two
9 Line printing is shifted from ₃ .

On the other hand, when the offset compensation key is operated at a stage before the biological waveform signal is still supplied in the connected state of the polygraph main body, an offset compensation operation described below is performed.

That is, the CPU 30 outputs the output signal of each channel corresponding to the offset amount from the zero level from the A / D converter 11 by 1 m.
The data is acquired four times at s intervals and averaged to avoid the occurrence of an error in the offset value due to noise. Then, the offset level of each channel is held, and a signal obtained by subtracting the offset level from the biological signal of each channel to be input thereafter is printed. As a result, the offset level is offset in the recording paper 28, and thus the zero level line is
29 _{1-29 three} upper or shifted to the lower recording it is eliminated.

In the above-described embodiment, the offset command signal is
It is also conceivable that, instead of a manual operation, it is automatically generated at the start of operation, for example, in response to a recording start signal.

[Effect of the invention]

As described above, according to the present invention, with the simple circuit configuration of the open loop, the deviation of the zero level of the recording waveform from the base line due to the offset of the input signal is automatically and accurately suppressed by suppressing noise. You.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating the configuration of a dot array recorder according to the present invention, FIG. 2 is a diagram illustrating the configuration of a thermal array recorder according to an embodiment of the present invention, and FIG. FIG. 6 is a diagram illustrating an operation of the example. 1, 11 A / D converter, 6 dot array head, 7, 28 recording paper, 26 thermal array head.

Claims (1)

(57) [Scope of request for utility model registration] An A / D converter for digitizing an analog input signal on a dot array head in which dot printing elements are arranged in a line, and a base line signal superimposed on the digitized signal to print each line. In the dot array recorder which prints the signal of the input analog signal together with the base line by attaching the print signal generating means for generating the signal and supplying it to the dot array head sequentially, the offset compensation commanding the start of the offset compensation operation The operation is started in response to the input of the command signal, and the output signal of the A / D converter is sequentially taken a plurality of times in response to a plurality of timer signals sequentially outputted from the attached timer means, and the zero level input is performed. Average level calculating means for calculating the average value of the analog input signal level with respect to, and the calculated average value as an offset level An offset level storing means for storing the offset level stored in the output signal of the A / D converter so that the base line is recorded so as to coincide with the zero-level input print line. A dot array recorder, comprising: a subtraction unit that supplies the print signal to the print signal creation unit.