JPH01227739A - Electrocardiograph - Google Patents

Abstract

PURPOSE:To remove the induction noise components of a commercial frequency, on which an electrocardio-signal is superimposed, in an arbitrary attenuation quantity and to obtain an electrocardio-waveform in which a quality accuracy is good by varying the attenuation quantity of the commercial frequency components by means of an attenuation quantity variable type notch filter. CONSTITUTION:The electrocardio-signal is inputted through an amplifier 1 to an attenuation quantity variable type notch filter 2. The attenuation quantity variable type notch filter 2 functions as a hum filter, and the center frequency is 50-60Hz. The output of the attenuation quantity variable type notch filter 2 is sent to a recorder 3, and the electrocardio-waveform is recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrocardiograph, and particularly to a hum filter in an electrocardiograph.

[Conventional technology]

The hum filter of a conventional electrocardiograph has a constant attenuation amount at the center frequency due to a notch filter using a COR or the like with a fixed constant, and only two types can be selected: zero attenuation amount and constant attenuation amount.

[Problem to be solved by the invention]

In the conventional electrocardiograph mentioned above, regardless of the degree of influence of induced noise (hum) at the commercial frequency, the hum filter can only select two types of attenuation, so it may not be possible to completely remove induced noise, or However, due to excessive removal, frequency components that are the same as the commercial frequency in the electrocardiographic signal are also removed, resulting in a deterioration in the quality of the electrocardiographic waveform.

[Means to solve the problem]

The electrocardiograph of the present invention has a hum filter using a notch filter with variable attenuation.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In Figure 1, 1
is an amplifier at the input stage of the electrocardiographic signal. 2 is a variable attenuation type notch filter, which is used as a hum filter □, so its center frequency is 50 Hz or 60 Hz. 3 is a recorder (pen recorder, thermal plotter, etc.) for recording an electrocardiogram.

FIG. 2 shows an example of a circuit that can be used to construct the variable attenuation notch filter 2 in FIG. The amount of attenuation can be adjusted using the variable resistor 4. The whole of FIG. 2 corresponds to the notch filter 2 of FIG.

〔Effect of the invention〕

As explained above, the present invention uses a variable attenuation notch filter as a hum filter in an electrocardiograph to superimpose the same frequency component as the commercial frequency of the electrocardiogram signal on the electrocardiogram signal without excessively damaging it. Since the induced noise component of the commercial frequency can be removed with an arbitrary amount of attenuation proportional to the magnitude of the induced electrocardiogram, it is possible to record electrocardiographic waveforms with high quality and accuracy.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the configuration of an electrocardiograph according to the present invention, and FIG.
The figure is a diagram showing an example of the configuration of the variable attenuation type notch filter in FIG. 1. 1... Electrocardiographic signal input stage amplifier, 2...
Variable resistor for attenuation rotation adjustment. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] An electrocardiograph comprising a variable attenuation notch filter and variable attenuation of commercial frequency components.