RECORDING DEVICE WITH AUTOMATIC GAIN RANGE CHANGER AND D.C. CORRECTION MEANS

• US 3,699,948 A
• Filed: 05/14/1971
• Issued: 10/24/1972
• Est. Priority Date: 05/16/1970
• Status: Expired due to Term

• Current Assignee: Katunobu Takigawa, Masasada Honda, Tomiyoshi Ota
• Original Assignee: Katunobu Takigawa, Masasada Honda, Tomiyoshi Ota
• Inventors: Ota, Tomiyoshi, Takigawa, Katunobu, Honda, Masasada
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/143,552
• Time in Patent Office: 529 Days
• Field of Search: 128/2.6B,2.6G,2.6R,2.5Q 330/29,149 307/264
• US Class Current: 600/523
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: G01R 17/00 Measuring arrangements involving comparison with a reference value, e.g. bridge

Abstract

An automatic recording device incorporating a range changer and an asymmetrical DC level correcting means. The range changer automatically selects a gain capable of supplying the recorder, for example, with an electrocardiograph signal of suitable amplitude regardless of the amplitude of the detected electrocardiograph signal. The asymmetrical DC level correcting means corrects the DC level of the recorder so as to center the electrocardiogram on the recording chart.

Claims

1. A recording device comprising a bioelectrode for detecting an electrocardiograph signal, means for detecting a peak-peak value of said electrocardiograph signal, means for changing the range in which gain is automatically selected in accordance with said peak-peak value so as to obtain an electrocardiograph signal of suitable amplitude regardless of amplitude of detected electrocardiograph signal, means for detecting an asymmetrical DC signal of said electrocardiograph signal in order to record an electrocardiogram at the center of the recording paper and a recorder for recording said electrocardiograph signal passed through said range changer after superimposing said asymmetrical DC signal.

2. A recording device as claimed in claim 1 comprising at least one comparator having a standard voltage level, said comparator operating said range changer by means of the signal obtained by comparing said peak-peak value with said standard voltage level.

3. A recording device comprising a bioelectrode for detecting an electrocardiograph signal, means for detecting the positive peak value and the negative peak value of said electrocardiograph signal, means for obtaining a peak-peak value from said positive peak value and said negative peak value, means for changing the range in which gain is automatically selected in accordance with said peak-peak value so as to obtain an electrocardiograph signal of suitable amplitude regardless of amplitude of detected electrocardiograph signal, means for detecting an asymmetrical DC signal of said electrocardiograph signal from said positive peak value and said negative peak value and a recorder for recording said electrocardiograph signal passing through said range changer after superimposing said asymmetrical DC signal.

4. A recording device as claimed in claim 3 wherein said means for detecting asymmetrical DC signal comprises two series resistors connected between the outputs of said positive and negative peak value detecting means and an asymmetrical DC level correcting means for correcting the level of said asymmetrical DC signal detected at the junction of said two resistors.

5. A recording device as claimed in claim 4 wherein said DC level correcting means corrects the level of said asymmetrical DC signal in unison with said range changer.