Electronic measuring instrument combining an oscilloscope and a digital multimeter

• US 4,034,291 A
• Filed: 04/14/1975
• Issued: 07/05/1977
• Est. Priority Date: 04/14/1975
• Status: Expired due to Term

• Current Assignee: Tektronix Incorporated (Fortive Corp.)
• Original Assignee: Tektronix Incorporated (Fortive Corp.)
• Inventors: Allen, David William, Borchert, Marshall Bond
• Primary Examiner(s): Rolinec, Rudolph V.
• Assistant Examiner(s): Karlsen, Ernest F.
• Application Number:
  US05/567,798
• Time in Patent Office: 813 Days
• Field of Search: 324/121 R, 324/99 D, 324/112, 324/115, 324/157, 325/367
• US Class Current: 324/121.00R
• CPC Class Codes: G01R 13/20 Cathode-ray oscilloscopes
• CPC Class Codes: G01R 15/08 Circuits for altering the measuring range

Abstract

An oscilloscope and a digital multimeter are combined in a single housing to provide a portable electronic measurement instrument wherein a substantial portion of circuitry is common to both measurement systems. A cathode-ray tube provides the display for both waveform and alpha-numeric information.

Claims

1. A portable electronic measuring instrument, comprising:

input circuit means including preprocessing means for converting a plurality of input signals of different measurement quantities to voltage signals;

analog processing means for receiving said voltage signals and producing an analog waveform signal therefrom;

digital processing means for receiving said voltage signals and producing numerical values thereof, said digital processing means including a Gm conversion unit, an RMS conversion circuit, and an A-D converter; and

display means for selectively displaying said analog waveforms and said numerical values.

2. The instrument according to claim 1 wherein said input circuit means includes at least one amplification stage for providing a buffer between said preprocessing means and said analog and digital processing means.

3. The instrument according to claim 1 wherein said preprocessing means includes means for scaling said input signals to within a predetermined amplitude range.

4. The instrument according to claim 1 wherein said digital processing means further includes an alpha-numeric character generator circuit.

5. A portable measuring instrument including an oscilloscope and a digital multimeter, comprising:

input circuit means for receiving voltage and current signals, said input circuit means including means for converting said current signals to voltage signals;

analog processing means including a vertical amplifier channel and a sweep generator connectable to said input circuit means for receiving said voltage signals and generating analog waveforms therefrom;

digital processing means including an A-D converter and an alpha-numeric character generator connectable to said input circuit means for receiving said voltage signals and generating characters corresponding to the numerical values thereof; and

display means including a cathode-ray tube for selectively displaying said analog waveforms and said alpha-numeric characters.

6. The instrument according to claim 5 wherein said input means includes impedance elements and at least one amplification stage for determining the amplitude range of said instrument.

7. The instrument according to claim 5 wherein said input means includes current generator means for producing a predetermined output current to a resistance being measured.

8. The instrument according to claim 5 wherein said digital processing means further includes a Gm conversion circuit and an RMS conversion circuit.