True dual-timebase arrangement for an oscilloscope

• US 20030218612A1
• Filed: 05/22/2002
• Published: 11/27/2003
• Est. Priority Date: 05/22/2002
• Status: Abandoned Application

• Current Assignee: Kenneth P. Dobyns
• Original Assignee: Kenneth P. Dobyns
• Inventors: Dobyns, Kenneth P.
• Application Number:
  US10/154,613
• Publication Number:
  US 20030218612A1
• Time in Patent Office: Days
• US Class Current: 345/440
• CPC Class Codes: G01R 13/345 for displaying sampled signals by using digital processors by intermediate A.D. and D.A. convertors (control circuits for CRT indicators)

Abstract

A dual timebase feature for digital storage oscilloscope includes an A/D converter for producing digital samples of a signal under test. The digital samples are applied to a first decimator for decimating the samples. A second decimator coupled to the output of the first decimator further decimates the samples. A pair of gates selectively couples the outputs of the first and second decimators to a memory. A controller controls one gate to select a high data rate record having a length shorter than an entire data record for storage in memory and for display as a zoom (i.e. detailed) record, and controls the other gate to select a low data rate record encompassing substantially all of said entire data record, for display as an overview record. The subject apparatus produces two data records of different data rates and encompassing different time periods.

Claims

1. A dual timebase digital storage oscilloscope, comprising:

an A/D converter for producing digital samples of a signal under test;

a first decimator having an input coupled to an output of said AID converter for receiving and decimating said samples;

a second decimator having an input coupled to an output of said first decimator for receiving said decimated samples and further decimating said decimated samples;

a first gate having an input coupled to an output of said first decimator, and an output;

a second gate having an input coupled to an output of said second decimator, and an output;

a memory coupled to said outputs of said gates for receiving and storing signal;

samples; and

a controller for controlling said first gate to couple a high data rate record having a length shorter than an entire data record to said memory, and controlling said second gate to couple a low data rate overview record of substantially all of said entire data record to said memory.

2. The dual timebase oscilloscope of claim 1 wherein:

said high data rate record is produced by said first decimator.

3. The dual timebase oscilloscope of claim 1 wherein:

said low data rate overview record is produced by said second decimator.

4. The dual timebase oscilloscope of claim 1 wherein:

said low data rate overview record contains more samples than said high data rate record.

5. The dual timebase oscilloscope of claim 1 wherein:

said high data rate record is a zoom record

6. A dual timebase digital storage oscilloscope, comprising:

an A/D converter for producing digital samples of a signal under test;

a decimator having an input coupled to an output of said AID converter for receiving and decimating said samples and producing said first decimated samples at a first output;

said decimator having a second output for producing further decimated samples;

a first controlled switch having an input coupled to said first output of said decimator, and an output;

a second controlled switch having an input coupled to said second output of said decimator, and an output;

a memory coupled to said outputs of said controlled switches for receiving and storing signal;

samples; and

a controller for controlling said first controlled switch to couple a high data rate record having a length shorter than an entire data record to said memory, and controlling said second controlled switch to couple a low data rate overview record of substantially all of said entire data record to said memory.

7. The dual timebase oscilloscope of claim 6 wherein:

said high data rate record is produced at said first output of said decimator,

said high data rate record being a zoom record.

8. The dual timebase oscilloscope of claim 6 wherein:

said low data rate overview record is produced at said second output of said decimator.

9. The dual timebase oscilloscope of claim 6 wherein:

said low data rate overview record contains more samples than said high data rate record.

10. A method of providing a true dual timebase feature for digital storage oscilloscope, comprising the steps of:

producing digital samples of a signal under test;

receiving and decimating said samples and producing first decimated samples;

further decimating said first decimated samples to produce further decimated samples;

storing a predetermined amount of said first decimated samples in a memory;

storing said further decimated samples in said memory;

displaying said further decimated samples as an overview record; and

displaying said stored amount of said first decimated samples as a zoom record.

11. A dual timebase digital storage oscilloscope, comprising:

an A/D converter for producing digital samples of a signal under test;

a first decimator having an input coupled to an output of said A/D converter for receiving and decimating said samples;

a second decimator having an input coupled to an output of said first decimator for receiving said decimated samples and further decimating said decimated samples;

a gate having an input coupled to an output of said first decimator, and an output;

a memory having a first input coupled to said output of said gate, and a second input coupled to an output of said second decimator, for receiving and storing signal samples; and

a controller for controlling said gate to couple a high data rate record having a length shorter than an entire data record to said memory, and controlling storage of a low data rate overview record of substantially all of said entire data record in said memory.