Waveform display apparatus of frequency sweep type for facilitating display of a high definition waveform

• US 5,579,463 A
• Filed: 02/08/1995
• Issued: 11/26/1996
• Est. Priority Date: 03/30/1990
• Status: Expired due to Term

• Current Assignee: Anritsu Corporation
• Original Assignee: Anritsu Corporation
• Inventors: Takano, Mitsuyoshi, Katayama, Aiichi
• Primary Examiner(s): Jankus, Almis R.
• Application Number:
  US08/385,554
• Time in Patent Office: 657 Days
• Field of Search: 395/140, 395/133-139, 395/128, 395/155, 395/161, 345/133-135
• 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)
• CPC Class Codes: G01R 23/16 Spectrum analysis; Fourier analysis
• CPC Class Codes: G01R 23/163 adapted for measuring in circuits having distributed constants
• CPC Class Codes: G01R 23/173 Wobbulating devices similar to swept panoramic receivers
• CPC Class Codes: G01R 27/32 in circuits having distributed constants , e.g. having very long conductors or involving high frequencies

Abstract

A measurement unit U100 measures an input signal to be measured by sweeping frequencies in a measurement range having a predetermined frequency band so as to obtain waveform data to be developed on the frequency axis such as spectrum data in, e.g., a spectrum analyzer. The waveform data obtained by the measurement of the measurement unit U100 is displayed by a display device 500 via a display data processor U20 included in a control unit U200 to be developed on the frequency axis of the display device, i.e., in correspondence with the measurement frequencies. The control unit U200 includes a measurement controller U30 for controlling the measurement unit U100 so as to display waveform data obtained by enlarging or reducing waveform data, before a measurement frequency condition is changed, at a predetermined magnification to have a predetermined point on the frequency axis as the center on the basis of a change in measurement frequency condition set by a condition setting unit U900, and an enlargement display/stable display processor U40 for controlling the display data processor U20. The enlargement display/stable display processor U40 realizes high-definition waveform observation, and has a function of controlling the display device U500 as the control unit U200.

Claims

1. A waveform display apparatus of frequency sweep type, comprising:

a measurement unit for measuring a signal to be measured by sweeping a frequency under a predetermined measurement frequency condition so as to obtain waveform data corresponding to the frequency;

a display device for displaying the waveform data obtained by said measurement unit as developed on a frequency axis thereof;

first parameter setting means for setting a first measurement frequency range, and setting a first scale factor for displaying waveform data in the first measurement frequency range on said display device;

a first parameter memory for storing parameters set by said first parameter setting means;

reference parameter setting means for setting a desired frequency on the frequency axis on said display device as a reference position, said desired frequency being within said first measurement frequency range corresponding to the waveform data displayed with the first scale factor;

second parameter setting means for setting a second measurement frequency range, and setting a second scale factor enlarging the first scale factor, for a portion of the frequency axis which includes said desired frequency and set by the reference parameter setting means for displaying waveform data in the second measurement frequency range on said display device;

a second parameter memory for storing parameters set by said second parameter setting means; and

control means for controlling the first and second measurement frequency ranges in said measurement unit, and controlling a display position in said display device so as to cause a coincidence between said desired frequency at the reference position set by said reference parameter setting means and one frequency in the second frequency range at the reference position, and to permit to display the waveform data in the second frequency range according to the second scale factor.

2. A waveform display apparatus according to claim 1, wherein said control means includes a feature point detection unit for detecting a frequency at a feature point of the waveform data obtained by said measurement unit, and a frequency deviation calculation unit for detecting a difference between the frequency at the feature point detected by said feature point detection unit, and a frequency corresponding to the reference position set by said reference parameter setting means, and changes the reference position and the measurement frequency range information in said second parameter memory according to the difference information from said frequency deviation calculation unit, so that the frequency corresponding to the reference position coincides with the frequency at the feature point on one point on the frequency axis on said display device, thereby controlling the first and second measurement frequency ranges in said measurement unit.

3. A waveform display apparatus according to claim 2, wherein said feature point detection unit detects a frequency at the feature point of the waveform data in the second measurement frequency range.

4. A waveform display apparatus according to claim 2, wherein said control means includes a feature point detection unit for detecting a frequency at a feature point of the waveform data obtained by said measurement unit, and a frequency deviation calculation unit for detecting a difference between the frequency at the feature point detected by said feature point detection unit, and a frequency corresponding to the reference position set by said reference parameter setting means, and changes the measurement frequency range information in said first and second parameters according to the difference information from said frequency deviation calculation unit, so that a position of the feature point on the frequency axis coincides with the reference position, thereby controlling the first and second measurement frequency ranges in said measurement unit, and said feature point detection unit detects a frequency at the feature point of the waveform data in the second measurement frequency range.

5. A waveform display apparatus according to claim 2, wherein said second parameter setting means includes means for setting a condition representing a zone on the frequency axis on said display device, a frequency range corresponding to a portion inside the zone coinciding with the second frequency range, said reference parameter setting means includes means for setting a condition representing the zone, a predetermined position in the zone coinciding with the reference position, and said feature point detection unit detects a frequency at the feature point of the waveform data in the second measurement frequency range.

6. A waveform display apparatus according to claim 2, wherein said control means includes a feature point detection unit for detecting a frequency at a feature point of the waveform data obtained by said measurement unit, and a frequency deviation calculation unit for detecting a difference between the frequency at the feature point detected by said feature point detection unit, and a frequency corresponding to the reference position set by said reference parameter setting means, and changes the measurement frequency range information in said second parameter according to the difference information from said frequency deviation calculation unit, so that the frequency corresponding to the reference position coincides with the frequency at the feature point on one point on the frequency axis on said display device, thereby controlling the first and second measurement frequency ranges in said measurement unit, said second parameter setting means includes means for setting a condition representing a zone on the frequency axis on said display device, a frequency range corresponding to a portion inside the zone coinciding with the second frequency range, said reference parameter setting means includes means for setting a condition representing the zone, a predetermined position in the zone coinciding with the reference position, and said feature point detection unit detects a frequency at the feature point of the waveform data in the second measurement frequency range.

7. A waveform display apparatus according to claim 2, wherein said control means includes a feature point detection unit for detecting a frequency at a feature point of the waveform data obtained by said measurement unit, and a frequency deviation calculation unit for detecting a difference between the frequency at the feature point detected by said feature point detection unit, and a frequency corresponding to the reference position set by said reference parameter setting means, and changes the measurement frequency range information in said second parameter according to the difference information from said frequency deviation calculation unit, so that a position of the feature point on the frequency axis coincides with the reference position, thereby controlling the first and second measurement frequency ranges in said measurement unit, said second parameter setting means includes means for setting a condition representing a zone on the frequency axis on said display device, a frequency range corresponding to a portion inside the zone coinciding with the second frequency range, said reference parameter setting means includes means for setting a condition representing the zone, a predetermined position in the zone coinciding with the reference position, and said feature point detection unit detects a frequency at the feature point of the waveform data in the second measurement frequency range.

8. A waveform display apparatus according to claim 1, wherein said control means includes a feature point detection unit for detecting a frequency at a feature point of the waveform data obtained said measurement unit, and a frequency deviation calculation unit for detecting a difference between the frequency at the feature point detected by said feature point detection unit, and a frequency corresponding to the reference position set by said reference parameter setting means, and changes the measurement frequency range information in said first and second parameter memories according to the difference information from said frequency deviation calculation unit, so that a position of the feature point on the frequency axis coincides with the reference position, thereby controlling the first and second measurement frequency ranges in said measurement unit.

9. A waveform display apparatus according to claim 1, wherein said second parameter setting means includes means for setting a condition representing a zone on the frequency axis on said display device, a frequency range corresponding to a portion inside the zone coinciding with the second frequency range, and said reference parameter setting means includes means for setting a condition representing the zone, a predetermined position in the zone coinciding with the reference position.

10. A waveform display apparatus according to claim 1, wherein said control means includes a feature point detection unit for detecting a frequency at a feature point of the waveform data obtained by said measurement unit, and a frequency deviation calculation unit for detecting a difference between the frequency at the feature point detected by said feature point detection unit, and a frequency corresponding to the reference position set by said reference parameter setting means, and changes the measurement frequency range information in said second parameter according to the difference information from said frequency deviation calculation unit, so that the frequency corresponding to the reference position coincides with the frequency at the feature point on one point on the frequency axis on said display device, thereby controlling the first and second measurement frequency ranges in said measurement unit, said second parameter setting means includes means for setting a condition representing a zone on the frequency axis on said display device, a frequency range corresponding to a portion inside the zone coinciding with the second frequency range, and said reference parameter setting means includes means for setting a condition representing the zone, a predetermined position in the zone coinciding with the reference position.

11. A waveform display apparatus according to claim 1, wherein said control means includes a feature point detection unit for detecting a frequency at a feature point of the waveform data obtained by said measurement unit, and a frequency deviation calculation unit for detecting a difference between the frequency at the feature point detected by said feature point detection unit, and a frequency corresponding to the reference position set by said reference parameter setting means, and changes the measurement frequency range information in said first and second parameters according to the difference information from said frequency deviation calculation unit, so that a position of the feature point on the frequency axis coincides with the reference position, thereby controlling the first and second measurement frequency ranges in said measurement unit, said second parameter setting means includes means for setting a condition representing a zone on the frequency axis on said display device, a frequency range corresponding to a portion inside the zone coinciding with the second frequency range, and said reference parameter setting means includes means for setting a condition representing the zone, a predetermined position in the zone coinciding with the reference position.