Waveform display apparatus for easily realizing high-definition waveform observation

• US 5,434,954 A
• Filed: 11/27/1991
• Issued: 07/18/1995
• Est. Priority Date: 03/30/1990
• Status: Expired due to Fees

• Current Assignee: Anritsu Corporation
• Original Assignee: Anritsu Corporation
• Inventors: Kawauchi, Takehiko, Kamiyama, Katsuhiko, Iiyoshi, Katsuhisa, Katayama, Aiichi
• Primary Examiner(s): JANKUS, ALMIS R
• Application Number:
  US07/776,259
• Time in Patent Office: 1,329 Days
• Field of Search: 324/77, 364/481, 364/484-487, 395/140-143, 395/155, 395/161, 395/162, 395/133, 395/139
• 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
• CPC Class Codes: Y10S 715/97 Instrumentation and component modelling, e.g. interactive control panel

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 described later 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 as the gist of this invention, and substantially 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 which, when two out of four frequency parameters including a start frequency, a stop frequency, a center frequency, and a frequency span included in the predetermined measurement frequency condition are set to determine a measurement frequency range, can change one of the four frequency parameters;

reference parameter setting means for setting an arbitrary position on the frequency axis on said display device as a reference position; and

control means for, when said first parameter setting means changes one of the four frequency parameters, controlling to change the measurement frequency range in said measurement unit according to the changed parameter while maintaining a relationship in which a frequency at the position on said display device set by said reference parameter setting means is equal to a frequency before the one frequency parameter is changed.

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 controls the measurement frequency range in said measurement unit in accordance with the difference information from said frequency deviation calculation unit, so that the frequency at the reference position coincides with the frequency at the feature point.

3. A waveform display apparatus according to claim 2, wherein said reference parameter setting means includes means for setting a condition representing a zone on the frequency axis on said display device, a predetermined position in the zone being set as the reference position, and-said feature point detection unit includes means for detecting a frequency at the feature point corresponding to the waveform data in the zone.

4. A waveform display apparatus according to claim 1, wherein said reference parameter setting means includes means for setting a condition representing a zone on the frequency axis on said display device, a predetermined position in the zone being set as the reference position.