US 4,818,931 A · Vector analyzer with display markers and linear transform capability

Abstract

A vector analyzer incorporates a set of five types of markers for the display, which facilitate the visual analysis of the magnitude, phase and time relationships of the I and Q components of the modulation states displayed. The five markers are: an I marker, a Q marker, a magnitude marker, a phase marker and a time marker. The I and Q markers indicate amplitude in the I and Q coordinates displayed on the X-Y displays. The magnitude marker indicates amplitude on the radial coordinate of the X-Y displays. The phase marker indicates relative phase on the angular coordinate of the X-Y displays. The time marker indicates the time coordinate on the displays, and controls the time instant displayed. The analyzer also incorporates a circuit for performing linear transforms on the I, Q, and time data which allows real time adjustment of the sampled signals and enables the signals to be displayed in a three dimensional projection mode. The linear transform can be used to correct the display for three common sources of error in vector modulated signals: amplitude imbalance, phase errors, and quadrature errors. After the display has been corrected, the correction factors are a measure of the errors in the input signal, or in the device demodulating the input signal.

Claims15

Dependent claims

Apparatus for use in the display and analysis of vector modulated signals, comprising:

input means for receiving an input signal including inphase and quadrature components;
sampling means for sampling the input signal to provide a sampled signal;
signal processing means coupled to the sampling means for generating an electronic representation of the input signal in response to the sampled signal;
display control means coupled to the signal processing means and responsive to operator control signals for providing display control signals;
display means coupled to the signal processing means and to the display control means, for providing a waveform display in response to the electronic representation of the sampled signals and to the display control signals;
operator controls coupled to the display control means and including means for providing operator control signals in response to operator manifestations for selecting and positioning a marker on the waveform display;
said operator control signals including marker control signals for causing the display means to display visual representations of vector magnitude markers, vector phase markers, and time markers at selected values of cartesian or polar coordinates on the waveform display.

4 more elements

Dependencies are inferred from the claim text.

Vector analyzer with display markers and linear transform capability

Life of this patent

Vector analyzer with display markers and linear transform capability

Life of this patent

Abstract

Claims15