Non-contact type wave signal observation apparatus

• US 5,656,932 A
• Filed: 01/12/1995
• Issued: 08/12/1997
• Est. Priority Date: 01/12/1994
• Status: Expired due to Fees

• Current Assignee: Advantest Corporation
• Original Assignee: Advantest Corporation
• Inventors: Kitayoshi, Hitoshi
• Primary Examiner(s): Wieder, Kenneth A.
• Assistant Examiner(s): BROWN, GLENN WARNER
• Application Number:
  US08/371,885
• Time in Patent Office: 943 Days
• Field of Search: 324/612, 324/615, 324/617, 324/618, 324/629, 324/630, 324/631, 324/637, 324/76.12, 324/76.19, 324/76.21, 324/76.24, 324/76.26, 324/76.78, 359/9
• US Class Current: 324/615
• CPC Class Codes: G01R 29/08 Measuring electromagnetic field characteristics
• CPC Class Codes: G01R 29/0892 Details related to signal analysis or treatment; presenting results, e.g. displays; measuring specific signal features other than field strength, e.g. polarisation, field modes, phase, envelope, maximum value
• CPC Class Codes: G01R 31/312 by capacitive methods
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: G01S 15/89 for mapping or imaging
• CPC Class Codes: G01S 7/02 of systems according to group G01S13/00
• CPC Class Codes: G01S 7/024 using polarisation effects in waveguides H01P1/165; for aerials H01Q, e.g. H01Q15/22, H01Q15/24, H01Q19/195
• CPC Class Codes: G01S 7/062 in which different colours are used
• CPC Class Codes: G01S 7/068 with data-rate converters preceding the display, e.g. flicker free display, constant brightness display G01S7/298 takes precedence
• CPC Class Codes: G01S 7/20 Stereoscopic displays; Three-dimensional displays; Pseudo-three-dimensional displays
• CPC Class Codes: G01S 7/2955 Means for determining the position of the radar coordinate system for evaluating the position data of the target in another coordinate system G01S7/24 takes precedence; sighting devices adapted for indirect laying of fire F41G3/16; inertial navigation G01C21/16

Abstract

A non-contact type wave signal observation apparatus measures transfer functions of a distributed constant network. A signal is input from a network analyzer to the network to be measured. Electromagnetic waves radiated from the network are received at each observation point on an observation plane arranged in a manner facing the network. The received signals are input to the network analyzer. The transfer functions between an input terminal of the network and each observation point are measured by the network analyzer. The measured transfer functions are converted by an inverse-Fresnel transformer and are stored in memories. The stored data is specified by a control unit and is displayed on a display unit. The stored data can be converted by an inverse-Fourier transformer and is displayed on the display unit as waveforms. Further aspect of the apparatus is, by a non-contact method, to measure signals of a distributed constant network, to determine states of electromagnetic wave in the space, to decrease the amount of calculations in a hologram reconstruction process, and to display a complex three dimensional illustration for a holographic radar.

Claims

1. A non-contact type transfer function measurement apparatus which provides an input signal to an input terminal of a distributed constant network under observation, comprising:

scanning-antenna receiving means for receiving electromagnetic waves radiated from said network at a number of observation points on an electromagnetic wave observation plane facing said network;

transfer function measuring means for measuring transfer functions between said input terminal of said network and said observation points;

transfer function conversion means for converting said transfer functions between said input terminal and said observation points of said network at each observation frequency of said input signal using an inverse-Fresnel transform process or Fourier transform process;

display means for displaying said converted transfer functions as frequency responses in said network.

2. A non-contact type transfer function measurement apparatus according to claim 1, wherein said display means displays a physical shape of said network, said display means including means for displaying said converted transfer function at said observation frequency in a two dimensional form and means for displaying frequency characteristics of location specified in said two dimensional form as a frequency response.

3. A non-contact type transfer function measurement apparatus according to claim 2, wherein said display means displays said physical shape and said converted transfer function in an overlay fashion.

4. A non-contact type transfer function measurement apparatus according to claim 1 further comprises characteristic compensating means for compensating a frequency characteristic of said transfer function measuring means.

5. A non-contact type transfer function measurement apparatus according to claim 1 further comprises domain converting means for converting frequency responses to time-domain responses using the inverse-Fourier transform, and wherein said display means displays said time-domain responses.

6. A non-contact type transfer function measurement apparatus according to claim 1 wherein said scanning-antenna receiving means is composed of an array antenna on said observation plane, and received signals of said array antenna are output by scanning said array antenna.

7. A non-contact type transfer function measurement apparatus according to claim 1 wherein said scanning-antenna receiving means is composed of an antenna which is moved to specified positions on said observation plane, and received signals of said antenna are output at said specified positions.

8. A non-contact type signal observation apparatus which observes signals at a number of observation points on an electromagnetic wave observation plane which faces a distributed constant network under observation, comprising:

scanning-antenna receiving means for receiving a repetition signal from said network;

means for generating a pulse signal synchronized with said repetition signal;

complex voltage converting means for converting said received signal to complex voltages based on the phase of said pulse signal at each observation frequency of said received signal;

means for converting said complex voltages to image data using an inverse-Fresnel transform process or a Fourier transform process;

display means for displaying said image data as spectra or waveforms.

9. A non-contact type signal observation apparatus according to claim 8, further comprises characteristic compensating means for compensating a frequency characteristic of said image data using data of radiation frequency characteristics of radiation points of said network and a frequency characteristic of said observation apparatus.

10. A non-contact type signal observation apparatus according to claim 8 wherein said complex voltage converting means is composed of means for filtering a frequency component of said observation frequency from both said received signal and said pulse signal, means for converting both filtered signals to low frequency signals, and means for converting transformed results of said received signal to signals which are referred to the phase of transformed results of said pulse signal.

11. A non-contact type signal observation apparatus according to claim 8 wherein said complex voltage converting means is composed of means for converting said received signal to low frequency signals by using a local signal generated by a local oscillator and a quadrature local signal which is produced by said local signal and is phase-shifted by 90 degree, means for converting said low frequency signal using the complex Fourier transform, means for converting said pulse signal to low frequency signals, means for converting both of said low frequency signals using the discrete Fourier transform, and means for performing an interference operation for transformed results of said received signal with respect to transformed results of said pulse signals.

12. A non-contact signal observation apparatus according to claim 11 wherein said repetition signal receiving means is composed of a reference timing antenna which receives electromagnetic waves from said network.

13. A non-contact type signal observation apparatus according to claim 8 wherein said scanning-antenna receiving means is composed of an antenna which is moved to specified positions on said observation plane, and received signals of said antenna are output at said specified positions.

14. A non-contact type signal observation apparatus according to claim 8 wherein said scanning-antenna receiving means is composed of an array antenna on said observation plane, and received signals of said array antenna are output by scanning said array antenna.

15. A non-contact signal observation apparatus according to claim 14, wherein said repetition signal receiving means is composed of a specific antenna element of said array antenna.

16. A spatial electromagnetic wave analysis apparatus which receives spatial electromagnetic waves at a number of observation points of an electromagnetic wave observation plane, and analyzes states of electromagnetic waves in a space, comprising:

scanning-antenna receiving means for receiving electromagnetic waves at said observation points by an antenna-element pair with mutually orthogonal 8-figured beam patterns;

complex signal converting means for converting received signals of said antenna-element pair to complex signals respectively;

reference signal receiving means for receiving a reference signal in said electromagnetic waves which is used as a reference phase for said received signals;

means for converting said reference signal to a reference complex signal;

means for calculating interference data of orthogonal polarized wave components of said received signals by dividing said complex signal by said reference complex signal;

means for calculating holograms using hologram reconstruction calculations of said interference data over said observation plane;

means for calculating polarized wave vectors which include results of said hologram calculations in vertical and horizontal components of elliptically polarized waves, at said observation points in said space;

display means for displaying parameters of said polarized wave vectors at said observation points.

17. A spatial electromagnetic wave analysis apparatus according to claim 16 wherein said reference receiving means is a fixed antenna.

18. A spatial electromagnetic wave analysis apparatus according to claim 16 wherein said complex signal converting means is composed of means for converting a frequency of said received signal to an IF signal of an intermediate frequency and means for converting said IF signal to Fourier spectrum using discrete Fourier transform process.

19. A spatial electromagnetic wave analysis apparatus according to claim 16 wherein said display means displays brightness modulated images according to intensity of said polarized wave vectors and hue modulated images according to other parameters of said polarized wave vectors at said reconstructed analysis points.

20. A spatial electromagnetic wave analysis apparatus according to claim 16 wherein said scanning-antenna receiving means is composed of an array antenna of said antenna-element pair on said observation plane, and received signals of said array antenna are output by scanning said array antenna.

21. A spatial electromagnetic wave analysis apparatus according to claim 16 wherein said scanning-antenna receiving means is composed of a scanning antenna of said antenna-element pair which is moved to specified positions on said observation plane, and received signals of said scanning antenna are output at said specified positions.

22. A holographic radar comprising:

means for radiating electromagnetic waves generated from a high frequency signal modulated by a pulse signal toward an object in a space;

scanning-antenna receiving means for receiving reflected waves from said object at a number of observation points on a hologram observation plane and for outputting received signals;

means for quadrature-detecting said received signals using said high frequency signal;

means for sampling said quadrature-detected signals by a sampling pulse signal synchronized with said pulse signal;

means for performing hologram reconstruction calculations on said sampled signal with respect to each of said observation points of said hologram observation plane;

variable delay means for delaying said sampling pulse signal by a delay value before supplying to said sampling means;

display means for displaying results of said hologram reconstruction calculations relative to said delay value in a three dimension form.

23. A holographic radar according to claim 22 wherein said scanning-antenna receiving means is composed of a scanning antenna which is moved to specified positions on said observation plane, and received signals of said scanning antenna are output at said specified positions.

24. A holographic radar according to claim 22 which further comprises means for judging whether said received signals are available at the advent of said sampling pulse signal from said variable delay means, and means for obtaining said received signals at all of said observation points only when said judging means determines that said received signals are available in synchronism with said sampling pulse signal.

25. A holographic radar according to claim 22 wherein said scanning-antenna receiving means is composed of an array antenna on said observation plane, and received signals of said array antenna are output by scanning said array antenna.

26. A holographic radar comprising:

means for radiating electromagnetic waves generated from a high frequency signal modulated by a pulse signal toward an object in a space;

scanning-antenna receiving means for receiving reflected waves from said object at a number of observation points on a hologram observation plane and for outputting received signals;

means for converting said received signals to low frequency signals;

means for sampling said low frequency signals in synchronism with said pulse signal by a sampling pulse signal having a frequency more than two times higher than that of said low frequency signals;

means for converting a fixed number of data produced by said sampling means which are delayed by a specified delay value through a discrete Fourier transform process;

means for performing hologram reconstruction calculations on results of said discrete Fourier transform process with respect to each of said observation points on said hologram observation plane;

display means for displaying results of said hologram reconstruction calculations relative to said delay value in a three dimension form.

27. A complex wave interference information display apparatus comprising:

interference data observing means for observing complex two-dimensional wave interference data;

means for performing hologram reconstruction calculations of said interference data;

means for converting coordinates of results of said hologram reconstruction calculations from orthogonal to polar coordinates;

means for converting phase information in polar coordinates data obtained by said converting means to hue information;

means for modulating said hue information by amplitude information in said polar coordinates data;

display means for displaying said modulated data as a two-dimensional color image.

28. A complex wave interference information display apparatus according to claim 27 further includes a holographic radar wherein said interference data observing means receives waves on an observation plane of said holographic radar and converts received signals to complex signals.

29. A complex wave interference information display apparatus according to claim 28 wherein said interference data observing means for receiving said two-dimensional interference waves in a three-dimensional space at a number of observation points on said observation plane and converts received signals to complex signals.

30. A complex wave interference information display apparatus according to claim 29 wherein said two-dimensional interference waves at said observation points are received by an antenna-element pair with mutually orthogonal 8-figured beam patterns, and wherein holograms are acquired from said complex two-dimensional interference data received from said antenna-element pair, and wherein polarized wave vectors are acquired which have said holograms as vertical and horizontal components, and wherein either of an axial ratio, a rotating angle or an inclination at the direction of propagation of the polarized wave vectors is used as said phase information.