Adaptive control electromagnetic signal analyzer

• US 5,117,377 A
• Filed: 10/05/1988
• Issued: 05/26/1992
• Est. Priority Date: 10/05/1988
• Status: Expired due to Fees

• Current Assignee: LCF Enterprises
• Original Assignee: LCF Enterprises
• Inventors: Finman, Paul F.
• Primary Examiner(s): Teska, Kevin J.
• Application Number:
  US07/253,965
• Time in Patent Office: 1,329 Days
• Field of Search: 364/148-152, 364/138, 364/514, 364/516, 364/572, 364/574, 364/578, 364/579, 364/481-484, 455/73, 455/79, 333/103, 333/109, 333/12, 333/81 R, 324/77 R, 324/77 B, 324/77 CS, 371/25.1
• US Class Current: 703/2
• CPC Class Codes: G01S 7/4004 of parts of a radar system

Abstract

An electromagnetic signal analyzer is disclosed which measures a signal from a test path and a signal from an adaptively controlled reference path. Specially biased semiconductor junctions function simultaneously as electromagnetic signal attenuators, electromagnetic signal detectors, and parametric frequency converters, thereby providing unique advantages for system calibration. Adaptive modeling of the measured response to control changes gives a measure of test path and signal characteristics and also provides a prediction of the measured response for both a change in the controls and a change of the input signal. A precision complex phasor modulator serves as an important building block for measurement and control of amplitude-modulated and frequency-hopping electromagnetic signals. Specific configurations of a disclosed generic electromagnetic signal analyzer include: (1) an instantaneous frequency and amplitude detector, (2) a vector Automatic Network Analyzer (ANA) for measurement of amplitude and phase characteristics of a device under test versus frequency, (3) a vector spectrum analyzer for measurement of the amplitude and phase versus frequency of an electromagnetic signal, and (4) an Adaptive Predictor Interference Canceler for Interference suppression in a fast frequency-hopping communication system.

Claims

1. An adaptive control electromagnetic signal analyzer system comprising:

a signal receiver means for receiving electromagnetic signals;

a reference signal transmission path including a multifunction controller/detector, said reference signal transmission path having a plurality of control inputs;

a test signal transmission path;

a power divider means for splitting signal power, said power divider means having an input port and two output ports, said output ports being connected to said reference path and said test path;

a reference signal source means for supplying a reference electromagnetic signal to said power divider input port, a portion of said reference electromagnetic signal being directionally coupled to an input of said electromagnetic signal receiver;

a means for modeling characteristics of said reference path and said test path;

a means for predicting the response to said system to changes in said reference signal source and said reference path controls based on said modeled characteristics of said reference path and said test path;

a system controller means for system measurement and control with measured inputs from said reference path and said signal receiver;

with calibration and system response prediction inputs from said predicting means; and

with control outputs to said reference signal source, said reference path, said receiver, said modeling means, and said predicting means; and

a signal summing means for combining signals from said reference path and said test path, said summing means having an output to said signal receiver.

2. The analyzer system of claim 1 wherein:

said modeling means includes a means for calculating said reference path control inputs required to maintain a desired system response for known changes in said reference signal source characteristics

and for minimizing predicted versus measured system response error by adapting model parameters based on recent previously measured and predicted system responses.

3. The analyzer system of claim 1 wherein said system control, modeling, and predicting means comprises a digital computer.

4. The analyzer system of claim 1 wherein said system control, modeling, and prediction means comprises analog circuitry.

5. The analyzer system of claim 1 wherein said test signal transmission path includes a multifunction controller/detector operatively connected to said system controller.

6. The analyzer system of claim 1 wherein said multifunction controller/detector circuit comprises:

a biased semiconductor junction having nonlinear current-versus-voltage dependence, nonlinear capacitance-versus-voltage dependence, and an electromagnetic signal impedance dependent on low-frequency bias current, said biased semiconductor junction operating simultaneously as an electromagnetic detector and a controlled impedance for electromagnetic signals; and

a semiconductor junction bias circuit having both a low-frequency signal path through said semiconductor junction and a high-frequency signal path through said semiconductor junction, with said low-frequency signal path isolated from said high-frequency signal path;

said bias circuit having a controllable current through said low-frequency signal path and having a semiconductor junction detected voltage output isolated from said high-frequency signal path;

said controllable current being independent of said detected voltage output, and said detected voltage output being dependent on a high-frequency electromagnetic signal through said semiconductor junction.

7. The analyzer system of claim 6 wherein said multifunction controller/detector further comprises temperature compensation means for compensating changes in operational characteristics of said controller/detectors due to changes in temperature.

8. The analyzer system of claim 7 wherein said temperature compensation means comprises:

a reference biased semiconductor junction circuit isolated from the electromagnetic signal appearing in said reference signal transmission path;

a test biased semiconductor junction circuit exposed to the electromagnetic signal appearing in said reference signal transmission path;

means for measuring a difference between the detected voltage from said test biased semiconductor junction and the voltage from said reference biased semiconductor junction with both junctions having virtually equal controllable bias currents and a common reference node.

9. An adaptive control electromagnetic signal analyzer system comprising:

a signal receiver means for receiving electromagnetic signals;

a reference signal transmission path including a multifunction controller/detector, said reference signal transmission path having a plurality of control inputs;

a test signal transmission path including a multifunction controller/detector, said test signal transmission path having a plurality of control inputs;

a reference signal source means for supplying a reference electromagnetic signal to input port of said reference signal transmission path, a portion of said reference electromagnetic signal being directionally coupled to an input of said electromagnetic signal receiver;

a test signal source means for supplying a test electromagnetic signal to an input port of said test signal transmission path;

a means for modeling characteristics of said reference path and said test path;

a means for predicting the response of said system to changes in said reference signal source and said reference path controls based on said modeled characteristics of said reference path and said test path;

a system controller means for system measurement and control with measured inputs from said reference path and said signal receiver;

with calibration and system response prediction inputs from said predicting means; and

with control outputs to said reference signal source, said reference path, said receiver, said modeling means, and said predicting means; and

a signal summing means for combining signals from said reference path and said test path, said summing means having an output to said signal receiver.

10. A method of calibrating an analyzer system that includes a signal receiver means for receiving electromagnetic signals, a reference signal transmission path including a multifunction controller/detector, said reference signal transmission path having a plurality of control inputs;

a test signal transmission path;

a power divider means for splitting signal power, said power divider means having input port and two output ports, said output ports being connected to said reference path and said test path;

a reference signal source means for supplying a reference electromagnetic signal to said power divider input port, a portion of said reference electromagnetic signal being directionally coupled to an input of said electromagnetic signal receiver;

a means for modeling characteristics of said reference path and said test path;

a means for predicting the response of said system to changes in said reference signal source and said reference path controls based on the modeled characteristics of said reference path and said test path;

a system controller means for system measurement and control with measured inputs from said reference path and said signal receiver;

with calibration and system response prediction inputs from said predicting means; and

with control outputs to said reference signal source, said reference path, said receiver, said modeling means, and said predicting means; and

a signal summing means for combining signals from said reference path and said test path, said summing means having an output to said signal receiver;

said method comprising;

(a) selecting a calibration standard for insertion as the test signal transmission path, or selecting a test signal with known characteristics;

(b) selecting a system state using known control outputs of said system controller;

(c) measuring the system response and recording the system response-versus-control table;

(d) returning to step (a) until completion of said system response-versus-control table; and

(e) calculating a system model based on said system response-versus-control table with a calibration model and function consisting of a linear combination of nonlinear functions.

11. The method of claim 10 further comprising the steps of:

(f) selecting a test signal transmission path of unknown electromagnetic propagation characteristics, or a test signal of unknown characteristics;

(g) selecting a system state with said system controller;

(h) measuring a system response and recording a system response-versus-control table;

(i) returning to step (g) until completion of said system response-versus-control table; and

(j) calculating electromagnetic propagation characteristics of calibration standard or test signal characteristics based on said system model.

12. A method for calibrating an analyzer system that includes:

a signal receiver means for receiving electromagnetic signals;

a reference signal transmission path including a multifunction controller/detector, said reference signal transmission path having a plurality of control inputs;

a test signal transmission path including a multifunction controller/detector, said test signal transmission path having a plurality of control inputs;

a reference signal source means for supplying a reference electromagnetic signal to input port of said reference signal transmission path, a portion of said reference electromagnetic signal being directionally coupled to an input of said electromagnetic signal receiver;

a test signal source means for supplying a test electromagnetic signal to an input port of said test signal transmission path;

a means for modeling characteristics of said reference path and said test path;

a means for predicting the response of said system to changes in said reference signal source and said reference path controls based on said modeled characteristics of said reference path and said test path;

a system controller means for system measurement and control with measured inputs from said reference path and said signal receiver;

with calibration and system response prediction inputs from said predicting means; and

with control outputs to said reference signal source, said reference path, said receiver, said modeling means, and said predicting means; and

a signal summing means for combining signals from said reference path and said test path, said summing means having an output to said signal receiver, said method comprising the steps of;

(a) selecting a calibration standard for insertion as the test signal transmission path, or selecting a test signal with known characteristics;

(b) selecting a system state using known control outputs of said system controller;

(c) measuring the system response and recording the system response-versus-control table;

(d) returning to step (a) until completion of said system response-versus-control table; and

(e) calculating a system model based on said system response-versus-control table with a calibration model and function consisting of a linear combination of nonlinear functions.

13. The method of claim 12 further comprising the steps of:

(f) selecting a test signal transmission path of unknown electromagnetic propagation characteristics, or a test signal of unknown characteristics;

(g) selecting a system state with said system controller;

(h) measuring a system response and recording a system response-versus-control table;

(i) returning to step (g) until completion of said system response-versus-control table; and

(j) calculating electromagnetic propagation characteristics of calibration standard or test signal characteristics based on said system model.

14. An adaptive control electromagnetic signal analyzer system comprising:

a signal receiver means for receiving electromagnetic signals;

a reference signal transmission path including a multifunction controller/detector, said reference signal transmission path having a plurality of control inputs;

a test signal transmission path;

a power divider means for splitting signal power, said power divider means having input port and two output ports, said output ports being connected to said reference path and said test path;

a reference signal source means for supplying a reference electromagnetic signal to said power divider input port, a portion of said electromagnetic signal being directionally coupled to an input of said electromagnetic signal receiver;

a means for modeling characteristics of said reference path and said test path;

a means for predicting the response of said system to changes in said reference signal source and said reference path controls based on the modeled characteristics of said reference path and said test path;

system controller means including inputs from said reference path and said signal receiver, and from said predicting means, and with outputs to said reference signal source, said reference path, said receiver, said modeling means and said predicting means; and

a signal summing means for combining signals from said reference path and said test path, said summing means having an output to said signal receiver.

15. An adaptive control electromagnetic signal analyzer system comprising:

a reference signal transmission path having an input port, an output port, at least one control port, and at least one monitor port and comprising means for adjusting phase and amplitude of an electromagnetic signal traveling said reference path;

a test signal transmission path having an input port, an output port, at least one control port, and at least one monitor port and comprising means for adjusting phase and amplitude of an electromagnetic signal traveling said test path, said test path being adapted to permit insertion of a device under test;

a signal supplying means having at least one control port and a plurality of output ports, two of said output ports being connected to the input ports of said test path and said reference path;

a receiver having three input ports, at least one control port, and at least one monitor port, said input ports being connected to the output ports of said test path, said reference path, and said signal supplying means, said receiver producing a response to said input signals at said receiver output port;

a system controller having a plurality of input and output ports connected to the control and monitor ports of said test path, said reference path, said signal supplying means, and said receiver for monitoring and controlling operations of said analyzer system, said system controller further comprising means for modeling the characteristics of said reference path and said test path.