Network time domain measurement system

• US 3,903,477 A
• Filed: 07/29/1974
• Issued: 09/02/1975
• Est. Priority Date: 07/29/1974
• Status: Expired due to Term

• Current Assignee: Harry M. Cronson, Peter G. Mitchell
• Original Assignee: Harry M. Cronson, Peter G. Mitchell
• Inventors: Mitchell, Peter G., Cronson, Harry M.
• Primary Examiner(s): Krawczewicz, Stanley T.
• Application Number:
  US05/492,553
• Time in Patent Office: 400 Days
• Field of Search: 324/58.5A,58.5B,58.5R,58A
• US Class Current: 324/642
• CPC Class Codes: G01R 27/04 in circuits having distributed constants , e.g. having very long conductors or involving high frequencies

Abstract

The forward and backward scattered energy of a high frequency network or composition of matter exposed to a composite electromagnetic energy wave is sampled by a compensated sampling system and the incident wave and reflected and transmitted response waves are employed in performing discrete Fourier transformations in a computation process yielding the complex electrical characteristics of the network or composition of matter.

Claims

1. Apparatus for measuring the high frequency electrical characteristics of a high frequency transmission line element under test by propagation of forward and backward scattered high frequency signals therethrough comprising:

step wave generator means, delay means responsive to said step wave generator means for producing a delayed step wave, first and second branching circuit means jointly responsive to said delay means, said first branching circuit means including harmonic wave generator means responsive to said delayed step wave, said second branching circuit means including differentiator circuit means responsive to said delayed step wave for producing a base band impulse signal, junction means coupling said first and second branching circuit means for forming a composite test signal, signal sampling means coupled between said junction means and said high frequency transmission line element when present for conducting said composite test signal through said high frequency transmission line element as a forward scattered high frequency signal, reflector means for reflecting said forward scattered high frequency signal through said transmission line element as a backward scattered high frequency signal, wave sample - and - hold means responsive to said signal sampling means for holding representations of said composite test signal, said forward scattered signal, and said backward scattered signal, general purpose computing means responsive to said wave sample and - hold means adapted to be programmed to compute said high frequency electrical characteristics in response to said held wave representations, and display means responsive to said computing means for displaying said high frequency characteristics when computed.

2. Apparatus as described in claim 1 wherein at least one of said first and second branching circuit means includes adjustable delay means.

3. Apparatus as described in claim 2 wherein at least one of said first and second branching circuit means includes attenuator means.

4. Apparatus as described in claim 1 wherein said sample - and -hold means is additionally responsive to said step wave generator means.

5. Apparatus as described in claim 1 wherein said harmonic wave generator means comprises harmonic generator diode means disposed within cavity resonator means.

6. Apparatus as described in claim 4 wherein said differentiator circuit means comprises capacitor means coupled in series between said delay means and said junction means and diode means coupled between said delay means and ground.

7. Apparatus as described in claim 4 wherein said general purpose computing means is adapted to be programmed for:

digitizing said held wave representations of said composite test signal, of said forward scattered signal, and of said backward scattered signal, performing discrete Fourier transformations on said representations, and computing from said Fourier transformations the respective high frequency electrical characteristics of said high frequency transmission line element.