NETWORK TIME DOMAIN MEASUREMENT SYSTEM

• US 3,812,423 A
• Filed: 07/16/1973
• Issued: 05/21/1974
• Est. Priority Date: 07/16/1973
• Status: Expired due to Term

• Current Assignee: Harry M. Cronson, Peter G. Mitchell
• Original Assignee: Harry M. Cronson, Peter G. Mitchell
• Inventors: Cronson, Harry M., Mitchell, Peter G.
• Primary Examiner(s): Krawczewicz, Stanley T.
• Application Number:
  US05/379,283
• Time in Patent Office: 309 Days
• Field of Search: 324/58.5A,58.5B
• US Class Current: 324/638
• CPC Class Codes: G01R 27/32 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 exposed to an incident base band impulse of electromagnetic energy in a transmission line is sampled by a compensation 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 characteristics of the network.

Claims

1. Apparatus including transmission line means for measuring the high frequency characteristics of a high frequency network under test comprising:

impulse wave generator means exciting said transmission line means for generating in the presence of said network under test corresponding forward and backward scattered waves, signal divider means having first and second port means for connection in series relation between said impulse wave generator means and said network under test, said signal divider means having third port means, wave sampling head means having first, second, third and fourth port means, and switch means having first, second, and third states, said switch means when in said first state being adapted to couple said signal divider means third port means to first matched load means and said network under test to said wave sampling head means first port means.

2. Apparatus as described in claim 1 wherein said switch means, when in said second state, is adapted to couple said signal divider third port means to said sampling head means second port means and said network under test to second matched load means.

3. Apparatus as described in claim 2 wherein said switch means, when in said third state, is adapted to couple said signal divider third port means to said first matched load means and said network under test to said second matched load means.

4. Apparatus as described in claim 3 including step attenuator means coupled in series between said impulse wave generator means and said signal divider means first port means.

5. Apparatus as described in claim 4 wherein said wave sampling head means third port means is coupled to said impulse wave generator means.

6. Apparatus as described in claim 5 wherein said sampling head means fourth port means is coupled to third matched load means.

7. Apparatus as described in claim 6 further including:

wave sample-and-hold means responsive to said wave sampling head means for holding representations of said impulse wave, said forward scattered wave, and said backward scattered wave, general purpose computing means responsive to said wave sample-and-hold means adapted to be programmed to compute said high frequency characteristics in response to said held wave representations, and display means responsive to said computing means for displaying said high frequency characteristics when computed.

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

digitizing said held wave representations of said impulse wave, of said forward scattered wave, and of said backward scattered wave, performing discrete Fourier transforms on said representations, and computing from said Fourier transforms the respective reflection and transmission scattering coefficients of said network.

9. Apparatus as described in claim 6 wherein the transmission propagation times between said impulse wave generator means and said step attenuator means, between said step attenuator means and said signal divider means, between said signal divider means and the location of said network under test, between said location of said network under test and said sampling head means first port means, between said signal divider means third port means and said sampling head means second port means, and between said impulse generator means and said sampling head means third port meaNs are substantially in the ratios of 2:

2;

1;

3;

2;

8.