"Electrical Wave Analysis", Siegfried Hansen
U.S. Patent April 21, 1942, 2,280,524
Basic sampling oscillography patent. Figures are identical to Norgaard's patent.

"Oscillograph Apparatus", Donald E. Norgaard
U.S. Patent Nov 1, 1940, 2,280,531
The first modern oscillography patent. Clearly shows a sampled waveform with a linear sweep.

"Circuit for continuously corrected storage", A. C. Stocker
U.S. Patent May 20, 1953, 2,781,445
An early sample-and-hold with "correction", meaning a feedback loop. It does include a four diode switch (bridge).

"Electronic switching circuit", E. Durbin
U.S. Patent Sep 30, 1954, 2,817,757
Improvements to the four diode switch (bridge)

"Sweep Circuit", A. R. Carlson
U.S. Patent May 19, 1960, 3,010,071
Specific sweep circuit for sampling, including synchronized horizontal ramp with sampling pulse as well as magnification.

"Plural series gate sampling circuit using positive feedback", K. B. Magleby, V. E. Van Duzer
U.S. Patent Aug 10, 1959, 3,011,129
This very important patent establishes the use of positive feedback to compensate for low sampling efficiency.

"Circuits for sampling oscilloscopes", G. B. B. Chaplin, A. R. Owens, C. J. N. Caudy
U.S. Patent Nov 28, 1958, 3,069,559
Uses avalanche transistors to create trigger pulses for the sampling gate.

"Pulse sampling circuit emplying diode pair conected to tunnel circuit", W. S. Mortley, S. F. Clarke, S. N. Radcliffe
U.S. Patent May 9, 1962, 3,143,732

"Direct Sampling Apparatus", J. V. Rogers
U.S. Patent Feb 18, 1963, 3,229,212
Sampling probe using 4 diode switch.

"Signal Sampling Circuit including a signal conductor disposed in the", K. B. Magleby, W. M. Grove
U.S. Patent Mar 18, 1963, 3,241,076
This two diode switch uses a shorted transmission line to reflect the conduction pulse. Used in the 1415 TDR unit and 1432 sampler.

"Oscilloscope sweep circuits", A. R. Carlson
U.S. Patent Aug 13, 1963, 3,244,989
Slow sampling sweep rates cause problems with the low density of sampling points; this invention uses a staircase generator in sync with the sweep ramp.

"Rachet Memory Circuit and Sampling System Employing Such Circuit", J. R. Kobbe, C. H. Moulton, J. V. Rogers, C. N. Winningstad
U.S. Patent May 7,1962, 3,248,655
Improves the idea of feedback from the output of the track and hold to the sampling gate to reduce the need to charge the capacitor to full value.

"Two diode balanced signal sampling apparatus", W. M. Grove
U.S. Patent Aug 23,1975, 3,278,763
The famous 1430A sampler. Uses a biconical "cavity" to spread the sampling pulse. This is a derivative of the 3,241,076 patent.

"Synchronized Random Sampling Oscilloscope", T. Hornak
U.S. Patent Dec 17,1965, 3,456,189
Fundamental random sampling patent inspired by Frye and Nahman.

"Analysis of nonrepetitive pulse waveforms by selection and storage of pulse increments", Q. A. Kerns
U.S. Patent Nov 29,1966, 3,484,689
Uses a series of delay lines to sample fast transient signals.

"Sampling Circuit", P.E. Stuckert
U.S. Patent Jun 30,1969, 3,596,191
Uses two 4 diode switches in tandem (one on and one off) to capture signals; the key is that the transmission lines controlling the switching pulses are of unequal length.

"Oscilloscope signal sampling system", G.J. Frye
U.S. Patent May 26,1969, 3,611,003

"Sampling system", G.J. Frye
U.S. Patent Jul 12,1968, 3,629,731

"Sequential Sampling System", B. J. Elliot, J.L. Staples
U.S. Patent Jul 13,1970, 3,704,416
Use two sampling 'scopes in tandem to reduce drift and jitter.

"Time and sequence determining circuit", G.J. Frye
U.S. Patent Apr 29,1971, 3,747,002

"Sampling Device", L.R. Lockwood
U.S. Patent Aug 23,1971, 3,760,283

"Microwave Sampling Device", M.A. Hreha
U.S. Patent , 3,768,025
Waveguide mounting of diodes with step recovery diode pulse generation

"Waveform Sampler", R.A. Lawton, J.R. Andrews
U.S. Patent Mar 25,1976, 4,030,840
Use two GaAs photoconductors in a transmission line and illuminate them with a laser.

"Stabilized high-efficiency sampling system", G.J. Frye
U.S. Patent Aug 19,1974, 4,069,447
Use of the feedback loop to control stability and efficiency of the sampling gate.

"High Speed Sampling Head", R. J. Bosselaers
U.S. Patent Feb 10, 1981, 4,399,413
Interestingly enough, this patent seems to predate the Tektronix travelling wave sampler patents.

"Travelling Wave Sampler", Agoston Agoston
U.S. Patent Mar 28, 1986, 4,647,795
Proposes the use of a simple DSP system: an A/D a small DSP and a D/A to compensate for blowby in sampling gates.

"Phase Detector", L.R. Lockwood
U.S. Patent Aug 30,1985, 4,654,600
Uses a shorted slotline to reflect pulses generated by the SRD and a coplanar waveguide.

"Sampling Bridge", A.J. Metz
U.S. Patent Apr 1,1985, 4,659,945
Various improvements on the 4 diode switch. A compensating bridge is added to increase strobe feedthrough but at the same time minimize blowby.

"Memory gate for error sampler", Agoston Agoston
U.S. Patent Apr 14,1985, 4,659,946
Memory gate is another way of describing a track-and-hold. This patent describes a circuit that tracks the input current so that the capacitor can be charged independently of the current value on the capacitor.

"Apparatus for Random Repetitive Sampling", L. Whiteside, T. K. Bohley
U.S. Patent Feb 21, 1986, 4,694,244
Uses a MM5437 PRN noise generator to create random delays as part of a timebase for a digital oscilloscope (of the 54000 family)

"Dual Channel Time Domain Reflectometer", A. Agoston, J. B. Rettig, S. P. Kavoekis, J. K. Carlson, A. K. Finkbeiner
U.S. Patent Apr 30, 1986, 4,755,742
A single Step Recovery Diode can control two sampling gates.

"Fast Transition, Flat pulse generator", A. Agoston, J. K. Carlson
U.S. Patent Jul. 1988, 4,758,736
A nice circuit that drives two outputs from a single SRD via a Schottky diode pair.

"Equivalent Time Pseudorandom Sampling System", A. Agoston
U.S. Patent May 1, 1986, 4,678,345
This early digital sampler patent describes a method of measuring the time interval between samples and generating a corrected sampling pulse.

"Programmable Sampling Time Base Circuit", A. Agoston
U.S. Patent Apr 30, 1986, 4,812,769
This digital time base uses a microprocessor to control a DAC which controls a VCO to produce a variable delay. The microprocessor also controls a time measurement section and the triggering.

"Travelling Wave Sampler", A. Agoston
U.S. Patent Mar. 1987, 4,647,795
This patent modifies the well known travelling wave sampler (used in the S-4 and S-6 samplers) to include a microcontroller that digitizes the output of the track and hold and digitally generates a bias for the gate.

"FISO sampling system\%A W. N. Buchele",
U.S. Patent May 23,1989, 4,833,445
FISO = Fast In, Slow Out. This uses a delay line with multiple gates.

"Monolithic Sampler", C-Y Su, T. Tan, W. J. Anklam
U.S. Patent Sep 11,1990, 4,956,568
A state of the art sampler using shock wave pulse generator and reflection damping.

"Method and apparatus for increasing the high frequency sensitivity response of a sampler frequency converter", M. I. Grace, P. M. Kapetanic, E. C. Liu
U.S. Patent Mar 13, 1990, 5,113,094
The use of a sampler in VNAs results in sin x/x distortion. By biasing the sampling diodes appropriately, the distortion can be corrected.

"Method and apparatus for probing and sampling an electrical signal", L.J. Dobos, A.J. Metz
U.S. Patent Oct 7,1991, 5,225,776
Newer probe with diode gate and differential amp.

"Equivalent Time Sampler Using an Oscillator", K. M. Ainsworth, D. G. Baker
U. S. Patent Jan 16, 1992, 5,260,670
A phase lock loop is used to control an oscillator that in turn controls the sampling gate.

"High speed transient sampler", T. E. McEwan
U.S. Patent Sep 8,1992, 5,471,162
Uses a meandering transmission line as a delay line with numerous sampling gates. The output of the gates is demultiplexed.

"Integrated coplanar strip nonlinear transmission line", R. A. Marsland, M. J. W. Rodwell, D. M. Bloom
U.S. Patent Jul 6, 1992, 5,256,996
How to integrate a GaAs nonlinear shockwave transmission line.

"Ultra-wideband receiver", T. E. McEwan
U.S. Patent Apr 12,1993, 5,345,471
How to use a sampling gate as part of a wideband receiver.

"Gallium Arsenide monolithically integrated sampling head using equivalent time sampling having a bandwidth of greater than 100 GHz", R. A. Marsland, M. J. W. Rodwell, D. M. Bloom
U.S. Patent Apr 16,1991, 5,378,939
Complete sampler including nonlinear transmission line pulse sharpener. 300 GHz bandwidth is claimed.

"Ultra-wideband directional sampler", T. E. McEwan
U.S. Patent Aug 3,1995, 5,517,198
In TDR, when the reflected pulse can return while the pulse is still be transmitted. This patent combines the functions of a directional coupler with a high speed sampler.

Last updated Mon Apr 27 15:08:53 EDT 1998

Created on Apr 27, 1998 at 15:07

Mark Kahrs, CAIP Center, P.O. Box 1390, Piscataway, NJ, 08855-1390
Phone: +1 732-445-6348, Fax: +1 732-445-4775

e-mail: kahrs@caip.rutgers.edu
home page:http://www.caip.rutgers.edu/~kahrs