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George Frye: Difference between revisions
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he developed the random sampling technique under a grant from the US National Security Agency. | he developed the random sampling technique under a grant from the US National Security Agency. | ||
George writes: “But then realized that a NSA project I worked on while going for my MSEE at KU showed the way to generate real time sampling pulses at very high frequencies. | George writes: | ||
<blockquote> | |||
“But then realized that a NSA project I worked on while going for my MSEE at KU showed the way to generate real time sampling pulses at very high frequencies. | |||
Just use a klystron. Velocity modulate the beam at the desired sampling frequency and then place a catch electrode at the point where the electrons combine in pulses at the modulating frequency. Klystrons usually place a cavity there to collect the amplified RF signal. | Just use a klystron. Velocity modulate the beam at the desired sampling frequency and then place a catch electrode at the point where the electrons combine in pulses at the modulating frequency. Klystrons usually place a cavity there to collect the amplified RF signal. | ||
That was the basis for the project I was assigned to. 60 years ago…” | That was the basis for the project I was assigned to. 60 years ago…” | ||
</blockquote> | |||
While still in Kansas City, he took a job at Bendix Corporation. | While still in Kansas City, he took a job at Bendix Corporation. That was work for the Department of Defense. | ||
That was work for the Department of Defense. | |||
In 1962, he joined [[Norm Winningstad]]'s sampling group at Tektronix. | In 1962, he joined [[Norm Winningstad]]'s sampling group at Tektronix. | ||
Their group was in a building on Barnes road. Later, they moved to the second floor of Building 50 on the Tektronix Campus. | Their group was in a building on Barnes road. Later, they moved to the second floor of Building 50 on the Tektronix Campus. | ||
George's first assignment at Tek was to build a test waveform generator for internal purposes. | George's first assignment at Tek was to build a test waveform generator for internal purposes. It didn't go into production. | ||
It didn't go into production. | |||
After Norm Winningstad left Tektronix in the mid-1960s, George Frye's manager was [[Al Zimmerman]]. | After Norm Winningstad left Tektronix in the mid-1960s, George Frye's manager was [[Al Zimmerman]]. | ||
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George Frye pondered how to build a very fast (low aperture time) sampler using the components Tek had at the time. | George Frye pondered how to build a very fast (low aperture time) sampler using the components Tek had at the time. | ||
He decided to leverage the very short turn-off time of Tek's Schottky diodes. | He decided to leverage the very short turn-off time of Tek's Schottky diodes. | ||
This led to the invention of the traveling wave sampling gate, US patent number 3629731. | This led to the invention of the traveling wave sampling gate, [[Patent US 3629731A|US patent number 3629731]]. | ||
In this new sampling gate design, | In this new sampling gate design, the aperture time is not a function of the length of the sampling strobe pulse. | ||
the aperture time is not a function of the length of the sampling strobe pulse. | Only the falling edge matters. Another way of viewing this is that conventional sampling heads depended on the | ||
Only the falling edge matters. | sampling pulse having a high second derivative, whereas the new design only required a high first derivative. | ||
Another way of viewing this is that conventional sampling heads | |||
depended on the sampling pulse having a high second derivative | |||
whereas the new design only required a high first derivative. | |||
This led to a significantly faster sampling head. | This led to a significantly faster sampling head. | ||
The first product using this new sampling gate design was the [[S-4]], which has a rise time of 25 picoseconds. | The first product using this new sampling gate design was the [[S-4]], which has a rise time of 25 picoseconds. | ||