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4S1: Difference between revisions
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Each channel has a trigger pickoff, a [[delay line]], and a sampler. | Each channel has a trigger pickoff, a [[delay line]], and a sampler. | ||
Specified rise time is 350ps. | Specified rise time is 350ps. | ||
The sampling pulses for each channel are generated by a step recovery diode | The sampling pulses for each channel are generated by a step recovery diode. | ||
== Sampling Bridge == | |||
The sampling pulses are fed to a sampling bridge made of four [[sampling diodes|GaAs diodes]]. | |||
These diodes are fragile and exact replacements are hard to find. | These diodes are fragile and exact replacements are hard to find. | ||
People have improvised replacements using modern integrated Schottky | People have improvised replacements using modern integrated Schottky | ||
diodes such as those in HP/Agilent's HSMS-28x series. | diodes such as those in HP/Agilent's HSMS-28x series. | ||
== Dual-trace and X-Y Modes == | |||
The 4S1 has a dual-trace mode, where the A waveform and the B waveform | The 4S1 has a dual-trace mode, where the A waveform and the B waveform | ||
are both displayed in the time domain at the same time with a single | are both displayed in the time domain at the same time with a single | ||
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through [[Connectors#GR-874|GR-874 connectors]] on the front panel. | through [[Connectors#GR-874|GR-874 connectors]] on the front panel. | ||
== Trigger Amplifier == | |||
The 4S1 uses an unusual trigger amplifier with two trigger signal paths. One path is for low frequencies, the other for high frequencies. | The 4S1 uses an unusual trigger amplifier with two trigger signal paths. One path is for low frequencies, the other for high frequencies. | ||
(A similar approach was also used in the main vertical signal path of the [[7A29]] several years later.) | (A similar approach was also used in the main vertical signal path of the [[7A29]] several years later.) | ||
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to amplify the entire frequency range. | to amplify the entire frequency range. | ||
== Comparison with S1 Sampling Heads ==. | |||
The sampler board in the 4S1 is roughly equivalent to a pair of [[S1]] sampling heads. | The sampler board in the 4S1 is roughly equivalent to a pair of [[S1]] sampling heads. | ||
A short piece of RG/174 coax connects the 661 timing pulse coaxial connector to the | A short piece of RG/174 coax connects the 661 timing pulse coaxial connector to the | ||