page_title: Oscilloscope history
section_title: Tektronix
hierarchical_section_title: Oscilloscope history / Tektronix
caption_attribution_description: Tektronix 465 Oscilloscope. This is a dual-channel, 100 MHz bandwidth, analog oscilloscope.
context_page_description: The history of the oscilloscope reaches back to the first recordings of waveforms with a galvanometer coupled to a mechanical drawing system in the second decade of the 19th century. The modern day digital oscilloscope is a consequence of multiple generations of development of the oscillograph, cathode-ray tubes, analog oscilloscopes, and digital electronics.
context_section_description: Vollum and Murdock went on to found Tektronix, the first manufacturer of calibrated oscilloscopes (which included a graticule on the screen and produced plots with calibrated scales on the axes of the screen). Later developments by Tektronix included the development of multiple-trace oscilloscopes for comparing signals either by time-multiplexing (via chopping or trace alternation) or by the presence of multiple electron guns in the tube. In 1963, Tektronix introduced the Direct View Bistable Storage Tube (DVBST), which allowed observing single pulse waveforms rather than (as previously) only repeating wave forms. Using micro-channel plates, a variety of secondary-emission electron multiplier inside the CRT and behind the faceplate, the most advanced analog oscilloscopes (for example, the Tek 7104 mainframe) could display a visible trace (or allow the photography) of a single-shot event even when running at extremely fast sweep speeds. This oscilloscope went to 1 GHz.
  In vacuum-tube oscilloscopes made by Tektronix, the vertical amplifier's delay line was a long frame, L-shaped for space reasons, that carried several dozen discrete inductors and a corresponding number of low-capacitance adjustable ("trimmer") cylindrical capacitors. These oscilloscopes had plug-in vertical input channels. For adjusting the delay line capacitors, a high-pressure gas-filled mercury-wetted reed switch created extremely fast-rise pulses which went directly to the later stages of the vertical amplifier. With a fast sweep, any misadjustment created a dip or bump, and touching a capacitor made its local part of the waveform change. Adjusting the capacitor made its bump disappear. Eventually, a flat top resulted.
  Vacuum-tube output stages in early wideband oscilloscopes used radio transmitting tubes, but they consumed a lot of power. Picofarads of capacitance to ground limited bandwidth. A better design, called a distributed amplifier, used multiple tubes, but their inputs (control grids) were connected along a tapped L-C delay line, so the tubes' input capacitances became part of the delay line. As well, their outputs (plates/anodes) were likewise connected to another tapped delay line, its output feeding the deflection plates. (This amplifier was push-pull, so there were four delay lines, two for input, and two for output.)
caption: Type 465 Tektronix oscilloscope, a popular analog oscilloscope during the 1980s
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