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7912: Difference between revisions
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The Tektronix 7912 is a high-speed digitizer that takes one 7000-series vertical plug-in | The Tektronix 7912 is a high-speed digitizer that takes one 7000-series vertical plug-in | ||
and one 7000-series horizontal plug-in. There is a 7912AD which has | and one 7000-series horizontal plug-in. There is a 7912AD which has 500 MHz bandwidth | ||
and a 7912HB which | and a 7912HB which offers 750 MHz bandwidth. | ||
CRT-based digitizing [[scan converter]] tube | |||
that is not visible from the outside. The signal goes from | These instruments contain a special internal CRT-based digitizing [[scan converter]] tube | ||
the vertical plug-in to the vertical amplifier to the digitizing tube where it deflects | that is not visible from the outside. The signal goes from the vertical plug-in to the | ||
a beam of electrons. The electrons hit a small flat rectangular target inside the tube. | vertical amplifier to the digitizing tube where it deflects a beam of electrons. | ||
The electrons hit a small flat rectangular target inside the tube. | |||
This target is a solid state image sensor, conceptually similar to that in a digital camera. | This target is a solid state image sensor, conceptually similar to that in a digital camera. | ||
The trace is read from the target by electronics in the 7912AD, digitized, and stored in memory. | The trace is read from the target by electronics in the 7912AD, digitized, and stored in memory. | ||
The reading of the target is asynchronous from the sweep and therefore the tube can be considered | The reading of the target is asynchronous from the sweep and therefore the tube can be considered | ||
a form of scan converter. Three output methods are provided: NTSC-out, X-Y low-speed analog, and GPIB | a form of scan converter. Three output methods are provided: NTSC-out, X-Y low-speed analog, | ||
and a [[GPIB interface]] | |||
The resolution of the target is 512x512, giving 512 points in the time domain and 9-bit linear | The resolution of the target is 512x512, giving 512 points in the time domain and 9-bit linear | ||
quantization of the input voltage. Skipping the vertical amplifier, the 7912 can provide a | quantization of the input voltage. Skipping the vertical amplifier, the 7912 can provide a | ||
bandwidth of | bandwidth of 1 GHz with a sensitivity of 4V/Div. | ||
With aftermarket modifications to the electronics, 7912AD | |||
bandwidths have been extended above | With aftermarket modifications to the electronics, 7912AD bandwidths have been extended above | ||
in | 2 GHz in special cases. With a 7B92 sweeping the whole X-axis in 5 ns, and the 7912AD capturing | ||
512 samples in that sweep, the 7912AD performs the function of a 100 GSample/s ADC. | |||
They were expensive. | |||
The technology was designed at Tektronix in the 1970's and sold through the 1980's. They were expensive. | |||
The WP 2000 (067-0679-00) Digital Display Controller is an external module that interfaces with the 7912. | The WP 2000 (067-0679-00) Digital Display Controller is an external module that interfaces with the 7912. | ||
Plugin modules for the 7912 have a 'P' suffix, meaning Programmable. | Plugin modules for the 7912 have a 'P' suffix, meaning Programmable, e.g. [[7A16P]], [[7A29P]] and [[7B90P]]. | ||
==Specifications== | ==Specifications== | ||
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[[Category:7000 series digitizer mainframes]] | [[Category:7000 series digitizer mainframes]] | ||
[[Category:Specifications needed]] | [[Category:Specifications needed]] | ||
[[Category:GPIB interface]] | |||