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11A32: Difference between revisions
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==Internals== | ==Internals== | ||
===Analog=== | ===Analog=== | ||
Each input channel has a separate attenuator module containing an [[M474]] buffer amplifier. | Each input channel has a separate attenuator module containing passive 1 megohm attenuators, an AC coupling capacitor, a switch selecting the calibrator or signal input, and an [[M474]] buffer amplifier. The calibrator signal turned off inside the plugin when not in use. | ||
The | |||
The | The attenuator module output feeds the + input of the [[M377]] amplifier IC through a (blue) 50 ohm transmission line, one per input channel. The cable lengths set a standard delay per plugin. | ||
50 | |||
When not enabled, each M377 differential output is exactly zero by design. | The M377's - input is connected to the [[ACVS]] (Analog Control Voltage System) output. | ||
This fact is used during calibration by the plugin’s firmware to determine the mainframe’s imbalance and compensate for it during normal operation. | |||
The (differential) display outputs of the two amplifiers are hard-wired in parallel and drive the mainframe’s | |||
50 Ω per side input impedance. The same is true of the trigger outputs of the two amplifiers. | |||
The version of the M377 used in the 11A32 has a 100 Ω output impedance per side so that two of them in parallel | |||
create a source impedance of 50 Ω. | |||
Each M377 amplifier's nominal common-mode output voltage is zero whether enabled or not. When not enabled, each M377 | |||
differential output is exactly zero by design. This fact is used during calibration by the plugin’s firmware to | |||
determine the mainframe’s imbalance and compensate for it during normal operation. | |||
Each of the two channels has its own AUX output on dedicated pins of the plug-in interface connector: | |||
See also the block diagram below. | See also the block diagram below. | ||