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11A52: Difference between revisions
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The 11A52 uses custom Tektronix-made chips including the [[155-0076-00]] (M94 overload detector) and [[M377]] amplifier integrated circuit. | The 11A52 uses custom Tektronix-made chips including the [[155-0076-00]] (M94 overload detector) and [[M377]] amplifier integrated circuit. | ||
The signal output of | The signal output of each attenuator feeds a hybrid through a (blue) 50 ohm cable. The hybrid looks like packaged M377s found in other instruments. It contains a 50 ohm termination resistor, a diode bridge that protects the M377 from transients too fast for the input relay to react, and an [[M377]] amplifier IC. The input signal is connected to the + input of the [[M377]] amplifier. The cable lengths set a standard delay per plugin. | ||
The M377's − input is connected to the ACVS (Analog Control Voltage System) output. | The M377's − input is connected to the ACVS (Analog Control Voltage System) output located on a daughter board. | ||
The (differential) display outputs of the two M377 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 (differential) display outputs of the two M377 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. | ||
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See also the block diagram below. | See also the block diagram below. | ||
The 11A52 is very similar to the 11A32. There are a few differences. The difference in bandwidth (600 MHz vs 400 MHz) is due almost entirely to the difference in input attenuators. The 11A52 50 Ω | The 11A52 is very similar to the 11A32. There are a few differences. The difference in bandwidth (600 MHz vs 400 MHz) is due almost entirely to the difference in input attenuators. The 11A52 50 Ω attenuator is passive and contains no amplifier. Additionally the 11A52's M377 sees a 25 ohm source impedance (a terminated 50 ohm transmission line). The 11A32's M377 is driven by the 50 ohm output impedance of the [[M473]]. | ||
The [[11A32]] and [[11A34]] have only one transient response adjustment. This adjustment affects the high frequency response of all six of the M377's fixed gain settings. The 11A52 has the added luxury of a high frequency adjustment for each of the M377's six gain settings to optimize the response at each setting. These settings are manually set under computer control and stored in NVRAM. They need to be reset when the 11A52's NVRAM is replaced. The NVRAM's internal battery typically lasts 20 to 30 years. | The [[11A32]] and [[11A34]] have only one transient response adjustment per channel. This adjustment affects the high frequency response of all six of the M377's fixed gain settings (1 mV/div - 50 mV/ div). The 11A52 has the added luxury of a high frequency adjustment for each of the M377's six gain settings to optimize the response at each setting. These settings are manually set under computer control and stored in NVRAM. They need to be reset when the 11A52's NVRAM is replaced. The NVRAM's internal battery typically lasts 20 to 30 years. | ||
If you care to write down the twelve calibration constants while the NVRAM is still alive, you may simply enter them into the new NVRAM. If you do not write them down, you may observe the transient response and set the calibration constants via a personal computer. Instructions for this are found at [[11A-series plug-in NVRAM replacement]] | If you care to write down the 11A52's twelve calibration constants while the NVRAM is still alive, you may simply enter them into the new NVRAM. If you do not write them down, you may observe the transient response and set the calibration constants also via a personal computer. Instructions for this are found at [[11A-series plug-in NVRAM replacement]] | ||
===Digital=== | ===Digital=== | ||