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7A22: Difference between revisions
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* [[Media:TB-9-6625-2132-35.pdf | TB 9-6625-2132-35 Calibration Procedure for AM-6881/U (7A13) and AM-6786/U (7A22)]] (PDF, 2M) | * [[Media:TB-9-6625-2132-35.pdf | TB 9-6625-2132-35 Calibration Procedure for AM-6881/U (7A13) and AM-6786/U (7A22)]] (PDF, 2M) | ||
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The '''Tektronix 7A22''' is a single channel differential vertical amplifier for the [[7000-series scopes|7000 series mainframes]], produced from about 1969 to 1991. Specifications and controls are similar to the [[26A2]] and the [[3A9]] from the 560 series but without current probe input or front panel signal output. | The '''Tektronix 7A22''' is a single channel differential vertical amplifier for the [[7000-series scopes|7000 series mainframes]], designed by [[Val Garuts]] and produced from about 1969 to 1991. Specifications and controls are similar to the [[26A2]] and the [[3A9]] from the 560 series but without current probe input or front panel signal output. | ||
Remarkably, the 7A22's input sensitivity reaches down to 10 μV/Div. Bandwidth is 1 MHz, the upper 3 dB limit can be reduced in ×3 steps down to 100 Hz (to eliminate noise, inter alia), and the lower bandwidth can be raised in ×10 steps from 0.1 Hz to 10 kHz. A separate control optionally supplies an internal DC voltage to offset the DC signal component. Even in the most sensitive ranges (10 μV/Div to 10 mV/Div), common-mode voltage can be ±10 V. Input resistance is 1 MΩ, but for high source resistance DC coupled measurements, one can disconnect the internal gate return resistors of the input FETs, at the disadvantage of disabling the 20 mV/div and higher ranges. | Remarkably, the 7A22's input sensitivity reaches down to 10 μV/Div. Bandwidth is 1 MHz, the upper 3 dB limit can be reduced in ×3 steps down to 100 Hz (to eliminate noise, inter alia), and the lower bandwidth can be raised in ×10 steps from 0.1 Hz to 10 kHz. A separate control optionally supplies an internal DC voltage to offset the DC signal component. Even in the most sensitive ranges (10 μV/Div to 10 mV/Div), common-mode voltage can be ±10 V. Input resistance is 1 MΩ, but for high source resistance DC coupled measurements, one can disconnect the internal gate return resistors of the input FETs, at the disadvantage of disabling the 20 mV/div and higher ranges. | ||
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==Internals== | ==Internals== | ||
The differential amplifier design is a variant of the [[1A7A]] circuit, also used with modifications | The differential amplifier design is a variant of the [[1A7A]] circuit, also used with modifications in the [[3A9]], [[5A22N]], [[AM502]], and [[5030]]/[[5031]] ([[26A2]] too?). | ||
in the [[3A9]], [[5A22N]], [[AM502]], and [[5030]]/[[5031]] ([[26A2]] too?). | |||
The 7A22 uses the ±50 V supplies provided by the mainframe. | The 7A22 uses the ±50 V supplies provided by the mainframe. | ||