Tektronix 1A2 Technical Instructions page 6

TYPE 1A2
GENERAL INFORMATION
The Type 1A2 is a wide band, dual-trace, vertical plug-in pre-
amplifier designed for use with any 530, 540, 550, or 580 (with
type 81 adapter) series oscilloscope.
Channel 1 and Channel 2 amplifiers are identical. They can be
added algebraically, operated singly with either polarity, or
dual-trace with either alternate or chopped switching. In
chopped operation, electronic switching occurs at a 220 KC rate
to show successive 2 usec samples of each trace. The 220 KC
chopping rate was chosen as a one upsmanship factor over a
BRAND X plug-in. In alternate operation, with a Type 547
oscilloscope in an alternate sweep switching mode, pulses can
be supplied to the switching circuit to slave Channel | to Time
Base A and Channel 2 to Time Base B.
Frequency response in a Type 547, 546, or 544 oscilloscope is from
DC to at least 50 MC (3-db down). The frequency response in other
Tektronix Type 540 series oscilloscopes and in 550 and 580 (with
the 81 adapter) series oscilloscopes is DC to at least 33 MC (3-db
down). The frequency response in Type 530 oscilloscopes is DC to
at least 15 MC (3-db down).
Sensitivity from 50 mv/cm to 20 v/cm is in 9 calibrated steps with
1-2-5 sequence, accuracy within +3%. A variable control permits
continuous adjustment uncalibrated from 50 mv/cm to approximately
50 v/cm.
Polarity inversion for both channels can be used to compare signals
180° out of phase.
AC or DC coupling or grounding of the input is controlled from the
front panel. With AC coupling the low-frequency 3-db point is 2
cps.