General Information - Tektronix 2A61 Instruction Manual

General Information
The Type 2A61 is a high sensitivity differential amplifier
designed for use with all Tektronix 560-series Oscilloscopes.
The amplifier provides calibrated deflection factors from
10 pV/division to 20 mV/division in a 1-2-5 sequence.
The upper and lower cutoff frequencies of the amplifier
are adjustable. In addition, a line frequency notch filter can
be switched in to minimize signals in the power line fre-
quency region.
SECTION I!
Type 2A61
CHARACTERISTICS
A trace restorer pushbutton returns the trace if it is driven
off the CRT graticule area by a large transient.
A front panel control, the Input Selector, can connect the
amplifier input to an internal common mode signal for a
check of common mode rejection; ground the inputs of the
amplifier for a no-signal reference display; select either
Input A or B; or select A minus B.
The following characteristics apply over an ambient tem-
perature range of 0° C to 50° C. Warm-up time to reach
specified performance is 20 minutes at 25° C, 5° C.
Characteristic
Performance Requirement
Supplemental Information
Deflection Factor
0.01 mV/div to 20 mV/div, =5%
GAIN AD§J control properly set and VARI-
ABLE at CALIB. Steps in 1-2-5 sequence.
VARIABLE range >2.5 to 1
Maximum Bandwidth
<0,06 Hz to >0.3MHz, at 20 mV/div
<0.1 Hz to >0.1 MHz, at 0.01 mV/div
FREQ RESPONSE TO
switch (High Frequency —3dB
point)
Selectable in fixed steps. Within 30%
of indicated frequency at 300-100 kHz (de-
pending upon mV/div switch setting}, 60
kHz, 6kHz, 600 Hz and 60 Hz.
Risetime (10-90%}. (Based on cutoff fre-
quency within +30% of front-panel fre-
quency indication.)
60 kHz 4.5 to 8.3 ps
6 kHz 45 to 83 ys
600 Hz 0.45 to 0.83 ms
60 Hz 45 to 8.3 ms
FROM switch (Low Frequency —3
dB point)
Selectable in fixed steps. Within +30%
of indicated frequency at 0.06 to 0.1 Hz (de-
pending upon mV/div switch setting}, 0.6
Hz, 6Hz, 60Hz and 600 Hz.
Decay Time Constant (Based on cutoff fre-
quency within +30% of front-panel fre-
quency indication).
600 Hz 0.21 to 0.37 ms
60 Hz 2.1 to 3.7 ms
6 Hz 21.0 to 37.0 ms
0.6 Hz 0.21 to 0.37 s
POSITION control Range > +6 divisions
Short Circuit Noise
<3.5 uV (RMS), referred to input, (0.01 mV/
div and maximum frequency response).
2220 uN peak to peak. Input at GND.
Grid Current
A, —B input grid current, 10nA (nano-
amperes) max.
Input R and C
10 Megohms, +1%, paralleled by approxi-
mately 100 pF
For each input to ground
Line Filter
Attenuation at 60 Hz
>50:1 (with 60Hz filter}
Insertion Loss
<15% at and above 1 kHz (with 60 Hz
filter)
Filters for 50Hz and 400Hz available
(60 Hz standard)
Common Mode Rejection Ratio
50,000:1 below 10 kHz, 5V peak to peak
common mode sine-wave input.
MILLIVOLTS/DIV switch set to .05
Maximum Common-Mode
Voltage
Input
+5V A—B mode
1-1