Tektronix 2215A, Instruction Manual

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Operating Instructions— 221
5A
Service
should not be required. If adjustment is needed, perform the
following procedure:
1. Preset instrument controls and obtain a baseline trace.
2. Use the Channel 1 POSITION control to move the
baseline trace to the center horizontal graticule line.
3. If the resulting trace is not parallel to the center hori­
zontal graticule line, use small flat-bit screwdriver to adjust
the TRACE ROTATION control and align the trace with the
center horizontal graticule line.
PROBE COMPENSATION
Misadjustment of probe compensation is a common
source of measurement error. Most attenuator probes are
equipped with a compensation adjustment. To ensure opti­
mum measurement accuracy, always compensate the oscil­
loscope probes before making measurements. Probe
compensation is accomplished as follows:
1. Preset instrument controls and obtain a baseline trace.
2. Connect the two 10X probes (supplied with the instru­
ment) to the CH 1 and CH 2 input connectors.
3. Set both VOLTS/DIV switches to 10 mV and set both
Input Coupling switches to DC.
4. Select CH 1 VERTICAL MODE and insert the tip of the
Channel 1 probe into the PROBE ADJUST output jack.
5. Using the approximately 1-kHz PROBE ADJUST
square-wave signal as the input, obtain a 5-division display
of the signal.
6. Set the A SEC/DIV switch to display several cycles of
the PROBE ADJUST signal. Use the Channel 1 POSITION
control to vertically center the display.
7. Check the waveform presentation for overshoot and
rolloff (see Figure 2-9). If necessary, adjust the probe com­
pensation for flat tops on the waveforms. Refer to the in­
structions supplied with the probe for details of
compensation adjustment.
8. Select CH 2 VERTICAL MODE and connect the Chan­
nel 2 probe tip to the PROBE ADJUST output jack.
9. Use the Channel 2 POSITION to vertically center the
display and repeat step 7 for the Channel 2 probe.
10. Disconnect the probes from the instrument.
KX
9<
CORRECT
(FLAT)
OVER C O M ­
PENSATED
(OVERSHOOT)
1C
UNDER C O M ­
PENSATED
(ROLLOFF)
....
r ~
C4732-15
Figure 2-9. Probe compensation.
2-10