Tektronix DPO7054, 067-0405-02,above, DPO70804, DPO7104, DPO71254 User manual

067-0405-02 and above

voltage

P6139

A

voltage

P

P6248

CSA/TDS/DPO7000 Series
Probe Calibration and
Deskew Fixture
Instructions

071-0730-05

*P071073005*

071073005

Safety Summary

To avoid potential hazards, use this product only
as specified.

To avoid fire or personal injury

Do not operate in wet/damp conditions.

Keep product surfaces clean and dry.

Safety terms in this manual

WARNING. These statements identify

conditions or practices that could result in
personal injury or loss of life.

Overview

H Compensate for timing differences between

two, three, or four voltage probes (deskew).

H Compensate for timing differences between

one, two, or three voltage probes and a current
probe (deskew).

Connecting to the Instrument

The fixture has two BNC inputs, A and B. Use the
BNC cable (included) to connect the instrument
PROBE COMPENSA TION output to either the A
or B input. The input you use depends on the type
of probes you have and the operation you want to
perform.

2

Probe

Passive
voltage
probes,
including

Active
voltage
probes,
including

P6243

6245
P6246
P6247
P6248
P6249
P7240
P7330

Current
probe

TCP202

Current
probe

CT-6

1

2

Operation Jumper

Low frequency
compensation

Gain and offset
calibration

Compensate timing with
respect to other voltage
probes

Compensate timing with
respect to TCP202
current probe

Compensate timing with
respect to CT-6 current
probe

Gain and offset
calibration

Compensate timing with
respect to other voltage
probes

Compensate timing with
respect to TCP202
current probe

Compensate timing with
respect to CT-6 current
probe

Compensate timing with
respect to voltage
probes

Compensate timing with
respect to voltage
probes

Gain and offset calibration for these probes is
generally not needed.

Not all probes are useable with all instruments.

1

Yes A

No A

Yes A

Yes B

Yes A

No A

Yes A

Yes B

Yes A

Yes B

Yes A

Use
input

Connecting Probes

WARNING. To avoid personal injury, use care

while connecting probe tips to the square
pins on the fixture. The ends of the square
pins are sharp.

The following diagrams show how to attach each
type of probe tip to the fixture. Refer to the
ground symbols screened on the fixture to
establish the correct polarity.

P6139A

Connect the probe tip and the ground lead to the
two terminals as shown.

Aside

connection

Bside

connection

This fixture converts the PROBE
COMPENSATION output into a set of test points
that give you a convenient way to:

H Compensate a passive probe (low-frequency).

H Optimize the instrument gain and offset

accuracy at the probe tip.

NOTE. The A side of the fixture has a small

jumper over two pins. Remove the jumper for
gain and offset calibration. Install the
jumper for all other functions.

P6243 or P6245

Connect the probe tip to the short pin and the
probe ground to the long pin as shown.

P6246, P6247, P6248, or P7330

Connect the probe + input to the signal pin and
the probe -- input to the ground pin as shown.
There is no connection to the probe ground input.

P7330
with
adapter

P6249 or P7240

Connect the probe tip to the short pin and the
probe ground to the long pin as shown.

TCP-202

Snap the current probe closed around the current
loop as shown. Be sure to align the polarity arrows
on the current probe and the fixture.

CT-6

Remove the small jumper on the A side of the
fixture. Slip the CT-6 probe head over the
outboard pin, and then replace the jumper.

After you are finished with this probe, be sure to
replace the small jumper.

Using the Fixture

Do these steps to use the fixture. For best results,
warm up the instrument for 20 minutes before
performing these functions.

Low Frequency Compensation

1. Connect the A side of the fixture to the
instrument.

2. Connect one probe to the fixture.

3. Push the AUTOSET button on instrument.

4. Optimize the adjustment on the probe
compensation box for best square corner.

5. Remove the connections.

Optimize Gain and Offset Accuracy

1. Connect the A side of the fixture to the
instrument.

2. Remove the small jumper from the fixture.

3. Connect one probe to the A side of the fixture.

4. Touch the VERT button or use the Vertical
menu to display the vertical control window.

5. Touch the Probe Cal button to display the
vertical probe cal control window.

6. Select the instrument channel to which the
probe is attached.

7. Touch the Calibrate Probe button.

8. When the routine is finished, remove the
connections and replace the small jumper.

Compensate Probe Timing (Deskew)

1. Connect the A or B side of the fixture to the
instrument according to the operation desired
(see the table in Connecting to the
Instrument).

2. Connect up to four probes to the fixture.

3. Display all channels that you want to deskew.

4. Push the AUTOSET button on instrument.

5. Adjust vertical SCALE,andPOSITION
(with active probes adjusting offset may be
required) for each channel so that the signals
overlap and are centered on screen.

6. Adjust horizontal POSITION so that a
triggered rising edge is at center screen.

7. Adjust horizontal SCALE so that the
differences in the channel delays are clearly
visible.

8. Adjust horizontal POSITION again so that
the first rising edge is exactly at center screen.
The fastest probe is connected to this channel.
(The fastest probe is probably the one with the
shortest cable or the highest bandwidth.)

9. Touch the VERT button or use the Vertical
menu to display the vertical control window.

10. Touch the Probe Deskew button to display the
channel-deskew control window.

11. Select one of the slower channels.

NOTE. If possible, do the next step at a signal

amplitude within the same attenuator range
(vertical scale) as your planned signal
measurements. Any change to the vertical
scale after deskew is complete may introduce
a new attenuation level (you can generally
hear attenuator settings change) and
therefore a slightly different signal path. This
different path may cause a 200 ps variation
in timing accuracy between channels.

12. Adjust the deskew time for that channel so
that its signal aligns with that of the fastest
channel.

13. Repeat steps 11 and 12 for each additional
channel that you want to deskew.

14. Remove the connections.

Copyright © Tektronix, Inc.

Beaverton, OR 97077