067-1478-00
Power Measurements
Deskew Fixture
Instructions
071-1175-01
Use the table below as a guide to connect a variety
of Tektronix voltage and current probes together
on the deskew fixture.
Connecting to the Instrument
The fixture has two BNC inputs, a large current
loop and a small current loop. Use the BNC cable
(included) to connect the instrument PROBE
COMPENSATION output (TDS7000), AUX
OUT output (TDS5000), or external generator to
either the large or small input. The input you use
depends on the type of probes you have.
CAUTION. The maximum allowable voltage
applied to either input is±7 V RMS. Voltages
in excess of ±7 V RMS may damage the
deskew fixture.
P6139A
Connect the probe tip and the ground lead to the
two terminals as shown.
*P071117501*
071117501
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.
Use this current
loop / input side
Small current loop TCP202
Large current loop TCP303/TCPA300
1
Not all probes are useable with all instruments.
2
Use oscilloscope averaging mode to improve
deskew adjustability.
3
Requires external signal source.
Current
1,2
probes
A6302/AM503XX
A6312/AM503XX
TCP305/TCPA300
TCP312/TCPA300
A6303/AM503XX
Voltage
1,2
probes
Passive:
P6139A
P5050
and other 10X
passive probes
Active
single-ended
and differential:
P6243
P6245
P6246
P6247
P6248
High voltage:
3
P5100
P5200 (500X)
P5205 (500X)
3
P5210
P6135A
P6243 or P6245
Connect the probe tip to the short pin and the
probe ground to the long pin as shown.
3
3
P5200 Series
Connect the probe tip and the ground lead to the
two terminals as shown.
Overview
This fixture converts the PROBE
COMPENSATION output of the TDS7000 or the
AUX OUT output of the TDS5000 into a set of
test point connections that provide you with a
convenient way to compensate for timing
differences between voltage and current probes.
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.
P6246, P6247, or P6248
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.
TCP202, TCP312, TCP305, A6302, A6312, etc.
Connect the current probe around the current loop
as shown. Be sure to align the polarity arrows on
the current probe and the fixture, and make sure
the current probe slider is closed and locked.
TCP303, A6303
Connect the current probe around the current loop
as shown. Be sure to align the polarity arrows on
the current probe and the fixture, and make sure
the current probe slider is closed and locked.
Using the Fixture
Do these steps to use the fixture. For best results,
warm up the equipment for 20 minutes before
performing these functions.
Compensate Probe Timing (Deskew)
1. Connect the small- or large-current loop side
of the fixture to the instrument according to
the operation desired (see the table in
Connecting to the Instrument).
2. Connect the probes to the fixture.
3. Display all channels that you want to deskew.
4. Push the AUTOSET button on the instrument
front-panel.
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 the 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.
Schematic
The schematic diagrams that follow show typical
connections for both small- and large-style current
probes.
Oscilloscope
PROBE COMP out
(TDS7000)
CH1 CH2
AUX out (TDS5000;
back of scope)
Current
BNC cable
probe
Voltage
probe
Deskew
fixture
Figure 1: Typical small current probe connection
Oscilloscope
EXT TRIG
CH1 CH2
Signal generator
TRIG IN
OUT
BNC cable
Current
probe
Voltage probe
Deskew
fixture
Figure 2: Typical large current probe connection using an
external signal source
CAUTION.
The maximum allowable voltage
applied to either input is ±7 V RMS. Voltages
in excess of ±7 V RMS may damage the
deskew fixture.
Copyright © Tektronix, Inc.
Beaverton, OR 97077