Characterization Tools & Solutions
THIS POINT MAY BE
SUBJECT TO A TRIGGER
LEVEL SETTING
TRIGGER
DELAY
PULSE-DELAY
WIDTH
INTERCHANNEL
DELAY/SKEW
DELAY A
CHANNEL B
OUTPUT
CHANNEL A
OUTPUT
DOUBLE-PULSE
OUTPUT
OUTPUT
TRIGGER
OUTPUT
INPUT
SIGNAL
DOUBLE PULSE
DELAY B
SPECIFIED
WIDTH
EQUIVALENT
WIDTH
SLOWEST
TRANSITION
FASTEST
TRANSITION
MEDIAN
SHIFT
DISPLAYED
DELAY
START-POINT
SHIFT (ROLL-OFF)
PERIOD
WIDTH
100W/P
ACCURACY WINDOW
REPEATABILITY BAND
442
10
Pulse and Pulse/Pattern Generators
Accessories
1. With BNC connectors
HP 15104A Pulse Adder/Splitter: 50 ohm delta network,
rise time 150 ps, 6 dB insertion loss, 2 W
HP 15116A Pulse Inverter: 50 ohm pulse transformer,
5% droop (500 ns pulse), 0.3 dB insertion loss, 0.75 W
HP 15115A Splitter-Inverter: 50 ohm delta network with
pulse transformer in one output. Output skew: 1 ns,
other specs as HP 15104A/15116A.
2. With SMA connectors
HP 11667B Pulse Adder/Splitter: 50 ohm series network,
26.5 GHz bandwidth, 6 dB insertion loss, 0.5 Ω
Pulse Parameter Definitions of Terms Used in Instrument Specifications
Time Reference Point: Median (50% amplitude point on
pulse edge).
Pulse Period: The time interval between the leading edge
medians of consecutive trigger output pulses.
Trigger Delay: Interval between trigger point of input
signal and the trigger output pulse’s leading-edge median.
Applies in trigger, external width, gate and burst modes.
Pulse Delay: Interval between leading-edge medians of
trigger-output pulse and output pulse.
Double-Pulse: Interval between leading-edge medians of
the double-pulse.
Interchannel Delay/Skew: Interval between corresponding
leading-edge medians.
Pulsewidth: Interval between leading and trailing-edge
medians.
Additional Information for Pulse Generators with
Variable Transition Times
Pulsewidth: The specified
and displayed value are those
which are obtained with the
fastest edges, essentially
equal to the interval from the
start of the leading edge to
the start of the trailing edge.
By designing the pulse
edges so that they turn about
their start points, the interval
from leading-edge start to
the trailing-edge start stays
unchanged* when transition
times are varied. This is more
convenient for programming,
and the width display is easy
to interpret.
* In practice, start points may shift
with changes in transition time.
Delay: The specified and displayed values are those
obtained with the fastest leading edge. For a slower edge,
the actual delay exceeds the displayed delay by the
combined shift of the start point and the median.
Applications
Typical application areas are:
• clock distribution
• disk drive testing
• general-purpose logic testing
• laser/optoelectronic testing
• LCD-display testing
• memory/flash memor y testing
Transition Time: Interval between the 10% and 90%
amplitude points on the leading/trailing edge.
Linearity: Peak deviation
of an edge from a straight
line through the 10% and
90% amplitude points,
expressed as a percentage
of pulse amplitude.
Jitter: Short-term instability of one edge relative to a
reference edge. Usually specified as an rms value, which
is one standard deviation or ”sigma”. If the distribution is
assumed to be Gaussian, six sigma represents 99.74% of
the peak-to-peak jitter.
The reference edge for the period jitter is the previous
leading edge, whereas the reference edge for the delay
jitter is the leading edge of the trigger output. Width jitter
is the stability of the trailing edge with regard to the
leading edge.
Stability: Long-term average instability over a specific time,
for example, an hour, or a year. The jitter is excluded.
Pulse Amplitude: Pulse output is specified as pulse top
and pulse base (usually referred to as high level and low
level), or as peak-to-peak
amplitude and median offset.
A “window” specification
shows the limits within which
the pulse can be positioned.
Preshoot, Overshoot, Ringing:
Preshoot and overshoot are
peak distortions preceding/
following an edge. Ringing
is the positive-peak and
negative-peak distortion,
excluding overshoot, on
pulse top or base. A combined preshoot overshoot,
ringing specification of e.g.
±5% implies:
• Overshoot/undershoot <5%
• Largest pulse top
oscillation < ±5%
of pulse amplitude
Transition Time Converters:
These components are for use when a very smooth pulse is needed,
or when the stimulus is too fast for the DUT (as evidenced by excessive
cross-talk, ringing, etc). The converters use a patented absorption
technique for minimum reflection and to allow cascading.
Model Output Transition
HP 15435A 150 ps
HP 15432B 250 ps
HP 15433B 500 ps
HP 15434B 1 ns
HP 15438A 2 ns
Settling Time: Time taken for pulse levels to settle within
a level specification, measured from a 90% point on the
leading edge.
Duty Cycle: Percentage ratio of pulsewidth to period. In
pulse/function generators, this term is also used to define
sine and triangle symmetry. Note that in pulse generators,
this is a secondary parameter derived from the period and
width settings. The duty cycle achieved is therefore subject
to width and period accuracies.
Output Impedance/Resistance: Effective pulse source
impedance/dc resistance.
Reflection Coefficient: Reflection at the pulse generator
output expressed as a percentage of the incident pulse
amplitude. (Test pulse edges correspond to the generator’s
fastest transitions.)
Repeatability: When an instrument operates under the same
environmental conditions and
with the same settings, the value
of a parameter will lie within a
band inside the accuracy window.
Repeatability defines the width
of this band.
HP-IB Programming Times
Listen Time: The time an instrument occupies the bus to
receive and verify a message. The NRFD signal is active
during this period.
Settling Time: The time taken by the instrument to execute an HP-IB message and for the output to settle within
the accuracy specification. NRFD inactive.
Execution Time: The sum of Listen Time and Settling Time.
Talk Time: The time an instrument occupies the bus to
output a specified string. Output data is typically instrument error status, or current or stored parameters.
For more information, visit our web site:
http://www.hp.com/go/dvt
• Mixed signal/A/D-, D/A converter testing
• Physical research
• Radar/microwave testing
• Transmission test
• Trigger Source for system test
If you would like to learn more about these applications or customer case
studies, please refer to the application section under www.hp.com/go/dvt.
42.23
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