5-22 Delta, Pulse Delta, and Differential Conductance Model 6220/6221 User’s Manual
Return to Section 5 topics
Where: Y is the measurement at the high pulse.
X is the measurement at the first low pulse.
Measurement units
The fundamental Pulse Delta measurement explained above is in volts. The read-
ing can instead be converted into Ohms (W), Siemens (S), or Power (W). Details
on selecting “Measurement units” are provided on page 5-11.
Peak power and Average power
With Power units selected, a Pulse Delta reading can be expressed (and dis-
played) as a Peak power reading or an Average power reading. Peak power is the
default setting. See “Measurement units” in Section 5 of the Reference Manual for
details on Peak power and Average power for Pulse Delta.
Pulse Delta outputs
Pulse Delta output is made up of one or more Pulse Delta cycles. Each cycle is
made up of three output pulses (low, high, and low). The time period for a cycle is
adjustable and is the same for all cycles. The output pulses have an adjustable
pulse width, which is the same for all pulses.
There are two basic Pulse Delta output types: Fixed output and Sweep output. For
Fixed output, all high and low pulses are fixed for all Pulse Delta cycles in the test.
For Sweep output, the sweep (SWP) function of the Model 6221 is used to output
a staircased, logarithmic, or user-specified (custom) pulse sweep.
Fixed output
Figure 5-8 shows one Pulse Delta cycle for a Fixed output. As shown, the
Model 6221 outputs a low pulse, a high pulse, and then another low pulse during
every Pulse Delta cycle. The pulse width is adjustable and is the same for all high
and low pulses. The cycle interval is also adjustable and is based on the set num-
ber of power line cycles. The Pulse Delta interval shown in Figure 5-8 is set for 5
PLC (power line cycles), which is the default setting. After the set interval expires,
the next Pulse Delta cycle starts (if pulse count is >1).
Pulses are synchronized to the frequency of the power line voltage. When Pulse
Delta is started, the three pulses (low, high, and low) are generated on the
positive-going edges of the first three power line cycles. For the remaining power
line cycles in the interval, the output remains at the I-Low level.
Sweep output
The sweep feature of the Model 6221 can be used to output a series of pulses
that allow the use of different levels for the high pulses. Each high pulse returns to
the programmed low pulse level. The low level is the same for all pulses.
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