Offset; Width, Delay And Period Relationships - Tektronix PFG 5505 Instruction Manual

Operating Instructions

Offset

The offset parameter can add a positive or negative
de level to the output waveform. Refer to the Electrical
Specifications for combined output/offset level limita­
tions.
To use OFFSET, press the OFFSET key, enter the
offset voltage level, select units if appropriate, press
ENTER. The OFFSET key LED is on while the offset
level is not 0. To t urn the offset off, repeat the process
described above, setting the offset level to O (LED
off). If an illegal offset combination is entered, an
error will be generated.

Width, Delay and Period Relationships

The PF G 5105/5505 has automatic lockout of illegal
width, delay and period combinations in Pulse Mode.
Settings that do not meet the criteria will cause an
error message to be returned. See Fig. 2-8 for the
correct relationship between width, delay and period.
Delay
Single
Pulse
Double
Pulse
Sync
Pulse
�
Ti m
Minimum �ecovery
See Table 2·5
Fig. 2-8, Relationship Between Width, Delay and Period.
2-1 6
0.1 • Period
�
and >40 ns
Width
I
l
Single Pulse Mode
Two equations describe the allowable combinations
of width, delay and period.
Equation One:
delay + width speriod * 0.85
Equation Two:
period - (delay + width) > 40 ns
Using these equations, the following settings can be
shown to be legal :
delay = O
width = 359 ns
period = 400 ns (1 /2.5
Substituting these settings into Equation One
O + 359- 9 s 400 ns
*
359- 9 s 360- 9
The equation is true, so the settings are legal.
The equation is also true when the settings are
substituted into Equation Two:
400- 9 - (359- 9 + O) � 40- 9
41- 9 � 40- 9
Settings may be illegal even if only one equation is
false. For instance, the following settings are illegal
because they will return a period - (width + delay)
= 40 ns (Equation Two):
o
delay =
width = 360 ns
period = 400 ns (1 /2.5
And, because they give a false return on Equation
One, the following settings are illegal :
o
delay =
width = 451 ns
period = 500 ns (1/2.00
PF G 5105/5505 Instruction Manual
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0.85
)
6
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