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HP4402.book : chapter2.fm 14 Fri Feb 12 15:32:45 1999
Power Meter Operation
Zeroing and Calibrating the Power Meter
2-14 HP E4419B User’s Guide
Effective control of the zero and calibration cycles using the TTL inputs
depends on correct timing of the input signals as shown in Table 2-3 and
Table 2-4.
Table 2-3: TTL Input Timing Diagram 1
Timing of zero/cal inputs for conditions “01” and “10”.
Time Description Value
T1 Minimum width of input 300 ms
T2 Time between input detection and start of zero/cal
cycle. This is determined by the number of
averages x sample rate, or if there is an existing
zero/cal operation in progress, the time for this
current operation to complete. Note that the
worst case is 1024 averages x 50 ms = 51.2 s. For
front panel operation (in free run mode) the time
is 1 x 50 ms.
Max: 50 ms (typical)
Min: 0 ms
T3 Maximum width of input. Longer inputs may
cause a subsequent zero/cal operation some time
after the current one is complete.
4 s
T4 Time for zero/cal operation to complete. Zero Both: 10 s (each
8480 series sensor), 12 s
(each E series sensor)
Cal: 6 s (8480 series)
7 s (E series)
All timings based on 100 ms firmware polling.
T1
T2
T3
T4
Input
Operation