HP 75000 SERIES C - Page 60

Minimal MARKer
When setting up a sweep with markers in it, or a list sweep with
distances
intervals with markers in it, a minimum distance must be observed
between START
- b MARKER, MARKER - b MARKER and
MARKER
- b STOP. Unfortunately this minimum distance is not a
fixed frequency distance, but
a fixed TIME distance of 1.5 msec.
The minimal frequency distance is determined by the sweep
frequency span
( ABS(ST0P-START) ) and the sweep (dwell) time.
The equation is
:
Example :
:FREQ:START 1 kHz ;
:FREQ:STOP 3 kHz ;
:SWE:TIME 2
min-dist[Hz]
= (2000[Hz] * I.~E-~)
2[sec]
The pitfall here is that one can turn a legal marker into an illegal
marker, by touching nothing except the sweep (dwell) time.
Example
2 : (identical but sweep time is significantly shorter)
I
:FREQ:START 1 kHz ;
:FREQ:STOP 3 kHz ;
:SWE:TIME 0.1
FUNC TTL and FUNC
For the output FUNCtions TTL and DC, some instrument
DC limitations
parameters are fixed. The commands affected for FUNCtion TTL are
VOLT and VOLT:OFFS, the commands affected for FUNCtion DC
are FREQ and VOLT.
If FUNCtion is TTL
:
:VOLT <value> -> error
:VOLT?
-> error, fixed return is 2.4 (typical TTL
level)
:VOLT:OFFS <value>
-> error
:VOLT:OFFS?
-> error, fixed return is 0.0
If FUNCtion is DC :
:FREQ <value> -> error
:FREQ?
-> error, fixed return is 0.0
:VOLT <value> -> error
:VOLT?
-> error, fixed return is 0.0
4-16 Understanding the HP E1440A
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