Stanford Research Systems DS345, Руководство пользователя

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Function Setting
2-12
TTL levels are 5 V
pp
with a 2.5V offset (the output will swing between 0 and
+5V).
ECL Settings
Pressing [SHIFT][ECL] sets the output amplitude and offset to ECL values.
ECL levels are 1 V
pp
with a -1.3V offset (the output will swing between -1.8V
and -0.8V).
DC OFFSET
The DC offset may range between ±5V, but is restricted such that |V
ac peak
|
+ |V
dc
| ² 5 V. When [OFFST] is pressed a new value may be entered using
any amplitude unit key, the V
pp
indicator LED will be lit . When the offset is
changed the output signal will briefly go to zero as the output attenuators are
switched. If the amplitude is zero, the offset may be set with three digits of
resolution. If the amplitude is not zero the larger of the amplitude and offset
determines the resolution of both parameters. The offset display is automati-
cally adjusted such that all of the digits that may be changed are displayed.
PHASE
Press [PHASE] to display and modify the phase of the FUNCTION output.
Phase is always measured with respect to the internal timebase,
not
the
SYNC output. The phase may be changed with the keypad and the DEG unit
key, or using the MODIFY keys. The range of the phase setting is
±7199.999° and may be set with 0.001° resolution. If the function is set to
NOISE, ARB, or modulation is enabled in SWEEP, FM, or PM modes the
phase cannot be changed and the message "no Phase" will be displayed. In
BURST modulation mode the PHASE function will set the waveform phase
at the start of the burst. This is quite useful for starting the burst at a particu-
lar point in the waveform.
Zero Phase
The current phase may be assigned the value zero by pressing [SHIFT]
[REL=0]. Subsequent changes to phase will be relative to this value.