B&K 4070A - Manual (Page 26)

BK Precision 4070A User Manual Rev.2.2
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5. Up / Down sweep
In this field select the direction of the sweep. An up sweep begins at the start frequency and ends at the end
frequency. A down sweep begins at the end frequency and ends at the start frequency.
To set Up type sweep, press 0. To set down type sweep, press 1. Pressing any arrow key or rotating the wheel will
toggle the sweep between Up and Down.
6. Sweep time
In this field you specify how long it takes the sweep to increase the frequency from the start frequency to the stop
frequency. You may enter 1 mS to 60,000 mS (60 seconds) in 1 mS step. In Continuous sweep mode, the sweep may
be halted by applying logic high to the Ext Gating Input connector on the rear of the unit. Doing so also halts the
sweep timer, i.e. the sweep time will be lengthened by the amount of time that the sweep is halted.
7. Level
In this field enter the output level, from 4 mVp -p to 10 Vp -p in 1 mV steps or from -44.0 dBm to +24.0 dBm in .1
dBm steps.
NOTE: The level specified is a 50O loaded level. This is the level of the signal, which will appear across a 50O
load connected to the SIG Out connector. Into an open circuit, the output swing will be twice the value entered.
Offset
You can enter an offset voltage for the output signal. For more information on output offsets refer to section 4.4.
SYNC Out Connector
This TTL/CMOS compatible output supplies a high going pulse at the start of each sweep. That could be useful for
triggering scopes or other equipment at the start of each sweep.
Ext Gating Input
This TTL compatible input is used in two different ways, depending on whether the sweep mode is Continuous or
Triggered. In Continuous sweep, the user can halt the sweep "dead in its tracks" by applying logic high (+3V to
+10V) on this jack. The output frequency will be held constant until the input is brought low again. The sweep will
then resume toward the stop frequency. In Triggered type sweep, this input functions as an external sweep trigger
input. A logic low-to-high transition on this input will trigger the sweep. This input has an internal pull down
resistor so that the input is held at a logic low when this input is left unconnected.