BNC 630 - Manual (Page 27)

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4. Continuous / Triggered sweep
In this field select whether the sweep is performed continuously or on a single event basis. If you select a Continuous sweep, then
the sweep is immediately restarted once the stop frequency is reached. If you select a Triggered type sweep, then the sweep is halted
once the stop frequency is reached. The sweep is not restarted again until another trigger occurs. The trigger can come from three
sources:
1. Pressing the Trigger key
2. Applying a low-to-high transition on the Ext Trig In connector
3. Sending an ASCII "T" to the RS232 port
The 630 will simultaneously accept a trigger from all of the above sources.
To set Continuous type sweep, press 1 . To set Triggered type sweep, press 0 . Pressing any arrow key or rotating the wheel will
toggle the sweep type between Continuous and Triggered.
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 steps.
In Continuous sweep mode, the sweep may be halted by applying a 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 50 ohm LOADED level. This is the level of the signal which will appear across a 50 ohm 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 waveform. For more information on output offsets refer to section 4.4.
SYNC Out Connector
(front panel)
This TTL/CMOS compatible output supplies a high going pulse at the start of each sweep. Useful for triggering scopes or other
equipment at the start of each sweep.
Ext Gating In Connector
(rear panel connector)
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 a 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 pulldown resistor so that the input is held at a logic low when this input is left unconnected.