Sweep Mode Control - TTI TG420 Manual Del Usuario

Loading Saved Programs
Pressing the LOAD key sets the edit arrow to the LOAD PROG field in the lower line of the
display. Turning the rotary control selects the memory location from which the program is to be
loaded. Having selected the memory number, pressing LOAD twice implements the load routine;
pressing any other key cancels LOAD. The display fills with dots while the load is being
executed.

Sweep Mode Control

With the keys in primary function mode, pressing the EDIT key twice selects the SWEEP
functions shown in the top row of legend above the keys; the lamp beside the SWEEP functions
lights to show that they are selected.
The SWEEP keys control the internal sweep and have the following functions.
Start Frequency
Pressing the START key sets the edit arrow to the START field in the lower line of the display.
The start frequency can then be adjusted with the rotary control. The start frequency can be
either above or below the stop frequency.
Stop Frequency
Pressing the STOP key sets the edit arrow the STOP field in the lower line of the display. The
stop frequency can then be adjusted with the rotary control. The stop frequency can be either
above or below the start frequency.
Sweep Rate
Pressing the RATE key sets the edit arrow to the RATE field in the lower line of the display. The
rate can then be adjusted with the rotary control. The setting resolution is 10ms for rates
between 20ms and 1s; for rates between 1s and 20s the setting resolution is 1s.
Sweep Mode
Pressing the MODE key sets the edit arrow to the SWEEP field in the lower line of the display.
Turning the rotary control steps the sweep mode setting through the choices of OFF, ON LIN
(linear sweep) and ON LOG (logarithmic sweep).
Note that when the sweep mode is on the frequency display on the top line of the display is
suppressed.
External Sweep
External sweep is achieved by applying the sweep signal to the EXT SWEEP input having set the
input to FM, see Configuration Level Control – AM/FM section. The instrument sums the EXT
SWEEP voltage with the internal control voltage derived from the frequency setting to determine
the instantaneous operating frequency. A positive voltage increases the frequency; for frequency
sweeping with positive–going sweep input voltages the internal frequency should therefore be set
to the lower limit of the frequency range to be swept. For example, a 0V to +4V ramp will sweep
the generator approximately 1 decade up from range minimum (set by the FREQUENCY control)
to range maximum.
Similarly, a negative voltage decreases the frequency and for negative–going sweep inputs the
internal frequency should be set to the upper limit of the range to be swept.
To use a signal which is symmetrical about ground, the internal frequency should be set at
approximately the centre of the band to be swept.
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