9
The amplitude is displayed on the right-hand side of the LCD (not TG310); pressing the
PK-PK/RMS button beside the display will alternate the reading between peak-to-peak volts
(Vp-p) and r.m.s. volts (Vrms). The readout is correctly adjusted for attenuator setting and
waveform shape. The display shows open circuit voltage; the actual voltage at the socket will be
half the displayed value when the output is terminated with its characteristic impedance.
DC Offset
The DC OFFSET control has a range of ±10 volts from 50
Ω
/600
Ω
in all output modes; the control
has a centre detent for 0 volts. DC offset plus signal peak is limited to ±10V (±5V into the
characteristic output impedance); CLIP shows in the display when this limit is exceeded.
DC offset plus waveform is attenuated proportionally by the ATTENUATOR switches.
The DC offset can be displayed in place of the output amplitude by pressing the OFFSET button
beside the display (not TG310). The display shows open circuit voltage offset; the actual voltage
at the socket will be half the displayed value when the output is terminated with its characteristic
impedance.
Auxiliary Output
The AUX OUT output provides a fixed 0 to 5V TTL/CMOS pulse output at the same frequency,
symmetry and phase as the MAIN OUT outputs and is capable of driving 2 standard TTL loads.
Internal Sweep
(TG330 only)
With INT SWEEP selected the output of the internal sweep generator is summed with the
FREQUENCY vernier. Select LIN or LOG sweep mode; the annunciators LIN-SWP or SWP-LOG
will show in the display accordingly.
Frequency Selection
Using the FREQUENCY RANGE switches select the lowest range within which the upper sweep
limit can be set; in this way the best setting resolution and the widest sweep range can be
realised.
Sweep Limits
Turn the STOP control to minimum (fully-anticlockwise). Hold the SET START button and set the
START (lowest) frequency on the display using the FREQUENCY vernier; the START frequency
must be set first. Now release the SET START button, hold in the SET STOP button and set the
STOP (highest) frequency on the display using the STOP control; release the SET STOP button.
Note that both the FREQUENCY vernier and the STOP control have a log characteristic when
LOG mode is selected.
The sweep limits can be checked at any time by depressing the SET START or SET STOP.
Sweep Rate
The generator sweeps both up and down at the speed set by the RATE control, i.e. it does not
reset rapidly after the upward sweep. This has the advantage that the suitability of the selected
sweep time can be continuously monitored.
Sweep Out
When INT SWEEP is selected the SWEEP IN/OUT socket becomes an output providing a 0V to
3V ramp from 600
Ω
impedance to drive the X-input of an oscilloscope or chart recorder.
Terminating this output with a resistor will reduce the output amplitude. Terminating with 600
Ω
will
halve the output giving 0V to 3V.
Holding in the SET STOP button holds the ramp at the maximum and can therefore be used to
set full scale on the oscilloscope or chart recorder.
Note that when SWEEP IN/OUT is used as an output to drive the X-input of an oscilloscope, the
oscilloscope should be set to DC coupling and not AC coupling which will cause a double image
at slow sweep speeds.