8
Operation
Power
The ON/OFF switch is on the rear panel of the instrument.
Frequency Selection
Frequency range is selected by a seven position multiplier switch with fine adjustment by
calibrated vernier. Depressing the SYM button divides the indicated frequency by 10 on TG210;
on TG215/TG230 the digital display correctly shows the resultant output frequency. The
SYMMETRY control varies the duty cycle from 1:9 to 9:1 to produce sawtooth and variable pulse-
width waveforms. Optimum performance of the SYMMETRY control is achieved on the top
decade of each frequency range.
TG215/TG230:
with DISPLAY SELECT set to frequency the auto-ranging meter makes reciprocal
measurements down to 2·30Hz (·230Hz on the 2Hz range); the display update rate in this mode
is 130ms or 1 waveform period, whichever is the longer. Below these frequencies a fast
measurement update rate is maintained by changing the measurement method but accuracy is
reduced, see Specification. If a voltage is applied to SWEEP IN the display correctly shows the
new generator frequency.
When SYM is selected the changeover in frequency measurement happens at ·230Hz on the
20Hz and 2Hz ranges.
Function Selection
The output waveform shape is selected by depressing one of the three function buttons, to give
sine, square or triangle. With all three switches out (accomplished by half-depressing any one)
the output will be a DC level only; this is useful as it permits input threshold testing of a circuit
instead of having to connect up an external DC supply.
Main Output
The amplitude of the 50
Ω
MAIN output is controlled by the 2-position ATTENUATOR switch and
AMPLITUDE control. Maximum output is 20 volts peak-to-peak from 50
Ω
and 10 volts peak-to-
peak when terminated with a 50
Ω
load.
The AMPLITUDE control has greater than 40dB range and used in conjunction with the
ATTENUATOR a range of 0dB to -60dB can be achieved. This provides a range of 20V peak-to-
peak down to 20mV peak-to-peak, or 10V peak-to-peak down to 10mV peak-to-peak into 50
Ω
.
Greater attenuation can be achieved by using standard 50
Ω
BNC attenuators. To maintain
waveform integrity only 50
Ω
cable should be used and the receiving end should be terminated
with a 50
Ω
load. The 50
Ω
MAIN output will withstand a short circuit for a period of 10 minutes at
maximum output and greater periods at lower output levels. However, damage will occur if an
external voltage is connected to the output socket.
TG210/TG215:
The MAIN output is also available from a 600
Ω
socket. The 50
Ω
and 600
Ω
sockets are not independent and should not be used together.
TG215/TG230:
with DISPLAY SELECT set to amplitude, the peak-to-peak amplitude of the MAIN
output is displayed. The display shows open circuit voltage (emf); 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). DC offset plus waveform is attenuated proportionally in the
-20dB position.